Domain I: Principles of Dietetics Flashcards
Nutritive value of Fruits and Vegetables
- 75-93% water, carbohydrates (digestible and indigestible)
- Some minerals (calcium in oranges, greens), vitamins C, A, some B
Structure of Fruits and Vegetables
crispness (state of turgor) is due to the osmotic pressure of water-filled vacuoles
Fruits- chemical changes due to enzymes during ripening
Starch changed to sugar;
protopectin converted to pectin (ripe fruit) then converted to pectic acid (overripe fruit)
What gas accelerates ripening of fruit during storage?
Ethylene
At what temperature should frozen fruit be stored?
At or near 0F
At what temperature should dried fruit be stored?
Room temperature
Which fresh fruits are best stored at room temperature?
Avocados, bananas, pears, and tomatoes
What is the method for delaying apples aging through a controlled atmosphere?
Reduced oxygen
Climacteric fruits
Ripen post-harvest (peach, pear, banana, apple, tomato)
Non-climacteric fruits
Best when ripened before harvest (grapes, melon, citrus)
Chlorophyll
- green
- insoluble in water
What happens to chlorophyll in acid?
Turns olive green; pheophytin
What happens to chlorophyll in alkaline?
Turns bright green and mushy; chlorophyllin; hemicellulose broken down
Carotenoids
- yellow, orange
- insoluble in water
- little effect in acid or alkaline solution
Lycopenes
- type of carotenoid
- antioxidant
- phytochemical
Anthocyanins
- flavonoids
- red, blue, purple
- soluble in water
What happens to anthocyanins in acid?
turn bright red
What happens to anthocyanins in alkaline?
turn bluish
Anthoxanthins
- flavonoids
- colorless, white to yellow
- soluble in water
What happens to anthoxanthins in acid?
bleaching effect
What happens to anthoxanthins in alkalines?
turn yellow
What happens to anthoxanthins when cooked in an aluminum pan?
Turn yellow, flavones chelate aluminum
Preparation and processing of fruits and vegetables (raw)
- wash to remove dust and spray residues
- berries and mushrooms should be washed just before serving
How do you prevent the rapid darkening of fruits low in vitamin C when cut due to enzymatic action?
- dip in citrus juice,
- add sugar before freezing,
- heat to boiling
How much juice will one dozen oranges yield?
One quart
Preparation and processing of fruits and vegetables (cooked)
- softens cellulose
- increases keeping quality
- cooks starch
When sweetener is added to liquid of packing juice, what is the density of the syrup expressed as?
- % weight of sucrose
- measured in degrees Brix by a Brix hydrometer
- On label as extra light, light, heavy, extra heavy syrup
What is coulis?
Thin puree of fruit and vegetables, sugar, and water; used as a sauce
What is a compote?
fruit cooked (stewed) in syrup
Potatoes have phenolic compounds which cause color changes in raw, peeled, or bruised potatoes
- Green color under skin- due to chlorophyll that develops when potato is exposed to light during storage. May be accompanied by solanine, a natural toxicant
- Starch changes to sugar during storage (changes in taste, color, and texture) Old potatoes taste sweeter, cook to darker brown (Maillard reaction), and are softer in texture
Fruits and Vegetables
Cooking methods-boil
- small amount of a salted water for a short time, covered pan unless otherwise indicated
- Acidic vegetables that need more time to cook: use more water, no lid
Fruits and Vegetables
Cooking methods-steam
perforated container, covered, over boiling water
Fruits and Vegetables
Cooking methods-pressure cooking
retains color, flavor; cut small
Fruits and Vegetables
Cooking methods-stir-fry
use tender vegetables, high in moisture; don’t drain
Fruits and Vegetables
Cooking methods-frozen
shorter cooking time than fresh because blanching and freezing have made them tender
Fruits and Vegetables
Cooking methods-blanching
immersion in boiling water for a short time
Cauliflower preparation suggestions
cook for a short time, covered
Broccoli preparation suggestions in microwave
less time, same flavor, slightly better retention of color, better retention of vitamin C, no large difference in eating quality
Cabbage preparation suggestions
minimize the development of a strong flavor: cook for a short time, keep lid off initially to let acids escape, cook in large amount of water
Can sizes: #10
6/case
6 lbs 9 oz
13 cups
20-25 servingss
Can sizes: #3
12/case
46 ounces
5 3/4 cups
12-15 servings
Can sizes: #2 1/2
24/case
1 lb 13 oz
3 1/2 cups
6-8 servings
Can sizes: #2
24/case
1 lb 4 oz
2 1/2 cups
4-6 servings
Can sizes: 300
24/case
14-16 oz
1 3/4 cups
3-4 servings
Flavor of vegetables
- sugars in peas and corn
- glutamic acid found in young vegetables- used in form of salt (MSG)
- sulfur- onion, cabbage; when cut, enzymes and sulfur are mixed; cook Brussel sprouts uncovered with little water for best flavor
Flavor of fruits
- Due to acids, sugars, aromatic compounds
- tannins cause astringent feeling in mouth (unripe banana)
Grades USDA fruits and vegetables- based on
- quality
- firmness
- color
- maturity
- freedom from defects
- uniform size and shape
Grades USDA- canned fruits and vegetables
Grade A- desserts, salads (Fancy)
Grade B- processed (Choice)
Grade C- pudding, pie (Standard)
Grades USDA- fresh produce
Fancy, Extra #1, #1, Combination, #2
Myofibrils
bundles of fibers muscle is composed of
Sheet of connective tissue holding muscle fibers in bundles
- collagen
- elastin
Collagen
structural part of tendon that surrounds muscle; in heat- hydrolyzed to gelatin, becomes tender
Elastin
resistant to heat, little change in cooking
Sheet of connective tissue holding muscle fibers in bundles
- collagen
- elastin
Meat, poultry, fish-fat structure
deposited around organs, muscles, in muscles (marbling); finish-amount of fat cover on carcass
Meat, poultry, fish-shape of bone
identifies cut: round bone-leg, T-bone- back and ribs
Nutritive value of meat, poultry, fish, meat alternative
- 16-23% protein
- carbohydrate- glycogen in liver, glucose in blood
- vitamins, minerals- thiamin, niacin, riboflavin, iron, copper, trace minerals (pork is a good source of thiamin)
- calcium content is high in fish canned with bones, oysters, shrimp
Pigments in meat
Myoglobin + oxygen -> red -> brown -> green
(green colors are due to further myoglobin breakdown)
Post-mortem changes and aging
- hold in cold storage to age and ripen- about 10 days
- aging increases tenderness
- change in muscle protein brought about by enzymes which increase the water-holding capacity of the muscle
- acid (vinegar) and salt also increase tenderness by increasing water-holding capacity of muscle
- physical activity of animal will NOT increase tenderness
Anaerobic (Sous vide)- meat storage
vacuum-packing meat in an oxygen-impermeable film, stored unfrozen at 0C; extends storage life of meat
MAP (modified atmosphere packaging) -meat storage
prolongs shelf life; air (oxygen) is removed and replaced with gasses (carbon dioxide, nitrogen); prevents deterioration by slowing respiration
Meat inspection- USDA
mandatory; done at slaughter
shown with round purple stamp “USDA Inspected and Passed”
Wholesome Meat Act of 1967
assures consumer that the animal was healthy at the time of slaughter and the meat is fit for human consumption (assures wholesomeness)
Meat grading- USDA
- indicates quality
- appears on shield
- states federally graded by Agricultural Marketing Service of the USDA
- Grades: prime, choice, select, standard (determined at slaughter)
- Based on maturity of animal, marbling of fat, color and texture of lean
- standard grades have the least marbling; prime the most
Meat specifications
- Uses a numbering system for order wholesale cuts
- IMPS-Institutional Meat Purchasing Specifications
- NAMP- National Association of Meat Purveyors
Cooking principles (meat)
- 325F for roasting
- high temperatures increase shrinkage, toughen
- a slow-cooked roast yields less waste
- insert meat thermometer BEFORE cooking
Safe minimum internal temperatures
145F pork, beef, veal, steaks, roast, fish
160F ground beef, ground veal, ground lamb
165F turkey, chicken, duck
Physical and chemical changes- meat protein
coagulates
Physical and chemical changes- meat collagen
hydrolyzed to gelatin and softens; tough cuts need to be cooked well done because they have more collagen which needs more time to soften
Physical and chemical changes- meat surface browning
due to breakdown of pigments
Physical and chemical changes- meat interior color during cooking
heat changes interior from red to pink to brown to gray; heat denatures globin; iron is oxidized
Physical and chemical changes- meat dehydration
heat to 160F before dehydrating (beef jerky)
Physical and chemical changes- cured meat
pink from nitrites (inhibit botulism)
Tempering meat
allows to cook more evenly
Methods of cooking- dry heat
no water involved, for tender cuts near backbone (loin, sirloin)
frying, broiling, roasting, grilling
Methods of cooking- frying
desirable for fat used to have high smoke point >400F
Do not fry tough cuts of meat (bottom round)
Smoke point
temperature to which fat can be heated before puffs of smoke occur
Smoke point-decreasing order
Safflower (513), soybean, canola, corn, palm, peanut, sunflower, sesame, olive (375), lard (375), shortening (365-370), butter (350)
Monoglycerides (shortening) have lower smoke points
Rancidity
the uptake of oxygen in an unsaturated fatty acid
healthiest plant oils are all highly unsaturated (olive oil has more MUS; less susceptible to rancidity than soybean oil which has more PUS)
Methods of cooking- broiling
form of radiated heat
Methods of cooking- roasting
when meat is removed from oven, “carry-over-cooking” occurs for about 10 minutes; internal meat temperature will rise 15-25F
allow roast to stand 30 minutes before carving
Methods of cooking- grilling
form of dry heat cooking
Methods of cooking- moist heat
water involved, less tender cuts with more connective tissue (bottom round, chuck roast)
braising, simmer, steam, stewing
Methods of cooking- braising
flour meat, brown, cover, and simmer in liquid; in oven or range-top
Methods of cooking- simmer
heat in water to 170-185F with appearance of bubbles
Methods of cooking- steam
heat over, not in, water
Methods of cooking- stewing
add water or other liquid during cooking
Proteolytic enzyme (papain)
tenderizes meat (blend of papaya and salt)
Meat alternative: soybeans
- methionine is the limiting amino acid
- protein concentrates: >70% protein; protein isolates >90% protein
- used in textured protein products (TVP); mixed with ground meats-extends the number of servings, lowering costs; soy protein adds juiciness because of water content
- edamame (soybean pod), tofu (coagulated soy protein), miso (paste of soy and grains), tempeh (aged soybean and grain), natto (fermented soybeans)
Fish cookery
- use dry or moist heat
- more perishable than meat so store at lower temperatures
- fresh fish should have bright red gills and bright, shiny skin
Surimi
purified and frozen minced fish with a preservative, used in analogs, may have egg white or starch added to create desired structure
histamine toxicity
linked to inadequate refrigeration of tuna, mackerel, mahimahi
Eggs-structure
- porous shell- exchanges moisture and gasses; covered with bloom that prevents excessive loss and protects contents
- color of shell is unrelated to food value or quality
- inner membrane contracts leaving air space in large end
- air space becomes larger with age
- high proportion of thick white is indicator of good quality
- yolk is surrounded by vitelline membrane, chalazae are yolk anchors
Egg-nutritive value
- 80 calories, 6 grams protein, 5 grams, fat, vitamins A, D, riboflavin
- yolk is more concentrated than white (more protein, fat, minerals, and vitamins by weight)
- fat is present in an emulsified form (egg yolk=naturally occurring oil in water emulsion)
- color of yolk depends on amount and type of pigment in hen’s diet
Egg-grades
AA, A, B
thickness of white, location and condition of yolk
viewed by candling (pass an egg in front of bright light to view contents)
Egg-grades do NOT include
color of shell, nor size of egg
Egg size
based on weight per dozen
Egg freshness
raw eggs can be stored in refrigerator at 40-45F for 3-5 weeks
Grade A eggs can be maintained for 6 months in cold storage
A fresh egg will sink to bottom in pan of cold water and has dull, rough shell
Egg coagulation
- protein coagulates at 62-70C (sets a custard)
- used to bind, gives firmness, stability, coats food, browns, clarifies liquids
Syneresis (weeping)
liquid released from a coagulated product
occurs when cooked at too high a temperature, or too low a temperature for too long a time; creates a tough, watery product
Egg-leavening
depends on amount of air beaten in an retained
1. when an egg foam is heated, air expands, egg white stretches and protein coagulates
2. acid stiffens egg white foam by tenderizing protein allowing it to stretch more easily (egg white foams compared by measuring specific gravity)
3. egg whites at room temperature have lower surface tension-whip more easily and yield larger volume
4. Sugar stabilizes egg white foam
Egg-emulsification
- lecithin helps yolk act as an emulsifier
- lipoproteins stabilize the emulsion by interacting at the surface of the oil droplets to form a layer
- mayonnaise-food emulsion stabilized by egg yolk
Methods of cooking egg-water preparation
- poaching or coddling-use high quality egg, appearance is important
- vinegar and salt improve shape by hastening coagulation
- surfaces of yolks turn green when overcooked or allowed to cool slowly due to iron from yolk and sulfur from whole egg combining to form ferrous sulfide
Methods of cooking egg-dried heat
- overcooking toughens
- undercooking results in excessive shrinkage when removed from oven
Methods of cooking egg- custards
