Exam 1 Flashcards
Nutrition
A science that studies the interactions between living organisms and food
Nutrients
Chemical substances in foods that provide energy and structure and help to regulate body processes
Dietetics
the science or art of applying the priciples of nutrition to the diet.
SoFAS
Solid fat and added sugars
Essential Nutrients
must be provided in the diet (we can’t make them)
Fortified foods
have nutrients added
Enriched grains
have thiamin, riboflavin, niacin, iron and folic acid added
Dietary supplements
contain one or more of the following: vitamins, minerals, plant derived substances, amino acids, concentrates or extracts
Which nutrients are energy yielding?
Carbs, proteins, fats
Macronutrients
the energy yielding nutrients and water
they are needed in the body in large amounts each day
How many kcal/g in carbs?
4
how many kcal/g in protein?
4
how many kcal/g in fat?
9
how many kcal/g in alcohol?
7
Carbohydrates (overview)
Include sugars and starches
Provide 4 kcal/g
(includes fiber, but fiber provides less energy)
Lipids (overview)
Commonly called “fats” or “oils”
are a concentrated form of energy
contain 9kcal/g
Proteins (overview)
-required for growth, maintanance and repair of the body
-can supply energy
made up of different combinations of AA
Provide 4 kcal/g
Micronutrients
- provide no energy, but are necessary for proper functioning of the body
- include vitamins and minerals
- important for good health
- required in small amounts
- can be found in most fresh food
Water
-is a nutrient
-is a macronutrient
makes up 60% of a human body
Functions of Nutrients
- Providing energy
- forming structures
Metabolism
all reactions that occur in the body
Nutrigenomics
the study of how diet affects genes and how genetic variation can affect the impact of nutrients on health
What drives food choices?
- Availability (geography, transportation, income, storage and prep. equiptment)
- Cultural and personal background (religion, ethnic variances, personal preference, emotions, health concerns)
Nutrient density
a measure of the nutrients a food provides compared to its energy content
-high nutrient density is good
The scientific method
- uses an unbiased approach to examine interaction of food, nutrients and health
- 3 steps: Observation, hypothesis, theory
What makes a good experiment?
- quantifiable data
- appropriate sample size
- proper controls
Identifying reliable nutrition information
- Does the information make sense?
- Whats the source?
- Is it based on good science?
- Has the product stood the test of time?
RDA
Recommended Dietary Allowances
DRI (what does it stand for?)
Dietary reference intakes- have replaced RDAs
What have DRIs been developed for?
Calcium, Phosphorus, magnesium, vitamin D, flouride B vitamins and choline Vitamin C, E, selenium, beta carotene Energy and macronutrients Electrolytes and water
What is the purpose of DRIs?
- planning and assesing the diets of healthy people
- meant to promote good health and reduce the incidence of chronic disease
- not neccessary to consume that much each day, but should average out to that much a week
EAR
Estimated Average Requirement
-used to evaluate the nutrient intakes for populations
-is the average amount of a nutrient for good health.
If everyone i nthe population consumed this amount, only 50% would obtain enough to meet their requirments
AI
Adequate Intakes
-recommend specific amouts of nutrients for individuals
RDAs
Recommended Dietary Allowances
- recommend specific amounts of nutrients for individuals
- About 97% of the population would meet its needs by consuming this amount
ULs
Tolerable Upper Intake Levels
- help with the prevention of nutrient toxicities
- Is well above the needs of everyone
- Represents the highest amount of nutrients that will not cause toxicity symptoms
EERs
Estimated Energy Requirements-used to calculate kcals needed to ensure a stable weight in a healthy individual
AMDRs
Acceptable Macronutrient Distribution Ranges
-expressed as ranges or proportions of nutrients for health intake
What do the DRI’s include?
- 4 types of nutrient intake recommendations (EAR,RDA,AI,UL)
- 2 types of energy intake reccomendations (EER,AMDR)
Dietary guidlines for Americans
- Adequate nutrients within kcal needs
- weight management
- physical activity
- food groups to encourage
- fats
- carbs
- sodium and potassium
- alcohol
- food safety
Dietary Guidelines: Foods to increase
-fruits and vegetables
-have half of your grains be whole grain
-increase low fat dairy
-increase protein, including seafood
-oils rather than solid fats
-
Dietary Guidelines: Foods to Reduce
- reduce saturate fat, trans fat, cholesterol and sodium
- reduce beverages with sugar
Daily value (on food label)
the amount of a nutrient in a food shown as a percentage of the recommendation for a person consuming a 2000kcal diet
Authorized Health Claims
-Based on Significant Scientific Agreement
or
-Based on an authoritative statement
Ways to asses dietary intake
- 24 hour recall
- food diary or intake record
- food frequency questionairre
- Diet history
Food Groups
Fruits
Veggies
Grains
Protein Dairy
USDA: How many Vegetables a day?
