Ch 1-2 : Intro to nutrition and dietary guidelines and nutrient recommendations
poop
What are the six classes of nutrients?
- protein
- carbohydrates
- lipids
- water
- vitamins
- minerals
Which ones are energy-yielding?
- proteins
- carbs
- lipids
What is an essential nutrient?
nutrient required for normal body functioning that cannot be made by the body.
- ex. vitamins, minerals.
What are the different categories of the DRIs?
1. Estimated Energy Requirement (EER) - amount of calories an individual needs daily which based on height, gender, age, physical activity
2. Tolerable Upper Intake Levels (UL) - daily amount of nutrient that is likely to be toxic
- since supplements are
Which types of DRI standards can be used as a goal for individual intake?
RDA's = are calculated to meet the needs of nearly all healthy individuals in each gender and life-stage group; based on EAR values
Wht type of DRI standard can be used to evaluate the adequacy of nutrient intake in a population?
EAR's the amount of a nutrient that is estimated to meet the needs of 50% of the people in the population
- EAR's = Estimated Average Requirements
Which DRI standard can help you determine if a supplement contains a toxic level of a nutrient?
UL's represent the maximum level of daily intake of a nutrient that is unlikely to pose a risk; used as a guide for limiting intake when people are planning diets and evaluating the possibility of over-consumption
- UL = Tolerable Upper Intake Levels
Which groups of people are the DRIs intended for?
healthy people
Ch 3: digestion, absorption, and metabolism
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� Where do most digestion and absorption occur?
small intestine
� How does the structure of the intestine aid absorption and what are the necessary anatomical parts of the intestine for absorption?
- mucosa: layer of tissue in the gut wall is responsible for absorbing digestive end products
- circular folds:function to slow down the movement of chyme which allows more time for processing and absorption
- villi: finger like projections cover surface
� What products of digestion are transported by the lymphatic system?
fats, bacteria, and other unwanted substances
� What products of digestion are absorbed and then transported via the hepatic portal circulation?
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� Describe the process of fat digestion and absorption.
- lipase comes from the pancreas (small intestine)
o What components of digestive secretions are critical for fat absorption?
- bile is vital in breaking fat into smaller pieces
- vital to break down macromolecules into smaller fragments
- salivary amylase is vital for the breakdown of starch?carbohydrates
Ch 4: carbohydrates
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� Where does energy production from nutrients occur in our cells?
mitochondria (not sure)
o What pathway produces the most ATP?
Calvin cycle
� Describe what happens during the process of glycolysis.
- glucose into pyruvate which results in 2 ATP
� What are the differences between refined flour and unrefined flour?
- refined Refining is a process by which the fibrous outer bran coating of grains is removed.
--ex. brown rice to white rice
� What is the basic unit of carbohydrate?
sugars aka monosaccharides
o How are bonds between monosaccharides formed? Broken?
- they are linked together by glycosidic linkages which is a covalent bond formed between two monosaccharides by a dehydration reaction
� What are the different fibers and how do we classify them? How do they affect our cardiovascular health and gastrointestinal health?
- lowers our blood cholesterol
� What is the main function of glucose in the body?
glucose acts as an energy source, a fuel which powers cellular machinery
� When blood sugar drops, how do we increase it to maintain normal levels?
- what processes are important
- Describe gluconeogenesis and glycogenolysis (glycogen breakdown)
-ketogenesis: liver makes ketones to spare protein and glucose
* used for energy by brain
-gluconeogenesis: liver makes glucose from amino acids
� What is glycogen and where is it stored?
- storage form of glucose that is stored in adipose tissues, liver, and glial cells in the brain
o Under what dietary conditions do we increase our glycogen stores?
- to increase our glycogen stores, we consume a great amount of carbohydrates
o Under what dietary conditions are our glycogen stores depleted/used?
- our glycogen stores are used when we exercise a lot
* after all carbs is used up, fat is then used for energy but it uses up more oygen
� Compare the roles of insulin and glucagon in regulating blood glucose.
- Where are they made and where do they exert their metabolic actions?
- insulin: lowers blood sugar
- Glucagon: increases blood sugar
- both made in pancreas, and exert their metabolic actions in the liver
� What is diabetes and what symptom is it best characterized/diagnosed by?