- larger the % sag, the more tender the gel (objective measure of quality)
- custards made from dehydrated eggs, may be grayer and less yellow, have an eggy flavor, and be watery
Egg processing-frozen
- remove from shell first; can be frozen whole or in parts
- 10% salt or sugar (by weight of the yolks) are added as stabilizers
Egg processing-dried
- can be vacuum-packed in nitrogen gas
- dried fortified: 70% white, 30% yolk
- baker’s special eggs: sucrose added to improve foaming ability
Egg substitutes
- lower in fat, calories, cholesterol; often higher in sodium than fresh eggs
- when cooking with egg substitutes, there will be color (added carotenoid) and flavor differences
When eggs are held in the refrigerator too long:
- deterioration affects appearance and use
- loss of carbon dioxide makes eggs more alkaline
- whites become watery, yolks flatten
- odors are absorbed
Milk composition and nutritive value
- 87% water, 3.7% fat, 4.9% carbohydrate (lactose)
- 3.5% protein (complete, HBV); 80% casein (precipitated at pH 4.6 forms soft curd); whey is liquid that drains from curd (lactose, lactalbumin, lactoglobulin, water soluble vitamins, minerals)
- good source of calcium, phosphorous, riboflavin, vitamins A, D
- low in iron and vitamin C
Pasteurization
- destroys pathogenic bacteria
- 145F for 30 minutes or 160F for 15 seconds
- UHT (ultra high temperature) aseptically packaged milk can be stored without refrigeration if unopened
Types of milk: homogenized
high pressure breaks fat globules to 1/5 regular size; film of protein surrounds each globule
Types of milk: vitamin D milk
feed the cow vitamin D, irradiating the milk, or adding vitamin
Types of milk: 2%, low fat, skim
2% milk has 1.5-2.25% fat
low fat milk has .5%-2% fat
skim milk <.5% fat
Types of milk: concentrated
evaporated milk (60% water removed, at least 7.9% milk-fat, brown color due to caramelization of lactose during canning),
sweetened condensed milk (evaporated milk, add 15-18% sucrose or glucose),
dried whole milk (26% fat, does not keep well),
dried skim milk (<1.5% fat, condense skim milk, dry by spraying into heated vacuum chamber)
Types of milk: fermented
cultured buttermilk: add lactic acid bacteria to skimmed or partly skimmed milk, recipe= 1T vinegar or lemon juice, or 1 3/4 tsp cream of tartar + enough milk to make 1 cup, when using buttermilk in place of regular milk increase baking soda
sweet acidophilus milk: skim milk + Lactobacillus acidophilus bacteria to reduce lactose
Types of milk: fermented
cultured buttermilk: add lactic acid bacteria to skimmed or partly skimmed milk, recipe= 1T vinegar or lemon juice, or 1 3/4 tsp cream of tartar + enough milk to make 1 cup, when using buttermilk in place of regular milk increase baking soda
sweet acidophilus milk: skim milk + Lactobacillus acidophilus bacteria to reduce lactose
kefir: fermented by Lactobacillus kefir which reduces lactose
Types of milk: low lactose-Lactaid
treated with lactase in processing or add enzyme to regular milk and hold in the refrigerator
Types of milk: yogurt
coagulated product, fermentation of milk sugars by lactic acid bacteria
Types of milk: filled milk
skim milk, vegetable fat (coconut oil), water, illegal in some states
Types of milk: imitation milk
resembles milk but contains neither milk fat nore other important dairy ingredients
made from casein derivatives or soybean protein and vegetable oils
When milk is heated, whey protein:
precipitates out on bottom of pan or on surface of milk
To prevent a film from forming when heating milk
cover or beat the milk to produce foam
To prevent milk from coating sides of pan
heat over water
To prevent curdling
add acid slowly and agitate, acid precipitates casein
Butter vs margarine fat percentage
butter- 80% milk fat; margarine- 80% vegetable oil or animal fat
Hydrolytic rancidity
Uptake of water leads to flavor changes in butter (saturated fat)
Oxidative rancidity
Uptake of oxygen at a double bond in an unsaturated fat
Cream % fat
heavy or thick >36%
medium 30-36%
whipped cream 35%
light or thin 18-30%
sour cream >18%
half and half no less than 10.5%
Cheese production
warm milk, add lactic acid bacteria, add enzyme rennet to coagulate casein forming th curd, separate curd from whey
Cheese types
- uncured-refrigerate immediately (cottage cheese, cream cheese)
- cured- additional whey removed, salt added, ripened
- % moisture content high to low: cottage (79), cream, mozzarella (45-55), camembert, bleu, Swiss, cheddar, parmesan (31)
- processed- blend of several natural cheeses + emulsifier, fat will not separate out, high moisture content (41-50%)
To prevent stringy, curdled-looking cheese products
cook for short time at moderate temperatures
Flour, grains, and cereals: structure
starchy endosperm rich in protein, outer layer of hull, and bran
scutellum in germ has most thiamin
Flour, grains, and cereals: nutritional value
75% starch; partially complete protein; 2% fat-found in germ
vitamin E (in germ), thiamin, riboflavin, phosphorous
Flour, grains, and cereals: milling
air classification is a separation method that improves baking qualities by separating large flour particles from fine particles
Flour, grains, and cereals: processing of hot, ready to cook cereal
- farina-inner portion of wheat kernel
- quick-cooking cereals have disodium phosphate added: makes cereal alkaline so particles swell faster, avoid on low sodium diets
- enzyme treated for quicker cooking means the proteins have been split to lessen cooking time
Wheat flours: graham, whole wheat
entire grain, use freshly ground, spoils quickly due to fat in germ
Wheat flour: bread (hard wheat)
strong gluten; 11.8% protein
Wheat flour: all-purpose
blend of hard and soft, less gluten, 10.5% protein
Wheat flour: pastry (soft wheat)
weaker gluten, 7.9% protein
Wheat flour: cake (soft wheat)
least and weakest gluten, 7.5% protein
Wheat flour: enriched
thiamin, riboflavin, niacin, iron, folic acid
Wheat flour: instant blending, agglomerated, instantized
no pre-sifting needed
Wheat flour: self-rising
baking powder, flour, and salt
Alimentary pastes
- durum wheat-high in gluten: after bran and germ removed, starch is ground to make semolina flour, products are flexible after cooking
- noodles- contain egg yolk or egg solids
Rice cookery
- vitamins are lost when cooked in excess water or when water is drained off
- cook in an amount of water that will be absorbed during cooking (for 1 cup rice-use 2 cups water)
Functional properties of gluten (flour) in baked goods
elastic properties, forms framework, holds in leavening agent, made from gliadin and glutenin through process of hydration and mixing
strength of flour refers to capacity to retain leavening
Color due to carotenoids in baked flour mixtures
- natural agents cause oxidation during storage and turn flour from creamy yellow to white
- if an oxidizing agent is added-labeled “Bleached”
What happens to baked goods when you add bran and how do you compensate?
- decreases volume of end product
- increase flour and liquid to compensate
Functional properties of liquid in baked goods
hydrates gluten and starts its development
starts action of chemical leavening agent
dissolve salt, sugar; gelatinizes starch
Functional properties of leavening agent (steam) in baked goods
expand the hollow shell formed by flour and egg
hot oven is required to raise liquid to boiling quickly
popovers, creampuffs
Functional properties of leavening agent (air) in baked goods
air expands when heated before proteins coagulate and retain it
to incorporate air: beat, sift, fold, cream
angel cake, sponge cake
Functional properties of leavening agent (carbon dioxide) in baked goods
from action of yeast on sugar yielding carbon dioxide and alcohol
from action of acid (sour milk, cream of tartar, molasses) on baking soda (sodium bicarbonate)
baking powder (mixture of baking soda, dry acid, and cornstarch) provides both the acid and alkali needed for reaction; old baking powder is more alkaline causing loss of thiamin in baked goods
deeper brown crust: alkaline solution (baking soda) and solid sugar
Functional properties of salt in baked goods
adds lavor, keeps yeast from sticking
Functional properties of egg in baked goods
provides stability, retains leavening agent, distributes shortening by emulsification, introduces air, adds color and flavor
Functional properties of fat in baked goods
adds tenderness by coating gluten particles
Functional properties of sugar in baked goods
hygroscopic-tenderizes; softens gluten and prevents gluten development by absorbing some of the water gluten needs
too much sugar results in coarse cells, thick walls, a shiny crust and a crumbly product
most of sugar in honey is glucose and fructose
when substituting Sweet and Low for sugar in a recipe, use half as much
Methods of mixing
- use bowl with sloping sides and 1/2 full
- beat: over and over to smooth and incorporate air
- cream: work one or more foods until soft and creamy (cream fat into sugar)
- cut-in: distributes fat into dry ingredients
- fold: use in foams; a down, across, up, across the top motion, rotate bowl
- knead: used in dough; push, pull, turn
- stir: circular or figure 8 motion to blend
- whip: beat rapidly to incorporate air to form a foam
Quick breads, examples
muffins, biscuits, popovers
Quick breads, basic ingredients
egg and flour
Muffin mixing method
- sift dry ingredients; make well in center
- blend liquids and add all at once to dry ingredients
- mix just enough to dampen
Excess mixing of muffins results in:
- loss of carbon dioxide, overdeveloped gluten
- tunnels from top to bottom, tough, heavy produce
Characteristics of a good muffin
round, pebbled top, symmetrical shape, no long, narrow tunnels
Cakes-method of mixing
cream fat with sugar, add egg, add sifted dry ingredients in portions, alternating with portions of milk
Cakes-types
shortened cake (comparatively large amount of fat; uses chemical leavening)
foam cake (uses air as leavening)
Types of shortened cake
- layer cake (baking powder)
- pound cake (air and steam)
- rich cake (increased fat, sugar, egg; increases keeping quality)
- gold cake (egg yolks)
- white cake (egg whites)
- yellow cake (whole egg)
Types of foam cake
- angel cake (egg white foam)
- sponge cake (yolk foam and white foam)
- chiffon cake (liquid yolks, egg white foam, baking powder, oil)
Crumb structure depends on:
ingredients, procedure used, pan shape and size, baking temperature, time elapsed before baking
Cake-alterations in the amount of sugar
the more sugar, the more time is needed to reach the elevated coagulation temperature of the gluten
As sugar increases, the volume of cake increases up to the point where volume is so great, and gluten so weak, that the gluten strands snap and the cake falls in the center
gummy, crystalline appearance
What causes a cake to yellow?
alkaline batter (excess soda)
What causes a cake to have a fallen center?
excess sugar, excess fat, excess baking powder
What causes a cake to have a tough, dry crumb?
too much flour or egg, too much mixing, too little fat or sugar, over-baking
What causes a cake to have a coarse texture?
too much baking powder or sugar, oven temp too low
What causes a cake to have poor volume?
too little baking powder, improper level of sugar or fat
Cookies
modified shortened cake; higher in fat, lower in sugar and liquid
Pastry
flour, fat, liquid, salt
Substituting butter for lard in pastry
lard and oil are each 100% fat; butter and margarine only 80% fat
when substituting butter for lard, need to use more
Pastry, mixing method
cut fat into flour and salt, add liquid
avoid over-handling
bake at 425-250F for 10-15 minutes
How do you increase tenderness in pastry?
enhance by using oil, soft fats, or fat cut into very small pieces
How do increase flakiness in pastry?
leave fat in coarse particles (fat pieces melt and leave a hole where steam collects)
How do you bake meringue on top of lemon pie?
spread meringue on warm to hot filling, bake at 425F 4-5 min
Liquid to flour ratios of: pour batter, drop batter, soft dough, stiff dough (and examples)
pour batter 1:1, waffles
drop batter 1:2, muffins
soft dough 1:3, bread
stiff dough 1:4, pie crust
What type of batter absorbs the most fat when deep fried?
high fat, high sugar
What types of flour absorb less fat during frying?
all-purpose and bread flours absorb less fat than cake flour
Yeast dough
- use high protein flour (low protein flour causes crumbly products)
- yeast ferments sugar releasing carbon dioxide
Straight dough method-yeast dough
all ingredients are added before dough is allowed to rise
Sponge method-yeast dough
combine liquid and part of flour and allow to ferment for several hours; add other ingredients and knead
proofing time is shortened
Continuous baking method-yeast dough
reduces processing time, not as affected by fermentation time and temperature
commercial process that substitutes intense mechanical energy to a large degree for traditional bulk fermentation
Baking at high altitudes
- steam forms earlier
- decrease amount of baking powder, increase amount of liquid
- longer cooking time required (boiling temperature drops 1F for every 500 foot rise)
Two types of starch molecules
amylose and amylopectin
Amylose
responsible for gelation of cooled, cooked pasta
not branched
Amylopectin
branched: 1,4 and 1,6 alpha glucosidic linkages
waxy starches (corn, rice, sorghum)
non-gelling: stable to freezing and thawing, used in frozen foods (corn starch used most often)
Thickening ability of starches in order of effectiveness (most to least)
potato, waxy corn, waxy rice, waxy sorghum, tapioca, wheat starch, wheat flour
(wheat flour less effective than wheat starch because of protein content; more protein=less effective)
Gelatinization
the swelling that occurs when starch is heated in water close to boiling point.