2.5 cups
USDA: How mayFruits a day?
2 cups
USDA: How many grains a day?
6oz
USDA: How many dairy products a day?
3 cups
USDA How many Proteins a day?
5.5 oz
USDA Hoe many oils a day?
27 g
Digestion
The process of breaking food down into components small enough to be absorbed by the body
Absorption
process of taking substances into the interior of the body
Gastrointestinal Tract
hollow tube consisting of the mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus
–food inside the GI tract is considered outside the body
Is food in the GI tract considered inside the body?
No. it is considered outside the body
Mucus
The viscous material produced by goblet cells.
It moistens, lubricates and protects the GI tract
Enzymes
protei molecules that speed up chemical rections.
These are not changed during reactions
Mouth
Entry point for food into the digestive tract
Releases saliva
chewing helps break down food- is the first step of digestion
Saliva
Moistens food
Contains salivary amylase-breaks down starch
Contains lysozyme- prevents bacterial growth
Salivary amylase
Part of saliva
breaks down starch
Lysozyme
part of saliva
prevents bacteria growth
Pharnyx and Epiglottis
- During swallowing the bolus forces the epiglottis down to cover the passageway to the lungs
- After swalllowing the epiglottis returns to the original position, reopening the airway to the lungs
Esophagus
- Has circular muscles that contract and push the bolus down
- has longitudinal muscles that contract, shortening the passageway ahead of the bolus
- brings food from the mouth to the stomach
Peristalsis
rhythmic contractions that propel food through the GI tract
Gastro-esophageal sphincter
Keeps gastric juices from coming up into the esophagus
When a wave of peristaltic contractions reaches the stomach, it causes the sphincter to relax so the bolus can enter the stomach
Stomach
- Acts a resevoir,
- Releases gastric juice
- Stomach function is regulated by both nerves and hormones
What is in gastric juice?
Water, mucus, HCl, pepsinogen
Is highly acidic
Average person produces around 2L of gastric juice a day
What is the rate of gastric emptying for different foods?
Carbs-fast
Protein-SLower
Fat-slowest
Small Intestine
- Digestion and Absorption
- Large surface area (folds and villi
- Segmentation
- Enzymes
- Hormonal Regulation
Gallbladder
Stores bile, which is produced in the liver
Pancreas
secretes digestive enzymes and bicarbonate ions into the small intestine during digestion
This helps to neutralize the acidity
Basic nutrient absorption of fatty acids
Fatty acids enter the mucosal cell of the small intestines by simple diffusion
Basic nutrient absorption of Fructos
Facillitated diffusion into the mucosal cell of the small intestine
Basic nutrient absorption of Amino Acids
Active transport into the mucosal cell of the small intestine
Large intestine
- Can absorb water and some vitamins and minerals
- has some intestinal microflora
- food moves very slowly through the LI
Intestinal microflora
- are hundreds of types of bacteria
- live on food that has not been absorbed
- can produce nutrients
- produce gas
Probiotics
- Are alive
- Are in the LI
- beneficial bacteria
- hard to tell if supplements work, may help regularity and immune function
- definitely don’t hurt, no evidence if they help
Prebiotics
Are food for the beneficial bacteria in the LI
Work together with probiotics
Celiac Disease
-Gluten triggers an immune response which damages the villi of the small intestine, which results in decreased capability to absorb nutrients
Dry Mouth:Cause
Diseases, medications
Dry Mouth: Consequences
Decreased food intake due to changes in taste, difficulty chewing and swallowing, increased tooth decay and gum disease
Dry Mouth: Treatment/Management
Change medications, use artificial saliva
Dental Pain and loss of teeth: Cause
Tooth decay and gum disease
Dental pain and loss of teeth: Consequences
Reduced food intake due to impaired ability to chew, reduced nutrient absorption due to incomplete digestion
Dental pain and loss of teeth: Treatment/management
Change consistency of foods consumed– possible but less enjoyable
GERD
Heartburn, aka Gasteroesophageal reflux disease
GERD: Causes
Stomach acid leaking into the esophagus due to overeating, anxiety, stress, pregnancy, hiatal hernia or disease processes