- a disease in which the body's ability to produce or respond to the hormone insulin is impaired, resulting in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood and urine.
Ch 5: lipids
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� What is the predominant lipid in our body and food?
- triglycerides
� List two foods that are sources of monounsaturated fatty acids, two that are sources of omega-3 fatty acids, and two that that are sources of cholesterol.
- monounsaturated fatty acids: olive oil and avacado
- omega 3 fatty acids: canned tuna and flax seed
- cholesterol: eggs and meat
� What distinguishes a saturated fat from a monounsaturated fat? From a polyunsaturated fat? From a trans fat?
- saturated fat: solid at room temp and have no double bonds between carbon molecules
* saturated with hydrogens
- monounsaturated fat: oils are liquid at room temp, but solidify at refrigerator temp...can reduce risk of heart disease
- have a single carb
� What is the function of bile in fat digestion and absorption?
bile breaks down fat into smaller pieces
� How are fat-soluble nutrients absorbed and transported throughout the body?
- the fat-soluble vitamins enter the lymph vessels before making their way into the bloodstream.
- Many fat-soluble vitamins travel through the body only under escort by proteins that act as carriers.
o Where do chylomicrons come from and what is their function?
What about VLDL, HDL, and LDL?
-chylomicrons: They transport dietary lipids from the intestines to other locations in the body.
- found in blood and lymphatic fluid
- HDL transports cholesterol removed from body cells back to liver
- LDL delivers cholesterol to body cells or removed by
� How is fat broken down for energy in our body?
- What metabolic processes are involved?
-body breaks down fats into glycerol and fatty acids in the process of lipolysis.
-The fatty acids can then be broken down directly to get energy, or can be used to make glucose
- process is lipolysis
� During fasting/feasting conditions, what happens to fat in our body?
- Is it stored or broken down for energy? What enzymes are important for this?
- during fasting, fat is broken down for energy
- results in weight loss
- during feasting, energy is stored as triglycerides in adipose tissue
� What is the difference between cholesterol and plant sterols? Where are they found in foods? How do they affect our blood cholesterol?
-Plant sterols are found in plant membranes and they lower blood cholesterol by competing with cholesterol for absorption
� How do HDLs differ from LDLs?
- HDL hangs on tightly to the cholesterol it carries and won't let it get loose to attach to arterial walls.
- LDL is referred as very bad for it deposits its cholesterol on the walls of arteries and causes damage
� How are blood levels of LDLs and HDLs related to the risk of cardiovascular disease?
- high levels of LDL cholesterol lead to atherosclerosis increasing the risk of heart attack and ischemic stroke.
- HDL cholesterol reduces the risk of cardiovascular disease as it carries cholesterol away from the blood stream.
� How do the different fatty acids/fats affect our heart disease risk? How do they affect our LDL and HDL levels?
- trans fatty acids raise blood cholesterol levels and risk of heart disease
- unsaturated fats improve cholesterol levels and decrease the risk of heart disease
* mainly comes from nuts and avacados and olive oil
- saturated fats cine from animal product
Ch 6: proteins
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� How does protein quality compare between animal and plant sources?
- animal source: can be high in saturated fat and low in fiber
- good source of protein, B vitamins and minerals
- plant source: good source of B vitamins, fiber, calcium, but in less absorbable forms
� Describe the general structure of a protein. How do they differ from other macronutrients?
held by peptide bonds
- are a chain of amino acids
� What is an essential amino acid?
- cannot be synthesized by the human body in sufficient amounts to meet needs
- must be included in the diet
- if not, new proteins that require them cannot be made unless taken from other body proteins
� What is a limiting amino acid and how does it affect protein synthesis?
- the amino acid in shortest supply during protein synthesis
- also the amino acid in the lowest quantity when evaluating protein quality
� What is protein complementation and when is it important?
- it is the most efficient way to get all 9 amino acids into a a vegetarian's diet
- it is important to combine 2 sources of protein together to ensure you get the 9 essential amino acids
� Explain how the shape of a protein is important for its function. What is protein denaturation and how does temperature and pH affect it?