Heat dissociates bonds, water moves in and swells granules.
Friction is created causing paste to thicken
Role of sugar in gelatinization
- competes with starch for water
- increase translucency, reduces viscosity and gel strength
- if too much sugar is used, consistency is thin
Acid effect on gelatinization
breaks down starch producing runny product
if necessary, add when cooking is complete
Retrogradation
starches revert to insoluble form on freezing or ageing, hydrogen bonds holding gel together break causing gritty texture
stale bread, separation of when gravy thaws
more common with higher proportion of amylose
Modified starch
chemical modification: by acids and enzymes to change viscosity and ability to gel
physical modification: pre-gelatinized starch used in instant pudding
used to stabilize frozen gravies, waxy maize, modified cornstarch
Starch uses in food preparation-dry heat
starch molecules break into fragments called dextrins-dextrinization
color change occurs (browning of toast)
Starch uses in food preparation-moist heat
- starch granule in cold water don not dissolve, form a suspension
- to prevent lumps, mix starch with fat, cold water, or sugar
- heat, acid, and agitation will affect the stability of swollen starch granules in a paste
White Sauce
- melt fat, add flour (roux-half fat, half flour)
- remove from heat, add liquid at 170-180F; add salt
- add an acid when cooking is complete
- to get a clear, shiny, translucent sauce, use cornstarch as thickener
- if product is starchy tasting and grainy-due to uncooked flour
- souffle is an example of a thick white sauce
Crystallization in food preparation-preparation of crystalline candies
heat sugar and liquid to dissolve. heat further. crystallize under conditions that produce small crystals which have a smooth, creamy feeling
How to control crystal size-crystal inhibitors
(keep crystals small and smooth)
1. Acid-cream of tartar, vinegar
-sugar and acid combine to promote inversion (hydrolysis) of sucrose
-end products are equal amount glucose and fructose (invert sugar)
2. fat-chocolate, milk
3. protein-milk, egg whites, gelatin
Candies-ingredients
sugar, water, corn syrup or cream of tartar
Candies-progression of look and texture
viscous, shiny and smooth at start of process then becomes creamy, dull, lighter in color. With further beating, cools and stiffens rapidly
Candies-types
- crystalline sugar-fixed orderly pattern of molecules or atoms (large crystals-rock candy; small-fondant, fudge)
- non-crystalline sugar- amorphous, glasslike (crystallization prevented with interfering substances or increased sugar concentration; hard candies, brittles, chewy candy, gummy candies)
Ice cream-overrun
increase in volume from freezing and whipping
determined by weight; should be 70-80%
Ice cream-homogenization
makes ice cream smooth by making it easier to beat in air during freezing
Ice cream-agitation
is essential to keep ice crystals small and to incorporate air
Process for making ice cream
hydrate gelatin in cold water then heat
Ice cream- crystal inhibitors
- fat- not adding enough fat produces a grainy texture, increase fat to produce smoother ice cream (heavy cream instead of light cream)
- egg
- gelatin
- nonfat milk solids
Mellorine
imitation ice cream; butterfat replaced by hydrogenated vegetable oil
Gelatin-nutritive value
4 calories/gram; incomplete protein-no tryptophan, low in methionine and lysine
Gelatin-properties and uses
- changes liquid into elastic solid
- acts as a foaming agent in marshmallows
- keeps sugar and ice crystals small in candy and ice cream by interfering with the union of small crystals to make large ones
Gelatin-gel formation
1 T gelatin will gel 1 pint liquid, mix with cold water to soften, add hot water to disperse
Increase gelatin or decrease liquid when:
- making a large mold
- it will stand at room temperature for a long time
- acid content is high
- making a whip
Enzymes that prevent gelation
bromelain (pineapple) and papain (papaya)
What temperature is best for brewing coffee
185-203F; higher temperature-tannin is extracted and coffee is bitter
Percolator
single container, covered basket with stem; gives stronger and bitter coffee; water is hotter and repeatedly passes through grounds
Dripolator
three separate compartments; add boiling water to top and let drip through; brief contact with ground; free of bitterness
Vacuum brewed
higher temps than recommended
Decaffeinated coffee
process uses methylene chloride
Food additives
FDA controls
emulsifiers, sorbitol, stabilizers/thickeners, anti-caking, nitrites, mold inhibitor, antioxidants, flavor enhancer
Examples of emulsifiers
- monoglycerides
- diglycerides
- lecithin
- disodium phoosphate
Reasons for adding sorbitol
humectant (retains moisture)
sweetener
bulking agent
limits mold
Examples of stabilizers/thickeners
pectin
cellulose
gelatin
gum
agar
carrageenan-prevents chocolate from sedimenting in fat free milk
Examples of anti-caking
Calcium silicate
mannitol
Reasons for adding nitrites
fixes color
inhibits spores of clostridium botulinum
Examples of mold inhibitors
propionate
sodium benzoate (soda)
Examples of antioxidant additives
propyl gallate
BHA
BHT
ascorbic acid
alpha tocopherol (natural)
Examples of flavor enhancer additives
MSG-monosodium glutamate (provides umami, savory taste)
Qualitative sensory evaluation of food
uses organoleptic measurements (sense organs) to test color, odor, taste, texture
Analytical sensory evaluation of food
difference or discrimination tests
-paired comparison test- two samples side by side to compare specific quality
-triangle- three samples, determine which two are identical, tests differences between new and old products
-ranking or scaling- classify differences in color, taste; rank in order of preference
Affective sensory evaluation of food
determine preference, acceptance, or opinions of a product
-hedonic rating-scale; facial hedonic-smiling faces
-paired preference-compares two samples for preferences of a specific attribute
-ranking test-extension of paired preference; additional samples
Flavor profile method of sensory food evaluation
trained panel
analyze and record aromas and flavor in great detail
Pentrometer
tenderness firmness; baked custards (objective measure)
Viscosimeter
objective measure of viscosity on an incline plane or rotational basis
Line-spread test
objective measure of viscosity on a flat surface
Specific gravity
objective comparison of lightness of products (egg white foams); ratio of the density of a food to that of water
GMO
scientific techniques used to produce specific desired traits in plants, animals, or microorganisms through the use of genetic knowledge
GMO crops
corn, soybeans, canola, papaya
GMO results include:
plants more resistant to disease, insects, weeds
plants that require less water
extended shelf life
improved efficiency of food production
Food synergy
the additive influence of foods and constituents which, when eaten, have a beneficial effect on health
Probiotics
live microbial food ingredients that benefit health (kefir, acidophilus milk, yogurt)
promote healthy microbial balance in intestine, may stimulate activity of immune cells and reduce gut inflammation
Prebiotics
nondigestible food ingredients that support growth of probiotics
1. fibers (FOS, soluble dietary fiber, found in onions, garlic, asparagus)
2. inulin (fructose polymer)
Functional foods
provide more functions than the basic nutritional benefits
1. conventional (whole) foods
2. modified: fortified, enriched, enhanced
3. medical foods: PKU formulas
4. special dietary use: gluten-free, weight loss foods
Phytochemicals
biologically active, naturally occurring chemical components in plant foods, act as natural defense for plants
Sources of phytochemicals
fruits, vegetables, legumes, whole grains, nuts, seeds, herbs, and spices
Possible benefits of phytochemicals
- prevention or treatment of chronic diseases
- may detoxify drugs, toxins, carcinogens, mutagens
- may act as blocking agents, preventing active carcinogen from reaching target
- may reduce risk CHD by protecting LDL cholesterol from oxidation, reducing synthesis or absorption of cholesterol
Examples of phytochemicals
- Indoles: cruciferous vegetables (sulfur)-detoxification of carcinogens
- Isoflavones: anthoxanthin in soybeans- lower elevated cholesterol
- categories: terpenes, carotenoids, lycopene, phenols, flavonoids, phytoestrogens, thiols, lignans (flaxseed)
USDA National Nutrient Database for Standard Reference
major source of food composition
FNDDS Food and Nutrient Database for Dietary Studies
use to analyze data from dietary studies
FDA Total Diet Study Database
Data on foods, minerals, chemicals
Dietary supplements database
NIH
Labeling and packaging claims
Nutrition Labeling and Education Act
FDA
label must identify: form, weight, name and address of manufacturer, ingredients in decreasing order of predominance, size of serving
Label regulations
low cholesterol= <20 mg of cholesterol/serving
low calories= no more than 40 calories/serving
calorie free= <5 calories/serving
low fat= 3g or less/serving
fat free= <0.5 g/serving
very low sodium= no more than 35 mg/serving
low sodium= no more than 140 mg/serving
low sat fat= 1g or less/serving
lean= <10g fat, <4g sat fat, <95mg cholesterol
extra lean= <5g fat, <2g sat fat, <95mg cholesterol
free= no amount, or trivial amount
lite, light= 1/3 fewer calories or 50% less fat
gluten-free= <20ppm
organic= minimum of 95% organic ingredients
Label regulations
low cholesterol= <20 mg of cholesterol/serving
low calories= no more than 40 calories/serving
calorie free= <5 calories/serving
low fat= 3g or less/serving
fat free= <0.5 g/serving
very low sodium= no more than 35 mg/serving
low sodium= no more than 140 mg/serving
low sat fat= 1g or less/serving
lean= <10g fat, <4g sat fat, <95mg cholesterol
extra lean= <5g fat, <2g sat fat, <95mg cholesterol
free= no amount, or trivial amount
lite, light= 1/3 fewer calories or 50% less fat
gluten-free= <20ppm
organic= minimum of 95% organic ingredients
%DV
% of the daily value for each nutrient a serving of the food provides, based on a 2000 calorie intake.
Includes DRV (daily reference value) and RDI (reference daily intake)
New food labels
DVs for vitamin D, potassium, calcium, iron; total sugar and added sugars; single serving packages reflect values as one serving
Food additive that does not have GRAS status
sucralose
Packaging claims
Health claims: based on authoritative statements from a scientific body of the US Government or the National Academy of Sciences
Qualified health claims
emerging evidence of a relationship, but not conclusive; requires a disclaimer
Structure function claims
may be used without FDA permission
Ineffective communication can result in incorrect diagnoses and noncompliance with treatment. Consider the following:
- Assume differences until similarities are proven
2.Emphasize description rather than interpretation or evaluation. Focus on getting a complete description of what is wanted rather than making judgments on how something was said. - Avoid stereotyping
How do cultural communication styles differ?
- Rate, pitch and volume of the voice
- Eye contact: direct gaze or avert eyes as a sign of respect
- Expression restrained, emotional, focused
- Speech: slow and soft, loud and fast
- Greetings: handshake firm, mild
Spatial relationships vary among cultures and among individuals, what are the zones?
- Intimate zone: <18” very close friends, business handshakes
- Personal zone: 18”-4’ giving instructions, working closely
- Social zone: 4-12’ most business interactions
- Public zone: >12’ very formal interaction
When working with clients with limited English:
use common terms
avoid slang, acronyms, and shorthand
use short, simple sentences
Pedagogy
art and science of teaching children
teachers are authority figures
Andragogy
adults are mutual partners in learning, more problem-centered than subject-centered, motivation is more internal than external, self-directed learner
Social Economic status effect on learning style
Middle and upper adults: goal-oriented; consider activities they can’t relate to as a waste of time
Lower income adults: interests focus on costs and traditional food habits; oriented toward present and towards solving current problems
Very Poor: short term planners
Age groups learning styles
Adolescents: relate to their interests; consider peer pressure and attitudes toward authority
Elderly: decreased attention span; audience participation to maintain interest; control questions to stay on topic; prefer written material
SMART objectives
specific, measurable, attainable, relevant, time bound
Consonance
the fit between the program and the expected outcomes based on the objectives
Content: community resources, learning activities/methodology, references, handouts, instructional materials
- evaluate the information available and match it to objectives
- organize into logical sequence
- develop a lesson plan
- evaluate what you have developed
Instructional media selected depends on:
teaching goals
size and learning style of the audience
physical facility
equipment and time available
Posters, slides, movies
assist in oral instruction
Computers, programmed instruction materials
can substitute for instructors in certain aspects of the learning process
used to learn purely cognitive material; leaves instructor more time to develop affective and psychomotor learning
Evaluation criteria
- What is the purpose, timing, and the specific outcomes? What will you valuate, when and how?