GERD: Consequences
Pain and discomfort after eating, ulcers,increased cancer risk
GERD: Treatment/management
Reduce meal size, avoid high fat foods, consume liquids between rather than during meals, remain upright after eating, take stomach antacids and other meications
Diarrhea: Causes
Bacterial and viral infections, medications, food intolerance
Diarrhea: Consequences
Dehydration and electrolye imbalance, difficulty absorbing nutrients (Because food moves too fast through the GI tract)
Diarrhea: Treatment/management
Medications to treat infection, fluid and electrolyte replacement
Constipation: Causes
Low fiber intake, low fluid intake, high fiber in combination with low fluid intake, weak intestinal muscles, not being active
Constipation: Consequences
Discomfort, intestinal blockage, formation of outpouching in the intestinal wall called diverticula
Constipation:Treatment/Management
High fiber/high fluid diet, exercise, medications
Alternate feeding methods
- Enteral or tube feedings
- TPN-total parenteral nutrition
Enteral or tube feedings
- if unable to take in food by mouth (can’t swallow etc), but rest of GI tract runs normally
- tube into the stomach
TPN
Total parenteral nutrition
-if you can’t digest at all, put all nutrients directly into the blood stream
Livers role in transport of nutrients
liver is the gatekeeper between water soluble nutrients absorbed in the small intesting and circulation, they must go through the liver to the bloodstream
Lymphatic systems role in the transport of nutrients
transports larger, fat soluble materials
AMDR for Carbohydrates
45-65% of total calories
endosperm
the largest part of the kernel, it is made up primarily of starch but also contains most of the protein along with some of the vitamins and minerals
bran
the outermost layers, contain most of the fiber and are a good source of many vitamins and minerals
Germ
located at the base of the kernal
Is the embryo where the sprouting occurs.
is a source of oil and is rich in vitamin E
What parts of the grain to whole/unrefined grains contain?
Endosperm, Bran, Germ
What do refined grains contain?
Just the endosperm
They are enriched with thiamin, riboflavin, niacin and iron
They are fortified with folate
-don’t replace the fiber and vitamin E
Monosaccharide
The basic unit of a carbohydrate, a single sugar molecule
What are the 3 most common monosaccharides?
Glucose, galactose, fructose
Where is fructose found?
fruits, vegetables, honey
where is Galactose found?
Milk (as part of lactose)
Disachharides
simple carbohydrates made of two monosaccharides linked together
Which 2 monosaccharides are in sucrose?
Glucose+Fructose
Which monosaccharides are in Maltose?
Glucose + Glucose
Which monosaccharides are i Lactose?
Glucose + Galactose
Oligosaccharides
Short chains of less than ten monosaccharides
-in beans, onions, bananas
Polysaccharides
long chains of monosaccharides, include glycogen found in animals and starch and fiber found in plants
Soluble fiber
- Dissolves in water to form a viscous solution
- Can be broken down by bacteria in the LI, thus producing a small amount of nutrients
Insoluble Fiber
- does not dissolve in water
- can not be broken down by bacteria
Good sources of soluble fiber
legumes, prunes, apricots, raisins, oranges, bananas, oats, apples, eggplane, flaxseed
Good sources of insoluble fiber
Wheat bran, whole-wheat bread, broccoli, corn, eggplant, apple skin, nuts and seeds
Inulin
- Used as supplemental fiber in things like fiber one
- derived from chicory root
- tolerance can vary, some may see gas, bloating, cramps
Summary of digestion and absorption of Carbohydrates
- In Mouth: Salivary Amylase breaks down starch into shorter polysaccharides
- In Stomach: Salivary amylase is inactivated by acid
- In SI: pancreatic amylase completes the breakdown of starch into diasaccharides and oligosaccharides
- At the Villi of SI, enzymes complete the digestion of disaccharides and oligosaccharides into monosaccharides
- . In LI: fiber and other indigestable carbs are partially broken down by bacteria to form short chain fatty acid and gas
Lactose Intolerance
- Normally, lactase is needed to digest lactose If lactose is not digested in the SI it passes through to the LI- which can lead to cramping, and diarrhea.
