Science of Nutrition and Food Labeling
1. What are different types of studies conducted? Which is considered the gold standard for proving cause and effect?
a. Case study: individual studies that are based on observation
b. Epidemiological study: population study based on observation
c. Cohort study: epidemiological study that is based on a specific population (ex: 60 year olds in nursing homes in MD)
d. Laboratory study: mechanism based study often using experimental animals
e. clinical/ intervention study: experimental vs. control group. *Determines cause and effect*
2. What information is mandatory to include on food labels?
a. Serving size, servings per container, total calories, and percent daily value of fat, cholesterol, sodium, carbohydrate, vitamin D, potassium, calcium, iron, and daily value for a 2000 calorie diet
3. What is percent daily value? What qualifies poor, good, and excellent sources? a. % daily value indicates how much of a specific nutrient the food source serves based on a 200 calorie diet
i. Below 5%: considered a poor source
ii. 10-19%: considered a good source
iii. Above 20%: considered an excellent source
iv. NOTE*- these percentages apply to nutrients that are beneficial to health
4. List and describe the 3 different health claims that food labels may have. a. Nutrient content claims: defines level off nutrients (low, free, reduced) i. Calorie free: less than or equal to 5 calories per serving*
ii. Low calorie: less than or equal to 40 calories per serving
iii. Reduced calorie: at least 25% lower in calorie than regular
iv. sodium free: less than or equal to 5 mg per serving
v. Low sodium: less than or equal to 140 mg per serving
vi. Fat free: less than 0.5 g of fat per serving * If you want to learn more check out polymer that instructs how proteins are made
vii. Low fat: less than or equal to 3 g of fat per serving
b. Health claims: statement expressing relationship of nutrient and health/ or disease approved by FDA based on scientific evidence
c. Structure/function claims: does not yet have sufficient evidence, or approval by FDA
Food Choices and Human Health:
1. How is hunger managed by the brain? What hormones are involved? a. The hypothalamus is the main control within the brain as it allows the brain and body to communicate by the release and uptake of chemicals. i. Neuropeptide Y: A chemical released from hypothalamus that is a neurotransmitter, that will signal the brain when the body needs If you want to learn more check out income from operations is gross profit less
ii. Ghrelin: hormone from the stomach that is a major signal of hunger. Causes stomach pangs or growling
iii. Leptin: hormone from adipose tissue that suppresses desire to eat 2. What are factors that influence individual food choices?
a. Food seen as a reward, seen as a coping mechanism, appetite (external factors - sight, smell and learned preference), comfort foods, ethnic heritage, weight control Don't forget about the age old question of charles shields utd
b. Individual factors, environment setting, sectors of influence, and social/cultural norms also affect food choices
3. What are the 6 classes of nutrients?
a. Proteins, carbohydrates, lipids, minerals, vitamins, and water 4. How calories per gram are there in carbohydrates, proteins, and lipids? Which is the most concentrated?
a. Protein: 4 kcal/g
b. Carbohydrate: 4 kcal/g
c. Fat: 9 kcal/g *most concentrated calorie source*
5. It is recommended that no more than 35% of your calories come from fat. If your calorie needs at 2200 kcal/day, how many grams of fat should you consume? 6. What is the difference between micro and macro nutrients? Categorize the nutrients as micro or macro.
a. Macronutrients require larger consumption to maintain normal health i. Includes lipids, proteins, and carbohydrates
b. Micronutrients are required in smaller quantities to maintain normal health i. Includes vitamins and minerals
7. Describe phytochemicals If you want to learn more check out rel 180 class notes
a. Beneficial, non-nutrients that are derived from plants
8. What are some of the diet related risk factors that contribute to major chronic diseases (like hypertension or diabetes)?