- Evaluation strategies should reflect the objectives of the educational program.
-norm referencing compares students with the norm of a group
-criterion referencing measures performance against a standard or defined objective
Budget development
- Budgeting is closely linked to planning. Account for all expenses
- Consider project funding, expenditures to date, current estimate costs to complete the project, anticipated profit or loss
- Periodic budget reviews help control resources and help adhere to the planning schedule
Tools of program promotion
advertising: purchased print or electronic media. Targeted message to carefully defined audience
sales promotion: short term incentives to encourage purchases (coupons)
personal promotion: formal/informal presentations, health fairs, cooking demonstrations, media interviews. Direct contact provides positive feedback
public relations (publicity): organized effort to promote a favorable image through news coverage or goodwill
Types of domains of learning
- cognitive: acquisition of knowledge or subject matter (factual information)
- affective: acquisition of attitudes and values, growth in feelings or emotions
- psychomotor: acquisition of muscular skills (exercises, food preparation)
Bloom’s taxonomy
objectives at lower level must be mastered before more complex learning can take place
Education readiness assessment: Motivational level
affects attention span
Education readiness assessment: Educational level
not always related to amount of formal education
Education readiness assessment: situational assessment
Inexperienced: young children, some adults lacking nutrition training, need thorough introduction and background
Moderately experienced: teachers, health educators, patients already instructed. Emphasize review of material, reorganize it for better use, move on to more complicated concepts
Very experienced: limit audience participation at first, establish yourself as the expert, cite credentials, lecture format/AVs
economics, time needed, availability, environmental
Behavior modification
techniques are based on a cause-and-effect explanation of behavior
ABC framework: therapy can focus on Antecedents, Behavior, or Consequences
Behavior modification methods
- positive reinforcement: encourages repetition of a given behavior; specific and immediate; meaningful attention from superiors
- avoidance learning: learn to escape from unpleasant consequences, avoid future criticism by improving future performance
- extinction: reduce undesired behavior; ignore undesired behavior
Transtheoretical Stages of Change model
Precontemplation: unaware/not interested
Contemplation: thinking about change
Preparation: decides/plans to change
Action: tries to make change
Maintenance: Sustains change for >6 months
Health Belief Models
developed to explain why people fail to participate in programs designed to detect or prevent disease
person must perceive severity and their susceptibility to the threat for threat to be behavior-motivating
Health Belief Model Components
Perceived susceptibility
Perceived impact
Perceived advantage of change
Appraisal barriers
Self-efficacy
DIffusion of innovation: categories of people
Innovators: adopt and idea readily without input from others
Early adopters: opinion leaders in community, well respected
Early majority: cautious in adopting new ideas
Late majority: skeptical, adopt an idea only through peer pressure
Laggards: last to adopt the idea
Diffusion of innovation: components
knowledge, persuasion, decision, confirmation
Communication principles
- motivation eases transition to new behaviors
- emphasize human factors; feelings, anxieties, concerns
- involve learner in an active way; application of the info and active involvement of the learner permits the greatest retention
- establish rapport
- discuss problems descriptively rather than evaluatively; don’t be judgmental
- offer alternatives provisionally rather than dogmatically
- problem-oriented rather than manipulative
- empathetic rather than neutral
message should be clear, complete, concise, concrete, correct - listening: clarification, active listening-paraphrase
10 legitimation statements
How to instruct
prepare, present, try, follow-up
Environment for instruction
- psychological-openness, encourage questions, informal, supportive
- physical-comfortable temperature, lighting, chairs; maintain eye contact; free from outside noise
- confidentiality must be respected
Method of instruction is based on the size of the group and the educational and motivational aspects of the group’s members
- the discussion method of teaching helps master higher-level cognitive objectives: small group discussion-some lecture plus interaction; beneficial in clinical setting; teacher needs to remain in control; 3-5 people with similar needs; learn from each other
- large group-lecture: one way flow of information; presents a large amount of material in a short time
Group process, group dynamics: skills to develop as a group leader
- relieve social concerns of the group; all must feel accepted
- tolerate silence-after introductions, state purpose of gathering, state your intentions not to participate, sit patiently
- guide and encourage interactions; don’t become focus
- know when and how to resume control
- reinforce “multi-sided” nature of conversation; “how do you feel about that?”
- exercise control over talkative participants; encourage silent members
- halt side conversations by engaging the distractors; discourage wisecracks
- help group stay on topic; avoid showing your preferences
- negotiating techniques- plan strategy in advance-know what you are willing to accept; don’t start with the hard issues; be direct, clear, calm, patient, tolerant
- synergy: the groups product (decision) is superior to what the most resourceful individual within the group could have produced by working alone
Interviewing: steps
- preparation: collect background information-age, weight, height, diet history; establish objectives for collecting information during the interview
- build rapport
- collect data: open-ended, non-judgmental questions
- closing: summarize for client to check accuracy; tell client what will be done with the information and when he will be contacted for teaching
Question types
open-ended: broad, gives freedom in responding; gives you a chance to listen and observe; takes more time but less threatening
closed: more restrictive; limits answers; gives you control; less time
primary: introduces new topics
secondary: obtain more info, follow-up
neutral: preferred-do not reveal your bias
leading: reveals your bias
Non-verbal communication
- kinesics: physical communication
-direct eye contact-attentiveness
-lowering eyes, look away-preoccupation
-arms folded across chest-dislike, avoidance
-clenched fists-anxiety, anger
crossing and uncrossing legs-anxiety - paralinguistic: how the client’s message is delivered
-hesitations, stuttering-sensitivity, anxiety
-whispering-difficulty disclosing - proxemics-personal space
-moves away-discomfort
-moves closer-seeking more interaction
-sits behind or next to an object-seeks protection
Strategies when delivering culturally diverse nutrition counseling
- listen first to assess prior knowledge
- reinforce correct knowledge, clarify misinformation
- use simple language, use visual media to show what you are teaching
- talk in slow, clear words, repeat as necessary
- encourage questions and strive for interaction
- use the teach-back method-ask client to restate knowledge in own language
Counselor’s responses to client: evaluative
make judgment about persons feelings, or imply how he should feel. Leads to offering of advice, not problem-solving, seldom helpful
Counselor’s responses to client: hostile
uncontrolled anger or frustration; may antagonize or humiliate client
Counselor’s responses to client: reassuring
may make it difficult to solve the client’s problem or discuss it further. suggests the problem does not exist. client is prevented from working through feelings. little attempt is made to understand the needs of the client
Counselor’s responses to client: probing
attempt to clarify or gain more information as they recall details. may encourage conversation
Counselor’s responses to client: understanding
one of the best ways to respond, try to recreate the persons message in your own frame of reference. may lead to more client cooperation. helps client feel accepted and safe in expressing their feelings
Cognitive Behavior Theory
focus on identifying behaviors and thoughts that have a negative impact on desired behaviors and goals and apply strategies to change those thoughts
Motivational Interviewing
It is a client-centered method for enhancing intrinsic motivation, guides rather than directss, and does not give advice to the client
Motivational Interviewing strategies
- Express empathy (suggests acceptance), evocation (summons feelings)
- Develops discrepancy-between where he is and where he wants to be
- Avoid arguments and confrontation
- Roll with resistance-acknowledge reluctance to change and ambivalence; offer new information or alternatives to consider
- Support self-efficacy-reinforce hope and optimism
- Client autonomy means that decisions are left to the client
Methods of communication: written
more formal and authoritative: email, texting, handouts
1. interpreted more accurately-use when record is required
2. keep reading level around 8th grade for general population and 6th grade for low literacy audiences
3. procedure for determining readability: SMOG Index gives grade level of written text by determining average number of polysyllabic words
Methods of communication: verbal
more personal, encourages two-way communication
most critical barrier: poor listening skills
Methods of communication: media activities
- develop media partnerships with local television and radio stations: extends reach to audiences that maybe out of reach due to financial reasons
- introduce campaign to the community with kickoff events (press conference at farmer’s market, grocery store), develop 2-4 key messages
- sustain ongoing media relationships with a few key reporters who cover food or health issues offer to serve as resource for them
Formative evaluation
made early or during course of education, can change direction
1. helps pinpoint parts mastered and parts not mastered
2. allows for revision of plans and methods to improve the process
3. answers “How should we do it?”
4. client must be involved; focus group, pre-test, pilot test
5. frequent feedback of results guides the rest of the educational process
6. often qualitative with data collection by observation, interviews
Summative evaluation
designed at planning stage but conducted at end
1. considered final; purpose may be grading, or evaluation of progress
2. Did we achieve what we planned? What was the impact, the outcome?
3. example: post-test
4. have client perform a task using new information
5. purpose is to improve a program’s delivery and effectiveness. Did is result in desired changes?
6. uses quantitative approaches to appraise results, outcomes, or quality
Formal vs Informal evaluation
Formal-objective test: not well suited for clinic or community setting
-performance test: client asked to complete task based on learning objectives
Informal-unstructured observation of food selection and behaviors
Documentation
- Documentation of employee education and training is essential for safety issues and the correct use of all equipment
- Use orientation checklist. Note date and content of training
- The Joint Commission requires documentation of nutrition services to evaluate MNT and for any legal issues that may arise
Nutritional informatics
the intersection between nutrition, information and technology. use of technology in spreading information
Technology drives change in the practice of Dietetics
EHR, EMR, PHR
EHR-electronic health records, EMR-electronic medical record: enter, store, retrieve and manage information related to health care
PHR-personal health record: consumer maintains health information
HIPAA
maintains privacy of PHI (protected health information).
Patients’ rights to their own health information, privacy and confidentiality.
Patients must be notified if their medical information is to be shared outside of the care process, or if protected information (address, email, income) is to be shared.
Telehealth services
use of electronic information and technologies to support long-distance clinical health care, patient and professional education, public health administration, remote patient face-to-face services, via live video conferencing, store and forward telecommunication services (clinical data, images, sound, video) which can then be retrieved by another site for clinical evaluation.