- Is more common in certain ethnic groups
- Can be diagnosed with a hydrogen breath test
Indigestable Carbs
Resistant starch, fiber and oligosaccharides are not digested in the SI These affect: -transit time -the type of intestinal mocroflora -amount of intestinal gas -nutrient absorption
Carbohydrate function
Provide energy
-The brain and RBC can only use glucose as their energy
in general, how is blood glucose regulated?
Concentration of glucose in the blood is regulated by the liver and by enzymes secreated by the pancreas
Glycemic Response
How quickly and how high blood glucose rises after carbohydrates are consumed
Is altered by :
-the amount of carbs consumed
-the type of carbs consumed
-the amount of protein and fat consumed along with the carbs
Glycemic Index
a ranking of how foods affect the glycemic response
- High is >70,
- Low is <55, this means the blood sugar rises more slowly
Regulating Blood Glucose
- Following a meal, blood glucose levels increase.
- Insulin is released, stimulating the uptake and storage of glucose
- Several hours after a meal, the blood glucose level frops.
- Glucagon is released, stimulating the breakdown of glycogen into glucose and the synthesis of new glucose molecules by gluconeogenesis
Cellular Respiration
-To generate energy, glucose is metabolized through cellular respiration
C6H12O2 +O2 –>6CO2+6H2O+ ATP
What happens when Carbs are limited?
- Gluconeogenesis
- Ketone Formation
Gluconeogenesis
- If the body needs energy, it can break down the muscle
- occurs in the liver and kidney cells
- Some AA can form 3C molecules of pyruvate or oxaloacetate, which can then take part in cellular respiration
Ketone Formation
- oxaloacetate is conserved, so acetly CoA derived from fatty acids will not enter the citric acid cycle
- instead, the liver converts acetyl coA to ketons
- ketones can be used as energy by some tissues (muscle, heart, kidney, brain)
- Sever ketosis increases the blood acidity and can cause death.
Health problems caused by Diabetes (Statistics)
- leading cause of blindness in the US
- accounts for 44% of all new cases of kidney failure
Gestational diabetes
occurs in women during pregnancy
may increase the risk of developing type 2 diabetes later in life
have routine screening
usually is diagnosed around 20 weeks
Type 1 diabetes
Insulin is no longer made in the body
Is an autoimmune disease that comes on rapidly
Is usually diagnosed in adolescents
Type 2 diabetes
Insulin is present but the cells do not respond
Can often be managed with diet and exercise
Risk factors: genetics, obesity, sedentary lifestyle, genetics and environment
Prediabetes
indications that blood glucose levels aren’t maintained as tightly as normal
Immediate symptoms of diabetes
excessive thirst, frequent urination, blurred vision, weight loss (because cells aren’t getting any glucose)
Long term complications of diabetes
damage to the heart, blood vessels, kidneys, eyes and nervous system. Infections are more common, amputations may be neccessary
Diabetes complications due to damage of large blood vessels
- Increased risk of stroke
- high blood pressure and increased risk of heart attack
- blocked arteries in legs
- reduced blood flow to feet
- common infections
Diabetes complications due to damage to small blood vessels
-Bleeding inretina, leading to blindness
-Damage to kidney cells
-nerve damage that causes numbness and pain
-
Diabetes treatment
- Need to maintain tight control over blood sugar
- Diet-may need to eat consistently
- Exercise-increases # of glucose receptors
- oral medication- to increase sensitivity, increase insulin production or decrease liver production of glucose
- Insulin
Hypoglycemia
Symptoms: sweating, rapid HR, confusion, weakness
Treatment:Carbs, can have juice, or take glucose pills
Prevention: balance between insulin and carbs
Carbs and dental caries
Sucrose+Bacteria lead to plaque formation and acid production, which result in the dissolution of tooth enamel and formation of cavities
Rationale behind low carb weight loss diets
- Foods high in carbs stimulate the release of insulin.Insulin promotes energy storage, mainly in the form of fat. So less insulin would mean less fat storage.
- Eating more protein promotes satiety, has slower gastric emptying, so you feel fuller longer.
