chapter 4 - carbohydrates Flashcards
what are carbohydrates
energy foods that can rapidly oxidized by body to release energy and heat
primary source of energy
ineepsnive and most abundant
carbs provide energy soruce of _________ calores for pls in US and up to _____ in areas where fats and proteins are scarce
half
80-100%
what are carbohydrates named for
carbon, hydrogen, oxygen
function of carbohydrates
providing energy
1 g = 4 cal
stores half a day supply of carb in liver and muscles as glycogen
providing fiber
what is protein-sparing action
when enough carb (50-100g) then proteins are spaired for primary function of building and repairing body tissues
what happens when there is not enough carb
body will resort to alt method to fuel itself using excess fat
during emergency need for energy fat oxidation is not complete, producing ketones which are acids that accumulate in blood and urine and results in ketosis
how long does ketosis take to occur and what happn
- ketones collect in blood
- 3-4 days of eating <40g = ketosis in mind w sound health wh o arents pregnant
- will feel less hungry
- breath of a person in ketosis has the characteristic smell of nail polish remover.
what is ketoacidosis
level of ketones reach abn high level (usually in diabetic pt from not enough insulin, ill, or dehyrsates)
food sources of carb
plant foods: cereal grains, legumes, veg, fruit, sugar, milk
what are cereal grains
- rice in Latin america, africa, asia, and US
- wheat and corn in bread, cereal, pasta, snack foods in American and European diets
- rue oats in bread and real in US and eurpe
- contains vitamins, minerals, and some proteins
- food producers in US usually enrich (replace lost nutrients through processing) w b vitamins (thiamine, riboflavin, niacin)wh
what is fortification + ex
fortify (add nutrient never part of grain)
ex: folic acid to cereal grains to prevent neural defects
carb in veg
potatoes, beets, peas, starchy beans (lima beans0< corn
green leafy veg = fiber
carb in fruit
fruit sugar, fiber, vitmain, and minerals
carb in fruits
table sugar, syrup, honey, and sugar-rich foods such as desserts and candy
carb in form of sugar wo other nutrients, known as low-nutrient-dense foods
suggestiosn to eat fiber-rich diet
fresh foods ? processed foods
starchy beans and fruits and veg
whole grains (intact ones like brown rice, uionia, barley, cracked wheats, oats)
inc water inktae (6-8 glasses)
fiber from diet ? supplementaldivi
sion of carbs
monosaccharides, disaccharides, polysaccharides
what are monosaccharides
simplest form
sweet, no digestion, directly into bloodstream from small intestine
include glucose, frucstoe and galactose
what is glucose
aka dextrose
carb alll other forms are converted to
found naturally in corn syrup and some fruits and veg
CND, RBC< and brain only use glucose
what is fructose and galactose
fructose - levulose or fruit sugar, found in glucose in many fruits and in honey, sweetest of all monosaccharides
galactose - product of digesting milk, not naturally found
what are disaccharides
- pairs of glucose, fructose, galactose
- must be changed to simple sugars y hydrolysis before absorption
what is sucrose
glucose + fructose
- granulated, powder, brown sugar molasses
- sweetest and least expensive sugars
- sugar cane, sugar beets, sap from maple trees
what is maltose
intermediary product in hydrolysis of starch
produced by enzyme action during digestion of starch in body
created during fermentation that produces alcohol
found in some infant formulas, malt beverage products, and bears
less sweet than glucose or sucrose
what is lactose
sugar found in milk
not found in plants
help body absorb calcium
less sweet than monosaccharides or disaccharides
why is cheese okay for lactose intolerant ppl
in making hard cheese, milk seperates into curd (solid part) and whey (liquid) and lactose goes to whey
what are polysaccharides
complex carbs w many compounds of many monosaccharides
important polysaccharides are search, glcogen, and fiber
what is starch
- found in grains and veg
- storage form of glucose in plants
- veg less starch then grain bc higher mositreu content
- legumes are important source of starch + dietary fiber + proteins
- take longer to digest so supply energy over longer period of timewhe
what are the parts of grain kernels
endosperm - central part, starch is priamrly found here
- tough out covering called bran (used in corase cereals and whole-wheat flour) (fiber)
- germ - smallest part of grain and rice source of b vitamins, vitamin E, minerals, and protein (used in whole wheat)
what are intact grains
all three layers of grain present
what are whole grains
processed enough to imporve taste and digestibityl while having bran and germ partially intact
nutritionally superior to reifoined grains
what are refined grains
bran and germ layer removed , leaving only endosperms
less healthy, rapidly digested, quicker blood sugar responses
what is glycogen
storage form of glucose
hormone glucagon converts glcugoen to glucose
what is dietary fiber
aka roughage
indigestible bc cant be broken down by digestive enzymes
can be insoluble (cant disolve in water) or solubleex of sol
ex of soluble fibers
gums pectins hemicellulouse mucilages
fruit (pectin) : apples peaches plums prunes banans
grains: oats barley legumes dried peas beans lentils
examples of insoluble fibers
cellulose some hemicullulose and lignins
all veg, fruit, whole grains, brown rice, wild rice, wheat brain, nuts, seeds
wwhat is cellulose
priamry source of dietary fibers
found in skin of fruits, leaves and stems of veg and legumes
highly processed foods contain little if any cellulose bc removed during processing
produceses bulk for stool but humans can’t digest cellulose
what is hemicellulose
mainly found in whole-grain cereal
what are lignins
woody part of vegetables such as carrots and asparagus or small seeds strawberries
not carbohydrates
binder in cell walls
why is fiber considered helpful
- lower blood glucose levels in t2d pt
- prevent some colon cancers by moving waste materials through colon faster (reduce colons exposure time to carcinogens)
- prevents constipaition, hemorrhoids, diverticular disease by sotening and increasing size of stool
- Acts like a sponge, absorbing water to soften stools and help prevent constipation
- Some fibers form gels that add bulk to stools which helps relieve diarrhea.