Telenutrition
RDN uses electronic information and technologies to implement the NCP with clients at a remote location within provisions of their state license as applicable. Medicare Part B allows some services provided by RDNs to be offered via telehealth including MNT, diabetes self-management training
ANDHII
Academy of Nutrition and Dietetics Health Informatics Infrastructure
tracks nutrition care outcomes and advances evidence-based nutrition practice research. On-line data collection uses familiar terminology. (DOR) Dietetics Outcomes Registry aggregates anonymous data available for outcomes research
Altmetrics
presentation of amount of activity from Twitter, Facebook, science blogs, mainstream news and other sources over time
NCP National Consumer Panel
data helps manufacturers understand consumer preferences on specific brands; enables retailers to stock the right item assortment for their local markets
Three branches of government
- Legislative: introduce and enact a law, override veto by the executive branch
- Executive: may veto legislation or sign it into law
- Judiciary: may discard law if it considers it in violation of a person’s basic rights and freedoms
Operating and enforcement agencies that carry out the law
- FTC: Federal Trade Commission, regulates content of food ads, enforces truth-in-labeling, challenges product claims when product crosses state lines
- FDA-ensures safety of some domestic and imported food products
- FCC-Federal Communications Commission, licenses radio and TV
Stages of Public policy and legislation
- Legislation enters as a bill or a resolution
- The bill is sent to committees which schedule public hearing where testimony is taken from bill’s sponsors. Nutritionist can present views here or in earlier planning stages
- The committee revises bill during a markup session and put into final form. If approved, it is sent to Rules Committee for debate
- It needs approval from both Houses (House of Representatives and Senate) and the President
- Differences between the two Houses are worked out in a Joint House-Senate Conference Committee, ultimately passing a reconciliation bill
- Appropriations bill must be passed to provide funding
- formulate regulations that interpret and operate the law
-a federal regulation interprets a law and provides details and rules that put the policy into effect; carries the force of a law but is easier to change
-regulations are written by staff members of the agencies charged with enforcing the regulations
Federal Register
notices of public hearing, proposed and final rules, agency decisions, published weekly; lists changes in USDA food programs
Congressional Record
information from floor, NO HEARINGS lists bill with sponsors and action, issued daily when Congress is in session
Congressional Index
weekly update; identifies bill with sponsor and committee
Advocacy
aggressive form of action; plead cause of a group
1. know facts and arguments for and against the issue
2. be realistic-usually results in compromise
3. lobbying-activities aimed at influencing public officials and legislators
Child Nutrition Reauthorization
covers NSLP, SBP, CACFP, SFSP, SMP, WIC
The Farm Bill
covers national and international nutrition education, research, funding
The Older Americans Act
funds nutrition programs in the community
Steps in research
- identify a relevant and important topic: review published research literature related to the topic
- Develop well-considered research question
- Research question leads to a hypothesis
- Prepare research protocol: methodology to solve the problem
- Organize methods and materials, collect and analyze data
- Study results and make decisions
- Study design and checklists
Hypothesis should be:
feasible, interesting, novel, ethical, and relevant
Meta analysis
combines the results of numerous small studies to increase the strength of belief in the observed effects
Studies are of similar design, have defined inclusion and exclusion criteria, and are published peer-reviewed studies
QUOROM
has proposed quality standards for the review and monitoring of systematic reviews and meta-analysis of randomized trials
PRISMA
evidenced-based minimum set of items for reporting in systematic reviews and meta-analyses. focuses on the reporting of reviews evaluating randomized trials, but can also be used as a basis for reporting systematic reviews of other types of research, particularly evaluations of interventions
MOOSE
Meta-analysis of Observational Studies in Epidemiology (suggests common evaluation criteria)
CONSORT
common criteria for clinical trials
Research report
- abstract
- general introduction
- review of existing literature
- methodology
- results
- discussion
- conclusion
- implications
Descriptive vs analytical research
descriptive-describes state of nature at a point in time, generates hypothesis regarding determinants of a condition or disease, provides baseline data and monitors changes over time, establishes associations among factors, but does not allow causal relationships to be determined
analytical-tests hypotheses concerning the effects of specific factors of interest and allows causal associations to be determined
Types of descriptive research
- qualitative research-generates narrative data collected through interviews, observations, questionnaires; may use focus group-Delphi
- case report, case study, or case series-report observations on one subject or more than one subject
- surveys-research designed to describe and quantify characteristics of defined population; defined time frame; pinpoints problems
- correlation studies or ecological studies-compare frequency of events in different populations with the per capita consumption of certain dietary factors
Types of analytical research
- Experimental model-randomized control trials
- Quasi-experimental design-series of measurements at periodic intervals before the program begins and after the program ends, shows whether continued pattern or noteworthy change
- Cohort studies-cohort of healthy people with a behavior and one without a behavior followed through time to see if they develop a specific disease (incidence)
- Case control studies-those with the disease are compared with a group without the disease, but otherwise similar in characteristics
- Cross-sectional studies-one time data collection counting all of the cases of a specific disease among a group of people at a particular time (prevalence)
Parallel design research
participants are randomly assigned to a particular treatment group and remain on that treatment throughout the study
crossover design study
each participant serves as their own control, intervention-wash out period-intervention
Institutional Review Board
committee established to review and approve research involving human subjects to ensure it is conducted within all ethical and federal guidelines
AKA Independent Ethics Committee, Ethical Review Board, or Research Review Board
To be designated as an author of a manuscript in a biomedical journal
you must have made substantial contributions to the design or analysis and the interpretation of the data
Relevance or validity
ability to measure phenomenon it intends to measure
Internal validity
tests whether the difference between the two groups is real (has the experimental group really performed differently)
External validity
tests whether or not a generalization can be made from the study to a larger population
Analysis of variance
ANOVA-tool used to evaluate validity
asks whether the difference between samples is a reliable one that would be repeated
used when several products compete against one another
compares the variance between groups with the variance within groups
answers: are there one or more significant differences anywhere among the the samples
Reliability
consistency or reproducibility of test results
1. test then retest later: are the results similar?
2. parallel forms: two separate but similar forms of the same test at the same time, reliable if similar results
3. split halves: divide the test in half, reliable is similar results
Precision
amount of variation that occurs randomly
less random variation-> greater precision in the measurement and greater reliability
Sensitivity and specificity
sensitivity-proportion of afflicted individuals who test positive
specificity-proportion of non-afflicted identified as non-afflicted
Nominal variables
variables that fit into a category with no special order (gender, race, marital status, present or absent)
Rank order variables
observations compared with each other and put in order, perhaps best to worst, or state of disease from 1 to 4
Numerical discrete variables
data with numbers (number of clinics)
Dependent vs Independent variables
dependent-outcomes
independent-what you manipulate in the study
Probability sampling
each segment of the population will be represented in the sample
randomization-select sample from whole population
Non-probability sampling
no way of forecasting that each element in the population will be represented in the sample
convenience or accidental, quota
Arithmetic mean
simple average
Median
midpoint
Mode
most frequently occurring value; prediction most likely to right
Range
measure of dispersion, difference between the lowest and highest values in the distribution
Standard deviation
indicates degree of dispersion about the mean value, square root of the sum of the squared deviations of each value from the mean divided by the number of observations
68% of observations within 1 SD
95% within 2 SD
Linear correlation coefficient (r)
measures the degree to which the points in a scatter diagram cluster about a straight line
r is between -1 and 1
closer to 1 (or -1) is closer to a straight line
r=0 is no linear relationship
Clinical significance
change or difference in outcomes that somebody cares about
p-value
less than or equal to .05: significant difference, results are reliable
smaller p value the higher confidence that the effect observed is real
Double blind study
removes bias from research; neither the researcher nor the subject knows which group is receiving the treatment and which the placebo
Mortality
rate of death
Morbidity
state of disease
Variable of interest
what researchers are observing
Population of interest
describes group about which the observations are made
Descriptive statistics
summarizes and describes aspects of a set of data
Inferential statistics
techniques that allow conclusions to extend beyond and immediate data set; what is the probability that the results can be applied to a larger group; what can you infer from the results of your study
Nonparametric test
does not depend on a normal distribution
Dichotomous scores
only two events are possible (heads, tails)
Continuous scores
measured on a continuous scale
Pilot study
scaled down version of the larger investigation; practice implementation, determine whether clinical trial, as planned, is feasible; are goals realistic and attainable? includes every step in the study, but done on a small test group; formative evaluation
Focus group
method of attaining information about a target group; small group who talk about the beliefs, opinions, problems; contributes attitudinal data
Chi square
tests whether or not there is a real difference between categories
used with attributes that have more than two categories
compares frequency with which we’d expect certain observations to occur with the frequency they actually occur
t test
tests significance between the means of two different populations
histogram
block diagram whose blocks are proportional in area to the frequency in each class or group, summarizes data from a process that has been collected over time
AND Evidence Analysis Library
Evidence-based guidelines summarized by subject matter experts and trained analysts that assist in answering questions that may arise during provision of nutrition care
Energy Sources
Carbohydrates- 4 kcal/g
Protein- 4 kcal/g
Fat- 9 kcal/g
Energy Source for the brain
glucose exclusively; ketone bodies during starvation
Tissue stores of glucose
- glycogen from muscle and liver
- fat from adipose tissue
- cellular mass (protein stores)
Gluconeogenesis
conversion of non-carbohydrate sources into glucose (from glycerol and amino acids)
Homeostasis
state of equilibrium of the internal environment of the body
Cellular oxidation: enzymes
proteins, organic catalysts that control reaction
Cellular oxidation: coenzyme
enzyme activators; includes some vitamins
pantothenic acid (B5), thiamin (B1), riboflavin (B2), niacin (B3) are needed for energy production
Cellular oxidation: substrate
substance upon which an enzyme works
Cellular oxidation: cofactor
assists enzymes; minerals
Cellular oxidation: hormones
secretions from endocrine glands
1. chemical messengers that trigger enzymes
2. thyroxine- regulates metabolism and rate of oxidation
-influences physical and mental growth
-stimulates liver glycogenolysis, gluconeogenesis-raises blood glucose
Cellular oxidation: energy reactions
- anabolism: synthesis of a more complex substance
- catabolism: breakdown; uses and releases energy; creates a constant energy deficit, which must be supplied by food
Total Energy Expenditure (TEE)
BEE + EEPA + TEF
basal energy expenditure + energy expended in physical activity + thermic effect of food
Basal Energy Expenditure (BEE)
minimum amount of energy needed at rest in fasting (amount needed to carry out involuntary work of the body, activity of internal organs, internal temperature)
-affected by extremes in environmental temperature (tropical climate 5-20% increase)
-caffeine, alcohol, nicotine stimulate metabolic rate 7-15%
Energy Expended in Physical Activity (EEPA)
highly variable; activity thermogenesis
Thermic Effect of Food (TEF)
diet-induced thermogenesis (DIT), or calorigenic effect of food (about 10% of total energy expenditure)
-energy needed to digest, absorb and assimilate nutrients
-greater after consumption of CHO and PRO than fat
Basal Metabolic Rate (BMR)
measured in the morning when reclining, awake, relaxed, at normal body temperature, at least 12 hours after last meal, and several hours after strenuous activity