a. Excess of body weight, high sodium intake, excess alcohol intake, inadequate intake of potassium
9. Define Nutrient Density.
a. Nutrient content divided by kcal content. The amount of nutrients, preferably various nutrients, that a food or meal can supply
a. Amount of heat energy needed to raise the temperature of water by 1 degree celsius (measured by a bomb calorimeter) We also discuss several other topics like econ 200 exam 1
Nutrition Standards and Guidelines
1. In relation to dietary recommendations, what do Americans need to eat less of and what do we need to eat more of? If you want to learn more check out robert johnson texas tech
a. Less: added sugars, saturated fats, and sodium
b. More: fruits, vegetables, dairy, and oil
2. What are the macronutrient requirements?
a. Proteins: 10-35% of kcal
b. Fat: 20-35% of kcal
i. 10% saturated fat
ii. Less than 300 mg of cholesterol
c. Carbohydrates: 45-60% of kcal
3. In Dietary guidelines for Americans, what are the emphasized recommendations?
a. Consume a healthy eating pattern that includes all food and drinks within appropriate calorie level.
i. Healthy eating pattern includes: a variety of vegetables, fruits (whole preferably), grains (half should be whole), fat free/ low fat
dairy, variety of proteins, and oils; limited intake of saturated fats, trans fats, added sugars, and sodium
4. Describe what MyPlate is
a. It is an educational tool based on dietary guidelines to aid consumers in making better food choices. Tells users foods to increase, to balance calories, and foods to reduce
5. On a daily basis, how much fruit, dairy, protein, and vegetables should we consume?
a. Fruit: ~2 cups
b. Protein: 5-6 ounces
c. Vegetables: 2.5-3 cups
d. Dairy: 3 cups
6. What is the difference between a serving and a portion
a. Serving: a unit of measure
b. Portion: amount of food actually served/consumed
7. Define DRI, RDA, EAR, UL, and AI
a. DRI: Dietary Reference Intakes, encompasses RDA, EAR, UL and AI
b. RDA: Recommended Dietary Allowances - the average daily nutrient intake that is sufficient to meet the nutrient requirements for 97-98% of all healthy individuals. Set for most macro and micro nutrients, and is changed with age and gender
i. Usually recommendations are set high to cover variation and most of the population
c. EAR: Estimated Average Requirements - average daily nutrient intake estimated to meet the requirement of half of the healthy individuals i. Requirement to meet minimum amount of nutrient to maintain body’s current physiological state
d. AI: Adequate Intake - recommended average daily intake based on observed experiments by a group of healthy people
i. Used when RDA is not set
e. UL: Tolerable Upper Limit - intake of nutrient that should not be exceeded that may result in adverse health effects
8. Define calorie balance.
a. Eat less, but still enjoy food. Avoiding oversized portions
Nutrition and Physiology:
1. What is the basic unit of life?
a. The cell
2. What is the function of the mitochondria
a. Power plant of cell, supplies ATP
3. What is the function of the ribosomes
a. Protein synthesis
4. What is the function of the cell membrane
a. Controls what enters and exits the cell
5. What is the function of the nucleus
a. Control center of the cell, contains DNA
6. What is the function of the golgi complex
a. Packaging center
7. What is the function of the endoplasmic reticulum
a. Smooth: cholesterol synthesis and fat metabolism
b. Rough: protein production
8. What is the function of the lysosome
a. Housekeeper, gets rid of material
9. What is the function of the membrane receptors
a. Proteins on outer surface of cell and nuclear membrane that detects signals
10.What is the cytoplasm?
a. The fluid between the nucleus and cellular membrane
11.How do nutrients play a role in the skeletal system?
a. Nutrients play a major role in development and maintenance. Aids skeletal system to support and protect
i. Vitamin D deficiency can cause rickets or epiphyseal enlargement in infants
12.How do nutrients play a role in the muscular system?
a. High energy and nutrient requirements, depend on activity. Aids the body to move
13.How do nutrients play a role in the cardiovascular system?
a. Composition of diet can benefit or impair function. Cardiovascular system transports nutrients and oxygen around the body
14.How do nutrients play a role in the endocrine system?
a. Food components affect function of secreting hormones that help control body function
15.How do nutrients play a role in the nervous system?
a. Food components affect function and development to aid in sensation, interpretation, and integration
16.How do nutrients play a role in the lymphatic system?