Carbs and heart disease
diets high in whole grains have been found to reduce the risk of heart disease
water soluble fiber binds dietary cholesterol and reduces absorption
fiber and bowel disorders
diets high in fiber can releive or prevent certain bowel disorders including:
- Hemorrhoids
- Diverticulosis
- Diverticulitis
- Constipation
Diverticulosis
outpouchers in the large intestines
Diverticulitis
inflammation of outpouches (diverticuli) in the large intestine
Colon Cancer and fiber intake
Epidemiological studies have shown that diets high in fiber have lower incidence of colon cancer.
Data from clinical trials do not support this claim
RDA for carbs
130g/day
AMDR for carbs
45-65% total energy
AI for fiber for men
38g/day
AI for fiber for women
25g/day
According to WHO how much of our daily energy should be from added sugars?
Less than 10%
Choosing carbs wisely
- choose whole grains
- limit added sugars-
- increase fruits and vegetables
- monitor portion sizes
On nutrition labels, what does “fiber” mean
it includes both soluble and insoluble fibers
Alternative Sweeteners (general)
Non-nutritive–no kcal
FDA has defined ADI for them based on a body weight of 70kg
Saccharin
- Sweet’n low
- 300x sweeter than sucrose
- developed in 1879
- 1909 USDA said it was “probably safe”
- used during WWI, WWI sugar shortags
- 1970s- studies showed it may cause bladder cancer
- 1979- had to be labeled saying it may be carcinogenic
- 2000 research invalid– doesn’t cause cancer
Aspartame
- Equal
- 200x sweeter than sucrose
- Breaks down when heated
- Can’t be used if someone has PKU–disorder where you can’t process phenylalanine
Acesulfame K
- Sunett/Sweet one
- 200x sweeter than sucrose
- Heat stable
Sucralose
- Splenda
- 600x sweeter than sucrose
Stevia
- Truvia
- 300x sweeter than sucros
- marketed as more natural
- comes from a plant, but is still highly processed and put in higher concentrations than it would ever be found in nature
Sugar alcohols
- contain calories
- are not absorbed as readily as other sugars– provide less energy/contain less calories
- can cause GI symptoms- difficult to digest
Agave
Same amount of energy and carbs as sugar
-lower Glycemic Index, so raises blood sugar more slowly
According to Exchange lists, how many g is one serving of carbs?
15g
USDA Guidelines for Solid Fats
16g
USDA guidelines for added sugars
32g
DASH Diet
Dietary Approaches to Stop Hypertension
rich in fruits, vegetables, whole grains, and low-fat dairy foods; includes meat, fish, poultry, nuts and beans; and is limited in sugar-sweetened foods and beverages, red meat, and added fats
Mediterranean Eating Pattern
Heavy in fruits, vegetables, grains, olive oil, nuts, legumes
Fish/Seafood at least 2 times a week
Moderate in cheese, yogurt, poultry and eggs
Very little meats and sweets
Food label claims: “Free”
Means there is less than 0.5 g per serving
Food label claims: “Low”
Low fat–3g or less per serving
low cholesterol–les than 20mg or cholesterol per serving
Food label claims: Lean/Extra lean
Lean: less than 10g fat, less than 4.5g sat. fat, less than 95mg cholesterol
Extra lean: less than 5g fat, less than 2g sat. fat, less than 95mg of cholesterol
Food label claims: High/ “rich in”
contain 20% or more of the aily Value for a particular nutrient
Food label claims: Good source
contains 10-19% of the daily value for a particular nutrient serving
Food label claims: Reduced
contains 25% less of a nutrient than the regular referene product
Food label claims: Light
contains 1/3 fewer caloirs, or half the fat of a reference food
Food label claims: more
at least 10% of the daily value more than reference food
Food label claims: Healthy
contain no more than 360mg sodium, no more than 60mg of cholesterol, provide at least 10% of A or C or Fe or Ca or protein or fiber
24 hour recall
tells us about food intake information
Nutrition related interview
tells information about diestary supplements, water, meal and snack patterns, alcohol intake ets
Antrhropometric measurements
height, body weight, body composition and body circumference to determine weight-fat distribution
Lab measurements
blood lipid levels, glood glucose levels, measures of protein, vitaminand mineral status
Clinical assesments
Chronic disease risk assesments for heart disease, diabetes, etc
Glycemic Load
Calculated by multiplying a foods glycemic index by the amount of available carbohydreate in a serving of the food
Fasting blood glucose
measured after an 8-12 hour fast and is normally maintained between 70 and 100mg of glucose per 100mL of blood
NHANES
National Health and nutrition examination survey