-measures oxygen consumed and carbon dioxide produced
-higher during periods of growth, pregnancy, lactation, fever (7% increase for each degree rise in temperature), some diseases which increase cell activity
-increased by exercise
BMR is affected primarily by:
- sex-women 5-10% lower than men
- age- highest BMR 0-2 years old
-older adults have less activity, less lean body mass, more body fat resulting in lower BMR - body composition, body surface area
- endocrine glands-thyroid
BMR is measured by PBI (protein bound iodine)
measures activity of thyroid gland
1. hormones: thyroxine (T4), triiodothyronine (T3)
2. when PBI is elevated, BMR is elevated
3. measures energy metabolism; measures level of thyroxine produced
4. not a nutritional assessment parameter
Resting Metabolic Rate (RMR)
energy expenditure measured under similar conditions, after a short rest and controlled intake of caffeine, alcohol
more frequently measured than the BMR; greater than BMR (10-20%)
Mifflin St Jeor-use with normal weight and obese individuals
Measures of energy utilization-weight control
following changes in weight is the most practical way of measuring energy balance
Calorimetry
direct- measures heat produced in respiration chamber
indirect- measures oxygen consumed and carbon dioxide excreted using a portable machine, useful with athlete, burns
Respiratory Quotient (RQ)
carbon dioxide expired/oxygen consumed
RQ=1 CHO alone
RQ=0.82 PRO alone
RQ=0.7 fat alone
RQ=0.85 mixed intake
Monosaccharide
glucose, fructose, galactose (simple sugars)
Disaccharides
sucrose (glucose + fructose)
lactose (glucose + galactose)
maltose (glucose +glucose)
Polysaccharide
complex sugars
1. starch-glucose chains; 50% of CHO intake
2. cellulose-resistant to digestive enzyme amylase; adds bulk
3. pectin- non-digestible; thickening quality; fruits
4. glycogen-animal starch; from glucose; stored in muscle and liver
5. dextrin-intermediate product of starch break down
Sorbitol
alcohol from glucose; absorbed more slowly than glucose by passive diffusion; converted to fructose; excess may cause diarrhea
Carbohydrates in order of sweetness
Fructose, invert sugar, sucrose, glucose, sorbitol, mannitol, galactose, maltose, lactose
Carbohydrate sources
flour, cereals, fruits, vegetables, dairy products
Carbohydrate functions
- energy
- protein-sparing action: allows most of protein to be used for tissue synthesis
- regulation of fat metabolism: a CHO restriction leads to ketosis
Composition of protein
carbon, hydrogen, oxygen, nitrogen (16%), sulfur (found in cysteine and methionine)
Amino Acids structure
amino group (NH2)-base
carboxyl group (COOH)-acid
Essential Amino Acids
PVT TIM HaLL
Phenylalanine
Valine
Threonine
Tryptophan
Isoleucine
Methionine
Histidine
Leucine
Lysine
Conditionally essential Amino Acids
during catabolic stress: arginine and glutamine
Tryptophan is a precursor to:
serotonin and nicain
Phenylalanine converts to
tyrosine
Methionine converts to
cysteine
Complete proteins
all essential amino acids in sufficient quantity and ratio to maintain body tissues and promote growth; HBV high biological value
Soy protein, quinoa, and animal protein
Incomplete proteins
deficient in one or more essential amino acids
legumes- low in methionine, cystine, and tryptophan
gelatin- low in methionine, lysine, no tryptophan
Protein classification
- simple-amino acids
- conjugated-simple plus non-protein substance (lipoprotein)
- derived- fragments from simple and conjugated (peptide)
Protein sources
meat, poultry, fish, eggs, milk, legumes
Protein functions
- tissue synthesis, maintains growth, regulates body processes
- inefficient energy source-nitrogen must be removed first (58% of PRO can be converted to glucose)
PRO diet requirements
0.8 g/kg (10-15% of total energy intake)
Fat (lipid) types
- simple: triglycerides (3 fatty acids, 1 glycerol)
- compound: simple fat plus other component (phospholipid -in cell membranes; control passage of compounds in an out of the cell. most are lecithins which contain choline (lipotropic factor). helps prevent fat accumulation in the liver. it functions in the transport and utilization of fatty acids and cholesterol through the enzyme LCAT (lecithin-cholesterol acyltransferase))
- derived: fat substance derived from a simple or compound fat by hydrolysis or enzymatic breakdown; fatty acid, glycerol, steroid
Saturated fatty acids
all available bonds of carbon chain are filled with hydrogen; solid at room temperature
Unsaturated fatty acids
one (mono) or more (poly) double bonds
safflower=most polyunsaturated
canola=most unsaturated
Essential fatty acid
absence will create a specific deficiency disease
linoleic (omega 6)
a-linolenic acid (omega 3)
Linoleic acid (omega 6)
lack creates eczema, poor growth rate, petechiae (red, purple skin spots)
1. if replaces CHO: LDL decreases, HDL increases
2. if replaces saturated fat: total cholesterol decreases, HDL decreases
3. Safflower is the best source
A-linolenic acid (omega 3)
retinal function and brain development; deficiency-neurological changes-numbness, blindness
1. comes mainly from fish oils (EPA, DHA), walnuts, flaxseed, canola
2. decreases hepatic production of triglycerides (inhibits VLDL synthesis); little effect on total cholesterol levels
Structure of fatty acids
- straight hydrocarbon chains terminating in a carboxyl group at one end and a methyl group at the other end
- classified by the number of carbons in the chain, the position of the first double bon, and the number of double bonds
- the location of the first double bound, counted from the METHYL end of the FA, is designated by the omega sign
Hydrogenation
reduction process of adding hydrogen (at the double bond) to unsaturated fatty acids to increase saturation and stability
1. trans-hydrogens across from each other, intake harmful to cell function; found in milk fat, margarines, shortenings, frying fats
2. cis-hydrogens on same side as the double bond; most natural fats and oils
most to least saturated fat
coconut oil, palm kernel, cocoa butter, butter, palm oil, canola
Medium chain triglycerides
SFAs between 6 and 12 carbons-naturally found in milk fat, coconut oil, and palm kernel oil
most to leat monounsaturated fat
olive, canola, peanut, sunflower, coconut (MCT source)
most to least polyunsaturated fat
safflower, corn, soybean, cottonseed, palm kernel
most to least FA in butter and margarine
butter-SAT, MUFA, PUFA
margarine- PUFA, MUFA, SAT
lipid food sources
butter, oils, nuts, bacon
lipid functions
- energy, insulation and padding, depresses gastric secretion so delays emptying
- has less oxygen, more carbon than CHO so provides more energy (more carbons for oxidation)
lipid diet requirements
less than 30% of calories
Alcohol
metabolized as fat-7 kcal/g
kcal=proofoz0.8 (proof = %alcohol*2)
requires no digestion, is readily absorbed by simple diffusion through stomach or small intestine lining and transported unaltered in bloodstream
decreases beta oxidation of fatty acids, promotes triglyceride synthesis
established risk factor for head and neck cancer
may increase risk of developing breast cancer
Winterized oil
salad dressings, won’t crystallize when cold, clear (not cloudy)
corn, soy, cottonseed oils are winterized
Vitamin A: Properties
Fat-soluble, stored in liver; carotene-precursor, provitamin (nutrient changed into vitamin) converted in intestinal mucosal cells
Vitamin A: Function
skin, vision
Vitamin A: sources
yellow, orange fruits (mango); dark green leafy vegetables
cantaloupe, fish, liver, carrots, fortified skim milk, apricots, sweet potato
Vitamin A: needs
M 900mcg RE
F 700 mcg RE
Toxic level 10,000 IU
Vitamin A: deficiencies
Night blindness, nyctalopia, is reversible (detected using dark adaptation test)
Xerophthalmia-corneal damage, not reversible Bitot’s spots on conjunctiva
Dry, scaly skin (hyperkeratosis)
Vitamin D: Properties
Cholesterol is precursor
UV light, fat soluble
7 dehydrocholesterol->D3 cholecalciferol->D2 ergocalciferol
Vitamin D: Function
Ca, P metabolism
Vitamin D: Sources
Sunlight, egg yolk, fortified milk
Vitamin D: needs
AI 5-15 mcg
Vitamin D: deficiencies
Rickets, Osteomalacia
Vitamin E: Properties
Tocopherol, fat soluble
One of least toxic vitamins
High doses of vitamin E may antagonize vitamin K
Vitamin E: Function
Antioxidant, resists hemolysis of RBC
Vitamin E: sources
Vegetable oils (cottonseed), whole grains, green vegetables, almonds
Vitamin E: needs
15 mg; UL 1000 mgs
Vitamin E: deficiencies
Hemolytic anemia
Vitamin K: Properties
Synthesized by bacteria in lower intestinal tract
No toxicity symptoms
Fat-soluble
Vitamin K: Function
Forms prothrombin in liver: aids blood clotting
Given pre-surgery
Calcium metabolism
Vitamin K: Sources
Spinach, kale, broccoli
Green, leafy vegetables
Vitamin K: Needs
M 120 mcg
F 90 mcg
Vitamin K: Deficiencies
Hemorrhage
Affected by: mineral oil antibiotics, anticoagulants
Vitamin B1 (Thiamin): Properties
water-soluble
Lost as temp or pH rises
Heat stable in acids
Vitamin B1 (Thiamin): Function
Oxidation of CHO
More CHO, more need
Metabolism of pyruvate
Vitamin B1 (Thiamin): Sources
Grains, wheat germ, pork, liver
Vitamin B1 (Thiamin): Needs
M 1.2 mg
F 1.1 mg
Vitamin B1 (Thiamin): Deficiencies
Beriberi, muscle weakness, foot drop, memory loss, tachycardia
Lowered erythrocyte transketolase
More plasma pyruvate
Vitamin B2 (Riboflavin): Properties
Lost in UV light
Vitamin B2 (Riboflavin): Function
Energy release from protein
Red cell production
Vitamin B2 (riboflavin): Sources
liver, kidney, meat, milk
Vitamin B2 (Riboflavin): Needs
M 1.3 mg
F 1.1 mg
Vitamin B2 (Riboflavin): Deficiencies
Growth failure
Cheilosis-cracked lips
Angular stomatitis-mouth corner cracks, sore throat
Magenta tongue
Niacin: Properties
Precursor: tryptophan
Essential in all cells for energy production and metabolism
Niacin: Function
Metabolism of CHO, Protein, and fat
Niacin: Sources
Protein, peanuts, RTE cereal, chicken, rice, yeast, milk
Niacin: Needs
M 16 NE
F 14 NE
Niacin: Deficiencies
Pellagra
Dermatitis, diarrhea, dementia
Beefy, bright, red tongue
Symmetrical, pigmented rash in sunlight
Folate: Properties
water-soluble
PABA is a precursor
zinc-dependent
Folate: Functions
DNA synthesis, forms RBC in bone marrow, prevents neural tube defects
Folate: Sources
Fortified dry cereal, liver, kidney, green leafy vegetables, citrus fruits, lentils, beans
Folate: Needs
400 mcg
Folate: Deficiencies
Megaloblastic
Macrocytic anemia
Diarrhea, fatigue
Irritability, dyspnea
Vitamin B6 (Pyridoxine): Properties
INH-isoniazid (B6 antagonist)
Vitamin B6 (Pyridoxine): Functions
Coenzyme in amino acid metabolism: deamination, transamination
More protein-more pyridoxine
Vitamin B6 (Pyridoxine): Sources
Meat, wheat, corn, yeast, pork, liver, RTE cereal
Vitamin B6 (Pyridoxine): Needs
M 1.2-1.7 mg
F 1.3-1.5 mg
Vitamin B6 (Pyridoxine): Deficiencies
Seizures, anemia
Dermatitis, glossitis, peripheral neuropathy
Vitamin B12 (Cyanocobalamin): Properties
Contains cobalt
Bound by intrinsic factor in gastric juice
Vitamin B12 (Cyanocobalamin): Functions
Coenzyme in protein synthesis
Forms RBC
Vitamin B12 (Cyanocobalamin): Sources
Liver, meat, milk, kidney, eggs, fish, cheese
Vitamin B12 (Cyanocobalamin): Needs
2.4 mcg
Vitamin B12 (Cyanocobalamin): Deficiencies
Macrocytic, megaloblastic anemia
Pernicious anemia-after gastrectomy or removal of ileum. Due to lack of intrinsic factor
Vitamin B5 (Pantothenic acid): Functions
Coenzyme A-energy
Synthesis of fatty acids
Vitamin B5 (Pantothenic acid): Sources
Animal foods, grains, legumes
Vitamin B5 (Pantothenic acid): Needs
AI 5 mg
Vitamin B5 (Pantothenic acid): Deficiencies
Rare
Paresthesia in feet
Vitamin C (Ascorbic acid): Properties
Most easily destroyed, structure like glucose
Antioxidant
Needs acid pH
Destroyed by heat, alkaline pH, oxidation
Vitamin C (Ascorbic acid): Functions
Changes proline into hydroxyproline into collagen which strengthens intercellular substances
Wound healing
Aids iron absorption
Vitamin C (Ascorbic acid): Sources
Citrus fruits, potatoes, papaya, dark green, yellow vegetables
Vitamin C (Ascorbic acid): Needs
75-90 mg
Vitamin C (Ascorbic acid): Deficiencies
Scurvy, poor wound healing, bleeding gums, petechiae
Vitamin B7 (Biotin): Properties
Synthesized by intestinal bacteria, inactivated by avidin (protein in raw egg white)
Vitamin B7 (Biotin): Functions
Coenzyme in fatty acid synthesis, converts pyruvate to oxaloacetate in gluconeogenesis
Vitamin B7 (Biotin): Sources
Liver, kidney, egg yolk, yeast
Vitamin B7 (Biotin): Needs
AI 30 mcg
Vitamin B7 (Biotin): Deficiencies
Muscle pain, dermatitis, glossitis
Vitamin B8 (Myo-inositol): Properties
In plants as phytic acid related to sugar contains phosphorous vitamin-like factor
Vitamin B8 (Myo-inositol): Functions
Binds calcium, zinc, iron membrane structure
Vitamin B8 (Myo-inositol): Sources
Outer husks of cereal grains, leafy green vegetables
Calcium: Properties
Most abundant mineral
Regulated by parathyroid hormone, Vitamin D, acid, lactose aid absorption.
Calcitonin lowers serum calcium by inhibiting bone resorption
Calcium: Functions
Blood clotting, cardiac function, nerve transmission, smooth muscle contractility
Calcium: Sources
Dairy products, Leafy vegetables, Legumes
Calcium: Needs
1000-1200 mg
Calcium: Deficiencies
Hypocalcemia leads to tetany
associated with vitamin D and Mg deficiencies
Phosphorous: Properties
Second most abundant mineral
Part of DNA, RNA, and ATP
Phosphorous: Functions
Phospholipids transport fat through lymph and blood
Bone, teeth
Phosphorous: Sources
Meat, milk, poultry, eggs, fish, cheese
Phosphorous: Needs
700 mg
Phosphorous: Deficiencies
Rare
Iron: Properties
Trace mineral
Part of hemoglobin
Food iron: ferric
Absorbable: ferrous
Stored: ferritin
Iron overload: Hemochromatosis treated with iron chelation therapy
Iron: Function
Oxygen transport
Iron: Sources
Heme: animal foods, meat, fish, poultry
Non-heme: cereals, vegetables, poorly absorbed; absorption aided by gastric juice, vitamin C, Calcium helps if oxalates are present.