- helps people who are trying to lose weight as fiber swells, the volume helps you feel full + Fiber slows the rate at which the stomach empties
- Fibrous food sources are usually lower in calories than foods that are high in fat.
optimatal rec for fiber vs us diet
rec: 20-35 g/ day
av US: 11g
what percent of americans meet rec fruit and veg intake + what are they
fruit - 13.1%, 2 cups
veg: 8.9% - 2.5 cups
issues w too much fiber
produce discomfort, flatulence, diarrhea, obstruct GI tract if >50 g
insoluble fiber binders (phyti acid or phytate) could prevent absorption of minerals like calcium iron zinc and magnesium
ex of isolated fiber added to manufactured foods
inulin (from chicory root), maltodextrin, methylcellulose
how much fiber in foods labeled high in fiber
at least 5g of fiber per serving
5% or less is low, 20% or more is considered high
what enzymes convert disaccharides to monosaccharides
sucrase, maltase, lactase
digestion of polysaccharides
cellulose wall broken down, starch changed to intermediate product (dextrin) then maltose then glucose
cooking can change starch to dextrin
digestion of starch begins in mouth where enzyme salivary amylase begins change starch to dextrin, then stomach jhuice, final small intestine w digestible carb to change to simple sugars
what happens w amount of glucose reaching cells exceeded amount cells can use
gloucose converted to glycogen which is stored in liver and muscles (glycogen is subsequently broken down only from liver and released as glucose when needed for energy)
if more glucose then body can use or store then converted to fat
insulin
glucose metabolism
secreted by islet of Langerhans in pancreas
maintains normal blood glucose at 70-110 mg/dL
what is hyperglucemia
blood sugar ovever 126 mg.dL
hypoglcyemia
<70 mg/dL
only waste products of carb metblism (oxidation of glucose)
carbon dixodie and water
how much carb per day
roughly 250 g/day
less than 10% from simple sugar (12 tsp)
how much sugar according to AHA
<9 tsp for men and <6 tsp for women
range of min carb per day to prevent ketosis
50-120 g
what to rapidly digest carb (ex: simple refined sugars) result in
swings inblood sugar, insulin resistance, obesity, high bp, t2d, appetite-stimulating and thus cravings
1 cup from the Fruit Group counts as:
- 1 cup raw, frozen, or cooked/canned fruit; or
- 1⁄2 cup dried fruit; or * 1 cup 100% fruit juice
21⁄2 Cups
1 cup from the Vegetable Group counts as:
- 1 cup raw or cooked/canned vegetables; or
- 2 cups leafy salad greens; or * 1 cup 100% vegetable juice
6 ounces 1 ounce from the Grains
Group counts as:
- 1 slice bread; or * 1 ounce ready-to-eat cereal; or * 1⁄2 cup cooked rice, pasta, or cereal
1 cup from the Dairy Group counts as:
- 1 cup dairy milk or yogurt; or * 1 cup lactose-free dairy milk or yogurt; or
- 1 cup fortified soy milk or yogurt; or
- 11⁄2 ounces hard cheese
1 ounce from the Protein
Foods Group counts as:
- 1 ounce seafood, lean meat, or poultry; or
- 1 egg; or * 1 Tbsp. peanut butter; or * 1⁄4 cup cooked beans, peas, or lentils
3 cups
functional fibers
isolated, nondigestible carbohydrates that have been proven to have beneficial effects on human health
extracted from plants or created in laboratory
resistant starch
produced when cereals and grains are processed and baked
total fibers
sum of dietary and functional fibers in a food
functional foods
n food ingredients, such as fiber, are added to foods to provide health ben-efits beyond basic nutrition
various types of fiber
cellulose, gum, beta glucan, psyllium, pectin
glycogen is stored where
Two-thirds of your body’s glycogen is stored in your muscles for use as an energy source during muscular activity.
Your liver stores the remaining one-third of the glycogen for use by the rest of your body
how is high-fructose corn syrup (HFCS) madce
converting about half of the glucose found in cornstarch into fructose.
how much added sugar should someone consume in a day
10% of daily cal
from 2000 cal diet, 200 cal (1 tsp sugar is 16 cal so 12 tsp of sugar)
recommended fiber intake for
- male age 14-50
- female 14-18
- women 19-50
- 38 grams per day for males ages 14 through 50;
- 26 grams per day for 14-to 18-year-old females; and
- 25 grams per day for women ages 19 through 50
glycemic index
measure of the speed at which various carbohydrates are digested into glucose, absorbed, and enter the bloodstream
factors that influence glycemic index
Preparation methods, food combinations, and individual differences in metabolisms
- time of day consumed
- combinations of foods (ex: white bread compared to white bread + peanut butter)
Low glycemic index (GI of 55 or less):
Most fruits and vegetables, beans, legumes, dairy products, and nuts
- Moderate glycemic index (GI 56 to 69):
White and sweet potatoes, corn, brown rice, couscous, rolled oats
- High glycemic index (GI of 70 or higher): Potatoes, rice, white bread, rice cakes, most crackers, bagels, cakes, candy, doughnuts, croissants, waffles, most packaged breakfast cereals