a. Lipid absorption
17.How do nutrients play a role in the respiratory system?
a. Nutrients can affect the ability to carry oxygen or in protective mechanisms 18.Describe the process of digestion and how carbohydrates, proteins, and fats are absorbed.
a. Digestion begins in the mouth mechanically through chewing and chemically with saliva from 3 pairs of salivary glands (sublingual, parotid, and the submandibular)
i. Saliva moistens food to be chemically sensed as taste and ease swallowing. Contains different enzymes that begin some chemical breakdown:
1. Amylase breaks down starch into polysaccharides
2. Lipase begins fat digestion, breaking down triglycerides into
fatty acids or mono/di glycerides
b. The esophagus continues mechanical digestion as peristalsis pushes food to the stomach
c. In the stomach, HCl and pepsin start to uncoil protein strands as well as activate stomach enzymes. Pepsin is a protein lysing enzyme and will break protein down into its polypeptides
i. Amylase is inactivated by the acidic environment, while lipase still continues to work
ii. Secretory cells in the stomach produce mucus, HCl, and pepsin iii. Muscles of the stomach aid in churning and grinding food into a liquid mass
d. The small intestine allows for breakdown of fats, carbohydrates and proteins as secretions from the pancreas and liver become active here and aid in digestion
i. The pancreas produces amylase that breaks down carbohydrates from polysaccharides into smaller polysaccharides
ii. Intestinal cells secrete different enzymes that further breaks down polysaccharides into monosaccharides and include:
1. Maltase: breaks maltose into 2 glucose monomers
2. Sucrase: breaks sucrose into a fructose and glucose
3. Lactase: breaks down lactose into a glucose and a galactose monomer
iii. Bile produced in liver, goes to the small intestine from the
gallbladder to break fat down into emulsified fats. Emulsified fats broken down by pancreatic lipase into monoglycerides, glycerol, and fatty acids
1. Fatty acids are immediately and easily absorbed
iv. Enzymes from the stomach, pancreas and small intestine split polypeptides into dipeptides, tripeptides, or amino acids
v. Intestinal tri and di peptidase further split peptides into amino acids that can be absorbed
e. The colon reabsorbs water and minerals, and contain microflora that participate in minimal fermentation
f. In the large intestine bacterial enzymes digest some fiber and break it down into fatty acids or gas
g. Finally the rectum and anus store and excrete waste
19.After nutrients are absorbed where do they go?
i. Small fatty acids enter the blood
ii. Larger fatty acids enter the lymphatic system
b. Carbohydrates: glucose, fructose, and galactose enter the bloodstream
c. Proteins: amino acids actively enter bloodstream
20.Where are most nutrients digested and absorbed?
a. The small intestine
21.Describe the structure of the small intestine.
a. The small intestine has many folds that contain villi, which contain microvilli (that produce enzymes) and all together increase the surface area of the small intestine.
b. Between folds, there are glands that secrete mucus
c. Within villi there are
i. Capillaries that carry water soluble nutrients
ii. Lymph vessels that carry lymph material
22.How does fiber function with digestion?
a. Fiber holds water, regulates bowel activity, and binds cholesterol (and some minerals) to be excreted from the body
23.What are the excretory products from feces and urine?
i. Fiber and other undigested material
ii. Sloughed off intestinal cells from microvilli
iii. Microflora (E. coli, etc.)
iv. Bile products
i. Urea from amino acids
ii. Electrolytes - potassium and sodium
iii. Ketone bodies from fat
iv. Bicarbonate and ammonia
1. List the functions of carbohydrates within the body.
a. Main source of energy for most of our cells, adds bulk to food - making us more full, sugars bound to outside of cell membrane aid in cell
communication, and provide fiber that is beneficial to health
2. What is the difference between simple and complex carbohydrates? Give three examples of each.
a. Simple: sugars made of 6 carbon atoms along with oxygen and hydrogen. i. Glucose - body’s predominant fuel
ii. Fructose - fruit sugar
iii. Galactose - one of two components within milk sugar
b. Complex: otherwise known as polysaccharides, long chains of sugar units. Starches and fibers