Does not aid absorption: eggs, tea, milk, cheese
Iron: Needs
M 8 mg
F 18 mg
Iron: Deficiencies
Pale tongue, fatigue
Anemia
Spoon-shaped nails
Pale conjunctivae (mucous membranes lining eyelid)
Higher prevalence in infants and adolescents
Magnesium: Properties
Part of chlorophyll
50% in bone, 50% in cells
Magnesium: Functions
Protein and fatty acid synthesis
Stabilizes structure of ATP
High protein, calcium, vitamin D increases need
Magnesium: Sources
Most foods, milk, bread
Magnesium: Needs
M 420 mg
F 320 mg
Magnesium: Deficiencies
Rare-tremors
Zinc: Properties
Trace mineral
Excess leads to copper or iron deficiency
Zinc: Functions
Increases taste acuity
Enhances insulin action
Stabilizes DNA, RNA
Cell division
Zinc: Sources
Meat, liver, eggs, fish
Phytates and copper decrease absorption
Zinc: Needs
M 11 mg
F 8 mg
Zinc: Deficiencies
Reduced immune function, alopecia, poor wound healing, hypogeusia
Growth retardation and sexual immaturity in adolescents
Iodine: Properties
Trace mineral
Part of thyroxine
Iodine: Sources
Seafoods, iodized salt
Iodine: Needs
150 mcg
Iodine: Deficiencies
Goiter
Fluoride: Properties
Trace mineral
Fluoride: Functions
Teeth, bones
Fluoride: Sources
Soil, water
Fluoride: Needs
M 4 mg
F 3 mg
Fluoride: Deficiencies
Dental caries
Copper: Properties
Trace mineral
Attached to protein ceruloplasmin
Copper: Function
Hemoglobin synthesis
Aids iron absorption
Copper: Sources
Beef liver, kidney, oysters, shellfish, seeds and nuts, dark leafy greens
Copper: Needs
900 mcg
Copper: Deficiencies
Rare: microcytic anemia, neutropenia
Wilson’s disease: low serum copper, genetic absence of liver enzyme
Selenium: Properties
Cooperates with vitamin E
Trace mineral
Selenium: Function
Antioxidant
Tissue respiration
Selenium: Sources
Soil, grains, meat, fish, poultry, dairy
Selenium: Needs
M 55 mcg
F 45 mcg
Selenium: Deficiencies
Myalgia, cardiac myopathy
Manganese: Properties
Trace mineral
Manganese: Functions
Central nervous system
Manganese: Sources
Whole grains, legumes, nuts
Manganese: Needs
1.8-2.3 mg
Chromium: Properties
Absorption enhanced by vitamin C, niacin
Ultra-trace mineral
Chromium: Functions
Aids insulin action
Glucose metabolism
Chromium: Sources
Yeast, oysters, potatoes, liver
Chromium: Needs
25-35 mcg
Chromium: Deficiencies
Insulin resistance
Cobalt: Properties
Exists with B12
Stored in liver
Cobalt: Functions
Maturation of red blood cells
Cobalt: Deficiencies
Related to B12 deficiency
Sulfur: Properties
Part of amino acids
cysteine, methionine
Sulfur: Functions
Components of organic molecules
Sulfur: Sources
Meat, fish, eggs, poultry
Sulfur: Needs
425-550 mg AI
Choline: Properties
Component of lecithin
Choline: Functions
Transports lipids as acetylcholine
Choline: Sources
Fat in eggs, milk, liver, soybeans
Intracellular vs Extracellular Water
ICW- water within cells, ECW-plasma, lymph, interstitial, intercellular
Electrolytes-concentration in milliequivalents
mEq = (mg/atomic weight) * valence
Na: AW=23, Valence=1
K: AW=39, Valence=1
Ca: AW=40, Valence=2
Extracellular Electrolytes
Na, Ca, Cl, HCO3
1. NaCl is 40% sodium
2. 1 tsp=6g NaCl=2.4g Na
3. Na is absorbed by aldosterone and retained by steroids
4. normal saline=0.9% NaCl=154 mEq Na and 154mEq Cl per liter
Intracellular Electrolytes
K, Mg, P
1. Aldosterone increases excretion
2. Hyperkalemia causes cardiac irregularites
Potassium sources
meat, fruits, vegetables (banana, orange, tomato, potato, cantaloupe)
low=apple, cranberry, blueberry, carrot, corn
Osmosis
water moves from less to more concentrated side of membrane
Diffusion
particles move from more to less concentrated side
Effect of protein
exerts colloidal osmotic pressure
Albumin
exerts pressure on blood vessel wall that keeps water within. When albumin drops, the pressure drops, causing fluid to leak out. Water moves to interstitial space. Low serum protein leads to edema and ascites
Anasarca
extreme, generalized edema and widespread swelling of skin due to effusion of fluid into extracellular space
associated with heart, liver, renal failure, and extreme protein/calorie malnutrition
Dehydration
decreased water intake, excessive water output, heavy solute load
1. nausea, dizziness, sunken eyes, fever, hyperventilation, excessive sweating, concentrated urine, dry inelastic skin, increase in solutes (BUN), tachycardia, headache, fatigue, decreased appetite, rapid weight loss
2. Serum sodium is the BEST assessment parameter for fluid status, hypernatremia: dehydration, hyponatremia: over-hydration
Acid-base balance
regulation of hydrogen concentration
acid releases hydrogen ions; base takes up hydrogen ions
buffer- mixture of acid and base components to protect against a strong acid or strong base
Major buffer in body
carbonic acid and sodium bicarbonate
a change in one side of the buffer brings about a compensatory change in the other side to maintain balance; maintain pH close to 7.4
Role of lungs and kidneys: acid-base
- lungs control supply of carbonic acid (carbon dioxide and water)
amount altered by rate and depth of breathing
-hypoventilation-retention of acid; hyperventilation-loss of acid - kidneys control bicarbonate (base)
regulate hydrogen ion secretion and bicarbonate reabsorption
if kidneys retain bicarbonate-level of base increases
if kidney excrete excess bicarbonate-level of base decreases
Respiratory acidosis
Increase in H2CO3
Causes: CO2 retention; hypoventilation; emphysema
Compensatory response: kidneys increase absorption of base (bicarbonate)
Respiratory alkalosis
Decrease H2CO3
Causes: loss of CO2; hyperventilation; anxiety, severe exercise
Compensatory response: kidneys excrete base (bicarbonate)
Metabolic acidosis
Decrease HCO3; Increase H
Causes: kidneys excrete excess base: uremia, diarrhea; increased hydrogen production or retention by kidney; uncontrolled diabetes; starvation; high fat or low CHO diet
Compensatory response: respiration increases to expel CO2; hyperventilation
Metabolic alkalosis
Increased HCO3; decrease H
Causes: abnormal retention of base increased ingestion of alkali diuretics, vomiting; loss of acid diuretics, loss of chloride
Compensatory response: respiration decreases to retain CO2, hypoventilation
Weight gain guidelines during pregnancy
normal weight: 25-35 lbs
underweight: 28-40 lbs
Overweight: 15-25 lbs
Obese: 11-20 lbs
Target at least lower limit
Black and young women: aim for upper end
+1 lb/month 1st trimester
+1 lb/week thereafter
Calories during pregnancy
2nd trimester: +340 kcal
3rd trimester: +452 kcal, 71g PRO
Calories during lactation
1st 6 months: +330 kcal
6-12 months: +400 kcal
71g PRO
At risk during pregnancy
failure to gain 4 lbs/month in last half of pregnancy
< 16 or >/=35 years old
<12 months between pregnancies
pregnant adolescent: needs extra iron , calcium, zinc
Pregnancy supplements
ferrous sulfate: 30mgs during 2nd and 3rd trimester
folic acid: 400 mcg (added to 200 from food)
AI calcium for pregnancy and lactation
</= 18 yrs: 1300 mg
>18 yrs: 1000 mg
Progesterone
hormone that develops placenta after implantation
Linolenic acid in pregnancy and lactation
pregnancy: 1.4 g/day
lactation: 1.3 g/day
Needed for development of fetal nervous system
Avoid during pregnancy:
preformed vitamin A (supplements>5000IU)
shark, swordfish, king mackerel
limit albacore, raw fish
Birthweight categories
Normal birth weight: 2500-4000g
LBW <2500g
VLBW <1500g
ELBW <1000g
SGA vs AGA vs LGA
SGA: <10th percentile BW for GA
AGA: 10th-90th percentile
LGA: >90th percentile
Calorie, PRO, water needs for 0-6 months
108 kcal/kg, 1.52 g PRO/kg, 125-155 mL water/kg, minimum 30 g fat/day
Calorie, PRO, water needs for 7-12 months
98 kcal/kg, 1.2 g PRO/kg, 1.5 mL water/kcal
Neonate
birth to 1 month; can absorb whole, intct protein
Human milk
20 kcal/oz
colostrum: yellowish transparent fluid during first few days; meets infant needs during first week; has more PRO, less fat and CHO; has antibodies
recommend exclusive for first 6 mo; up to at least 12 mo
milk supply is adequate if infant gains weight/length, has frequent stools, and 6-8 wet diapers/day
Maternal hormones-lactation
from pituitary
prolactin stimulates milk production
oxytocin moves milk through the ducts
Human milk composition
PRO: 7%
CHO: 38%
Fat: 55%
Breast fed infant supplement needs
400IU vitamin D from birth
.25 mg fluoride after 6 months if not in water
infant formula
20 kcal/oz; need 2.5 oz/lb/day
has more PRO and iron than HM but lacks antibodies
vitamin D needs met with 1 quart/day
iron-fortified formula recommended for infants on formula
Hyperbilirubinemia
unconjugated bilirubin levels elevated within the first week of life as a result of increased breakdown of RBC or decreased intestinal mobility
Encourage 9-12 feedings per day of human milk or formula to promote hydration and intestinal motility
Fetal iron stores
Decrease at 3-4 months; need additional iron, preferably from formula or supplemental foods (cereal starting at 4-6 months)
One serving of vitamin C rich foods around 6 months to enhance iron absorption from non-heme sources
Introduce solids to infants
4-6 months
sitting posture can be sustained
extrusion reflex diminishes
Begin with iron fortified cereal then strained vegetables or fruits
6-8 months add large finger foods that can be secured with palmar grasp
9-12 months add small finger foods as pincer grasp develops
Cow’s milk for infants
no cow’s milk during 1st year
low and non-fat inappropriate for first 2 years
for those who cannot tolerate cow’s milk-based or soy products use formulas made from casein hydrolysate
Sunken fontanel
dehydration or protein malnutrition
Childhood nutrient needs
- 1-3 growth rate slows (food serving sizes 2-4 oz, 2-4T); 4-6 growth in spurts; 7-10 growth slows
- 2002 RDA PRO: 1-3, 13g; 4-8, 19g; 9-13, 34g
- iron needs: same for boys and girls through age 10
- limit fruit juice to 4 oz/day up to 6 years
- at least 60 min of physical activity each day
- adolescence-final growth spurt; most dietary deficiencies
- 2002 RDA Pro; males 14-18, 52 g; females 14-18, 46 g
- calcium for males and females 9-13: 1300 mg AI
Weight for length (birth-24 mon; young children 2-5)
identifies under/over nutrition
detects short term changes in nutritional status
used to distinguish between stunting and wasting
<5th may reflect acute illness or wasting; >95th over-nutrition
Stature/length for age (birth-24 month recumbent length, 2-20 years height)
defines shortness/tallness
reflects long term nutritional status; determines extent of stunting
affected by long term nutritional stress or chronic illness
<5th short stature
Weight for age (birth-24 month and 2-20 years)
NOT used to classify under/over weight
short term marker of growth; affected by acute nutritional stress or illness
CANNOT distinguish between stunting and wasting because it does not include height
further evaluation needed if below 5th or above 95th percentile
BMI for age percentiles starting at age 2: age and sex specific
Underweight <5th%ile
Normal weight: 5th-84th %ile
Overweight: 85th-94th %ile
Obese >/=95th %ile or >30
Best measure to assess weight in children (includes height, weight, age)
Failure to Thrive in Infants
weight for age falls below 5th %ile on multiple occasions or weight deceleration that crosses 2 major percentiles on a growth chart
may result from acute or chronic illness, restricted diet, poor appetite, lack of fiber leading to chronic constipation, diminished intake
Measurement considerations for infants
measure HC until 3
measure supine length until 2
major reason for large discrepancies in growth patterns is human error in measurement
Newborn initial weight loss
6% loss of birth weight, should be regained by 10-14 days
Weight changes compared to BW (4-5 mo, 1 yr, 2 yr)
4-5 months: BW should double
1 year: BW should triple, length increase by 50%
2 year: BW should quadruple, length should increase by 75%
AAP growth charts to assess children with Down syndrome
no longer reflect population; should not be used
growth charts for other special needs are based on relatively small populations; if used, use along with CDC and WHO growth charts
Lead poisoning
irritability, lethargy, anorexia, vomiting, constipation, anemia
Adulthood nutrient needs
- physical activity determines needs
- RDA PRO; >/=19 males, 56 g; females 46 g
- 45-65% CHO; 20-35% fat; 10-35% PRO
- Fiber: <50, M 38, F 25; >50 M 30, F 21
- Fluid: 35 mL/kg or 1 mL/kcal
Elderly nutrient needs
- young old 65-74; aged 75-84; oldest old 85+
- calorie needs decrease, PRO remains same
- often lack calcium and iron (decreased absorption due to decreased HCl)
- constipation due to decreased gastric motility, decreased HCl secretion in stomach
- fluids: 25-30 mL/kg
- encourage folate-rich foods; supplements of B6 and B12 may be needed
- diet high in antioxidants may delay development of cataracts
- sarcopenia: loss of muscle mass during aging
- more vulnerable to toxicity of vitamin A (increased liver storage, lower blood clearance)
Nutrition and athletics: fluid
athletes need water during physical activity: 16 oz water for every 1 pound body weight lost
during and after continuous endurance physical activity of 1-4 hours, consume fluids that contain CHO and Na
CHO loading, glycogen load
stores 2-3 times normal amount of muscle glycogen
adverse effects: weakness, bloating, dizziness, soreness
Exercise physiology
- at rest and during normal activities, fats are the primary energy source (80-90%); CHO (5-18%); PRO (2-5%)
- during low to moderate intensity aerobic activity (long duration, steady pace) (endurance training), fat is a significant energy source
- exercise above 60-65% of maximal oxygen uptake, CHO is needed as a fuel source
- during prolonged exercise, reliance on CHO to provide PYRUVATE for continued lipid oxidation
- muscle glycogen depleted 2-3 hours of continuous exercise 60-80%
- creatine supplements do NOT enhance endurance (not helpful for marathon runner, soccer player)
Nonnutritive sweeteners
- saccharin (sweet N low), aspartame (NutraSweet, Equal), acesulfame-K (sunette, sweetone), sucralose (splenda), stevia (truvia), neotame
- provide minimal to no energy and must be approved by the FDA
Sugar alcohols: sorbitol, mannitol, xylitol
- 40-100% as sweet as sucrose, resistant to digestion, contribute fewer calories
- can be labeled “sugar-free” but not “calorie-free”
- cavity-preventing (cariostatic) cannot be digested by bacteria responsible for dental caries
- function as humectants (holds water) and emulsifiers, extending shelf life
- more slowly absorbed than other sugars causing diarrhea, abdominal pain, gas (consuming >30g sorbitol not recommended)
Herbals, botanicals, and supplements regulated by the DSHEA: Dietary Supplement Health and Education Act 1994
- clarifies marketing regulations for botanical and reclassifies them as dietary supplements
- plant extracts, enzymes, vitamins, minerals, hormonal products available without prescriptions may carry ‘structure/function’ claims
- the physiological effect can be noted, but no claims about prevention or cure of specific conditions can be made
Black cohash
Primary use: ease menopause symptoms
Potential interaction: may act as blood thinner, effects statins
Comfrey
Primary use: soothe nerves
Potential interactions: irreversible liver disease
Echinacea
Primary use: prevent, moderate cold symptoms
Potential interactions: avoid taking >2 months
Ephedra
Primary use: promote weight loss
Potential interactions: rapid heart rate, headaches; very likely hazardous
Garlic
Primary use: may lower cholesterol, blood pressure
Potential interactions: reduces clotting time; avoid use with warfarin
Ginger
Primary use: antiemetic
Potential interactions: avoid use with drugs that affect bleeding
Ginkgo biloba
Primary use: vasodilation
Potential interactions: avoid use with warfarin, caution with diabetes, avoid pre-surgery
Ginseng
Primary use: immunity, endurance
Potential interactions: high blood pressure, avoid with warfarin; may decrease blood glucose
Kava
Primary use: relieve anxiety
Potential interactions: liver failure, very likely hazardous
Milk thistle
Primary use: may help protect liver
St John’s Wort
Primary use: antidepressive; serotonin-enhancing
Potential interactions: reduces effect of warfarin, avoid with antihypertensives, oral contraceptives, some statins; avoid combinations with spironolactone, thiazide and loop diuretics, hypertensives
Saw palmetto
Primary use: remedy for enlarged prostate
Potential interactions: diuretics
Valerian root
Primary use: calms nerves
Potential interactions: avoid with liver disease
Yohimbe
Primary use: erectile dysfunction
Potential interactions: elevates blood pressure
Digestive Process
- Food in oral cavity is chewed and mixed with saliva secreted by glands in the mouth (parotid, submaxillary, sublingual)
- Food passes into the stomach via the esophagus through the cardiac valve into the fundus, the upper portion of the stomach that holds the bulk of the food to be digested. Most digestion in the stomach occurs in the pyloric (lower) region
- Food is then forced into the small intestine through the pyloric valve of the stomach. Complete digestion and absorption of food takes place in the small intestine (duodenum, jejunum, ileum)
- The hepatic duct from the liever joins with the cystic duct from the gallbladder
- Bile, produced in the liver, is stored in the gallbladder. The liver stores glycogen and synthesizes glucose
- The pancreas lies between the duodenum and the stomach
- Undigested food and water pass through the ileocecal valve into the large intestine or colon
Types of digestion: chemical or enzymatic activity
- in stomach: start of proteolysis by protease pepsin and HCl; limited continuation of starch hydrolysis by salivary amylase
- hormone gastrin stimulates gastric secretions and motility
- hormone CCK cholecystokinin (release from duodenum when fat enters) contracts gallbladder releasing bile, stimulates pancreas
- hormone secretin (duodenum) stimulates flow of pancreatic juice (bicarbonate) and water into the duodenum, inhibits gastric acid secretion
- hormone glucagon-like peptide 1 (GLP-1), hormone glucose-dependent insulinotropic polypeptide (GIP), released from intestine in presence of glucose and fat, stimulates insulin synthesis and release
types of digestion: mechanical or muscular activity
- mastication-produces bolus (mass of masticated food)
- rhythmic contractions of esophagus force food into the stomach where it is mixed with gastric juice and reduced to chyme (acidic)
- Gastric emptying of a meal usually takes between two and six hours. CHO rich and PRO rich foods empty at about the same rate from the stomach. High fat foods and complex CHo, especially soluble fibers, slow gastric emptying
- acidic chyme enters duodenum, mixes with fluids and bicarbonate ions (from pancreas) which neutralize the acid
- most digestion is completed by the middle of the jejunum: nutrients absorbed include amino acids, fatty acids, glycerol, simple sugars, minerals, vitamins
- peristalsis-rhythmic movements of small intestine
types of digestion: bacterial digestion
- large intestine absorbs water, salts, and the vitamins synthesized by bacteria (vitamin K, B12, thiamin, riboflavin) which are used by GI mucosal cells
- colonic salvage: anaerobic fermentaion and absorption of end products of CHO, fiber and amino acid breakdown
- converts malabsorbed CHO and fibers into: SCFA (acetate, butyrate, propionate, lactate) which stimulate water and Na absorption in the colon and provides substrates for energy production; gases (H2, CO2, N, CH4)
Carbohydrate absorption
simple sugars: small intestine-> liver-> converted to glucose or glycogen
Dietary sources of glucose
- 100% CHO
- 58% PRO-glucogenic amino acids (yield glucose following deamination)
-Alanine is the MOST glucogenic amino acid (alanine-glucose cycle) Catabolized to pyruvate or to Kreb’s cycle intermediates - fatty acids and muscle glycogen do not contribute to the body’s supply of glucose
Sources of glucose
dietary
liver glycogen
products oof intermediary CHO metabolism (reconversion of lactic and pyruvic acid)
Uses of glucose
energy
storage
-glycogenesis-in muscle and liver, lipogenesis
small amount is converted into other CHO compounds
-ribose-needed to form RNA, DNA
Hormones control blood glucose level
- insulin-Beta cells of pancreas
-increases cell permeability to glucose; fosters glycogenesis, lipogenesis - glucagon-Alpha cells of pancreas
-induces glycogenolysis (glycogen->glucose) - glucocorticoids
-PRO->glucose (gluconeogenesis)
-requires pyridoxine - epinephrine-adrenal medulla
-stimulates sympathetic nervous system
-stimulates liver and muscle glycogenolysis (glycogen->glucose)
-decreases release of insulin from pancreas during catabolic stress - growth hormone, ACTH (adrenocorticotropic) -insulin antagonists
Energy metabolism
glucose in cell is oxidized to produce energy, carbon diaxide, water (end products of metabolism)
Glycolysis
in cytoplasm
Purpose is to produce pyruvate for the Kreb’s cycle by breaking down glucose, with or without oxygen, into pyruvate or lactate
1. aerobic glycolysis-end product pyruvate
2. anaerobic glycolysis-end product lactate
Steps of glycolysis
- glucose enters cells aided by insulin; combines with phosphorous in presence of magnesium to form glucose-6-phosphate
1a. proceeds to pyruvic acid
1b. may lead to glycogen synthesis
-liver glycogen releases glucose to blood (requires glucose-6-phosphatase-muscles do not have-muscle glycogen must be used in muscles)
1c. proceeds through the pentose shunt (side channeling of glucose)
-does not require ATP; produces ribose and NADPH
2a. pyruvic acid converted to lactic acid, used for muscle contractions when anaerobic
2b. pyruvic acid converted to acetyl COA
-requires thiamin (TDP), niacin (NAD), riboflavin (FAD), pantothenic acid (CoA), magnesium, lipoic acid
TCA, Kreb’s, citric acid cycle
- acetyl CoA (from CHO, fatty acids, or PRO)
- cycle produces 90% of body’s energy as ATP
- CHO is the fuel needed to keep the cycle going
- Oxaloacetate (main CHO fuel) formed from pyruvate and some amino acids reacts with acetyl CoA to form citric acid which starts the cycle
- alpha ketoglutaric acid (from amino acids through gluconeogenesis) needs thiamin for deoxycarboxylation
Full oxidation of 1 molecule of glucose yields:
38 ATP
Protein metabolism
amino acids->intestinal capillaries->portal blood stream->tissues
pyridoxine is needed for the transport of amino acids
Branched chain amino acids
valine, leucine, isoleucine
Exercise and amino acids
exercise releases alanine from muscle proteins; it is transported to the liver deaminated, and converted to glucose
also during exercise, the oxidation of leucine (a BCAA) increases
tyrosine can be synthesized from
phenylalanine
cysteine can be synthesized from
methionine
Nitrogen balance
measures body’s equilibrium
compares intake to output
0 =maintenance, nitrogen equilibrium
+ =net gain in body protein (infant, teenager, pregnancy, healing)
- = erosion of body protein, inadequate intake
formula: PRO/6.25 - UUN (urinary urea nitrogen) - 4
Methods to determine the quality of protein in foods
- BV (biological value)-fraction of absorbed nitrogen retained (egg is BV=100)
- NPU (net protein utilization)=(N intake-N output)/N intake
- Protein Digestibility Corrected Amino Acid Score (PDCAAS)-estimates % PRO actually digested (animal-97%, plant-70-90%)
Protein anabolism (synthesis)
DNA forms RNA on ribosomes; RNA is template for protein carried into cytoplasm
Protein catabolism (pyridoxine is involved)
- deamination-splitting off NH2 by hydrolysis in the liver
- NH2 converted to ammonia which is toxic
- most of NH3 converted to urea and excreted by kidneys
- some NH3 converted to purines, some used to make nonessential amino acids by transamination
- remaining carbon chain is a ketoacid, can be oxidized for energy
Hormonal control of protein use
- pituitary growth hormone, thyroid hormone, insulin, testosterone: anabolism
- adrenal steroids (glucocorticoids)-protein catabolism-stimulate gluconeogenesis
Fat metabolism
- end products of fat digestion: monoglycerides, diglycerides, glycerol, fatty acids
- absorbed directly into portal blood: glycerol (water soluble), short chain fatty acids (<12 carbons), some phospholipids
- monoglycerides, diglycerides, long chained fatty acids combine with bile salts form micelles
-form lipoproteins (chylomicrons); penetrate intestinal mucosa, travel through lymph, into the thoracic duct into the blood - cholesterol: some absorbed with bile salts, most absorbed with cholesterol esterase; converted into cholesterol esters and excreted by the liver as bile
Fat metabolic activities
- lipogenesis (synthesis, deposition), insulin is anabolic hormone
-adipose-most active site: fatty acid+glycerol->triglycerides
—needs NADPH from pentose shunt
-liver-synthesizes fat, but should not store fat
—to prevent fat accumulation: lipotropic factors (choline) produce lipoproteins which transfer fatty acids out of the liver - lipoproteins: chylomicron (diet-derived) largest, mostly triglyceride; VLDL about half TG; LDL smaller, mostly cholesterol; HDL rich in protein
- lipolysis-oxidation forms acetyl CoA which enters Krebs cycle
-growth hormone, glucagon (insulin antagonist)
-glucocorticoids, thyroxine, epinephrine, ACTH-increase rate of fat mobilization
Ketosis
- normal fat metabolism-requires adequate CHO for complete fat oxidation
- abnormal fat metabolism-inadequate CHO (starvation, uncontrolled diabetes) results in incomplete fat oxidation and build up of ketones (which serve as fuel for muscle and brain, but disturbs acid/base balance)
Active transport
mechanism for most nutrients (glucose, amino acids, Na, K, Mg, Ca, Fe)
sodium pump: uphill pumping from lower to higher concentration, across a membrane against energy gradient; requires ATP
Simple diffusion
mechanism for some water and electrolytes
higher to lower concntratio: intestine to blood to lymph
Carrier-facillitated passive diffusion
water soluble nutrients
higher to lower concentration
Factors that aid vitamin and mineral absorption
vitamin A: bile salts, pancreatic lipase, fat
vitamin D: hydroxylated in liver, then kidney; needs bile salts, acidity of chyme; accompanies Ca, P absorption
riboflavin: phosphorous
B12: ileum, stomach secretions (HCl, intrinsic factor)
iron: HCl, calcium interferes (binds oxalates)
folate: zinc dependent, cleaves polyglutamate to monoglutamate (folic acid in fortified foods and supplements is monoglutamate)
Hypothalamus
key brain structure involved in the control of food and energy intake
a. Serotonin: neurotransmitter, low levels increase CHO appetite
b. Leptin produced by fat cells in response to food intake, induces satiety
c. Ghrelin: produced in stomach and intestine, stimulates appetite and growth hormone secretion, decreases fat utilization in adipose
d. low leptin and high ghrelin promote excess food intake
Social Determinants of Health
Conditions in the places where people live, learn, work and play that affect a wide range of health risks and outcomes
Economic stability
Education
Social and community context
Access to healthy foods and safe neighborhoods
Health care