i. Sucrose: glucose + fructose
ii. Maltose: glucose + glucose
iii. Lactose: glucose + galactose
3. Differ between starch, fiber and glycogen.
a. Glycogen: animal starch composed of long glucose chains, body’s storage form of carbohydrates
b. Starch: from plants
c. Fiber: plant starch composed of long glucose chains resistant to enzymatic degradation (cellulose, hemicellulose)
4. What are the benefits of consuming high fiber foods?
a. Fiber will bind to bile and they will be excreted from the body. Helps to lower cholesterol and lower risk for heart diseases
5. Define lactose intolerance
a. Deficiency in lactase enzyme that causes undigested lactose to become fuel for intestinal bacteria producing gas and irritants that may cause nausea or diarrhea. Affects ~80% of the population.
b. Lactase is present in infants so that they can digest mother’s milk, but during childhood and adolescence that lactase begins to
decrease/disappear in many people
6. How is blood glucose regulated?
a. After a meal, glucose levels rise in blood triggering Beta cells from the pancreas to release Insulin. Insulin causes glycogen formation in the liver and muscles to lower the glucose levels
b. When blood glucose levels drop, alpha cells of the pancreas are stimulated to release glucagon. Glucagon stimulates glycogen conversion to glucose in the liver
7. What is the difference between Type I and Type II diabetes? What are some long term side effects?
a. Type I: often established early in life as an immune response to pancreatic beta cells, eventually stopping the pancreas from making enough (if any) insulin
b. Type II: characterized as insulin resistance, as the insulin in the body does not work to let cells take in glucose. Onset in adulthood.
c. Long Term Risks: blindness, kidney disease, heart disease, nerve damage, increased infections, or possible necessity for amputation of limbs
8. Outline the desirable and diabetic blood glucose values
a. Normal: 100 mg/dL
b. Pre-diabetes: 100-125 mg/dL
c. Diabetes: 125 mg/dL
9. How are carbohydrates digested and absorbed?
a. Some starch broken down into maltose by amylase from salivary glands b. Amylase inactivated by HCl in stomach
c. Pancreatic amylase continues breakdown of starch into maltose d. Enzymes within small intestine break disaccharides (sucrose, maltose, and lactose) into their monosaccharides (glucose, galactose, and fructose) e. Glucose, fructose, and galactose will absorb into bloodstream and be transported to liver
1. What is the function of lipids within the body?
a. Form of condensed energy, insulates and protects the organs. Provides essential fatty acids
2. What are the three main types of lipids?
a. Triglycerides phospholipids, and sterols
3. What is the difference between saturated and unsaturated fatty acids? a. Saturated: carry maximum amount of hydrogen atoms.
i. Mostly solid at room temperature, coming from animal sources b. Unsaturated: do not have maximum amount of hydrogen atoms due to double bonds between some carbons
i. Mostly liquid at room temperature, coming from plant sources
4. What is trans fat?
a. Fatty acids with unusual shapes, arise when polyunsaturated oils are hydrogenated.
i. Increase low density lipoprotein profile
ii. Found in margarines, shortening, and baked goods
5. What are the two essential fatty acids and where can they be found in our diet? a. Linolenic acid: Omega 3 fatty acids
i. Found in fatty fishes (salmon, tuna, herring, etc.), canola oil,
b. Linoleic acid: omega 6 fatty acid, precursor to eicosanoids.
i. Found in grains, fats, and oils
6. What is the function of lipoproteins? What are the three different kinds? a. Function to transport lipids within the body
i. VLDL: very low density lipoprotein
1. Bring triglycerides and cholesterol to the body
ii. LDL: low density lipoprotein
1. Bring triglycerides and cholesterol to the body
iii. HDL: high density lipoprotein
1. Desirable as they search for cholesterol to bring it to the liver 7. What are desirable values of cholesterol, HDLs, and LDLs in our blood? a. Cholesterol: less than 200 mg/dL
b. LDLs: less than 100 mg/dL
c. HDLs: 60 mg/dL and above