- protein denaturation involves the the disruption and possible destruction of both the secondary and tertiary structures
- high temps will melt and denature proteins
- pH affect the chemistry of amino acid residues and can lead to denaturation
� What effect does moderate exercise have on protein needs?
protein ingestion helps recover from exercise and replenishes depleted energy stores
Ch 7: energy balance and weight management
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� Explain how energy balance is related to body weight.
- energy balance is a constant body weight
- when energy consumption equals energy expenditure, weight remains constant
- if less energy is consumed than expended, we will lose weight
- if more energy is consumed than expended, we will gain weight
� Describe what it means to be in energy balance, negative energy balance, and positive energy balance.
- energy balance is when energy consumption equals energy expenditure
- negative energy balance: less energy is consumed than expended, so you lose weight
- positive energy balance: more energy is consumed than expended, so you gain weight
o What happens to excess calories when we eat more energy than we expend?
- if you eat more than you burn in a day, your body stores the excess calories to use later when calories are scarce.
o How can dietary carbohydrate and protein be stored as fat? Is this preferred to storing dietary fat?
- dietary proteins are broken down to provide energy because there no mechanism for storing them as amino acids or proteins
- fat can be stored in unlimited amounts and dietary is preferentially stored when energy is consumed in excess.
o When we are in a calorie deficit, how do we meet our energy needs and maintain blood glucose?
- glycogen stores can provide glucose
- glucose is also supplied by the breakdown of protein, which yields amino acids that synthesize glucose via gluconeogenesis
- energy can also be provided by the breakdown of stored fat
- ketones can be produced as an
� What are the components that make up total energy expenditure?
- activity level
- basal metabolic rate
- thermogenic foods
o What is the thermic effect of food?
- the energy required to digest, absorb, and process nutrients, it is the "sales tax" on the energy we eat.
- it equals about 10% of daily energy intake
o What contributes the most to TEE in a sedentary person?
- basal metabolism contributes the most in a sedentary person
o What component is most variable between individuals?
activity level
� How does the distribution of body fat affect the risks of excess body fat?
- excess subcutaneous fat (fat under skin) = no inc in halth risk
- excess visceral fat (fat around organs in abdomen) = inc. health risk
o Describe the differences between "android" and "gynoid" body shapes.
1. android obesity: storage of fat at abdominal region
- apple like body shape and more prone to heart disease, cancer, and metabolic syndrome
2. Gynoid: presence of fat at hip and thigh regions
- have bigger butts too lol
- they are pear shaped but less
o Describe 3 methods for determining body composition.
1. skinfold thickness: measures the thickness of a fold of your skin with its underlying layer if fat
2. DXA: two x ray energies to determine, fat, bone,, and lean mass
3. BIA: resistance to painless, low energy electrical current
� Explain short-term mechanisms that can drive you to eat a meal and one that makes you stop eating when you have eaten enough at a meal.
- ghrelin (stomach) increases food intake and drives you to eat a meal
- CCK (intestine) decreases and makes you stop eating when you have eaten enough
� Discuss the role of leptin in regulating body weight.
- made by adipose cells that inhibit hunger
Ch 8: water-soluble vitamins
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� Where are water-soluble vitamins found in our diet?
citric fruits, dark green veggies, potatoes, grains, protein foods
o Describe the difference between fortification and enrichment.
- Grain enrichment: nutrients that were lost during food processing have been added back
- Grain fortification: vitamins or minerals have been added to a food that ween't originally in the food.
ex. adding vitamin D to milk
� Describe, in general, how water-soluble vitamins are absorbed, transported, stored, and excreted.
- they depend on energy requiring transport systems or must be bound to specific molecules in the GI tract to be absorbed
- most are bound to blood proteins for transport
- easily excreted from the body in urine
� How do vitamins function as coenzymes?
facilitate metabolism in the body
� What B-vitamins affect homocysteine levels and why is this important?
- homocysteine: high levels increase the risk of cardiovascular disease
- if folate or vitamin B12 is deficint, homocysteine can't be converted to methionine, so levels rise
- if vitamin B6 is deficient, homocysteine can't be converted to cysteine so leve
� How can high folic acid intake affect vitamin B12 deficiency?
- folic acid can provide active folate to prevent deficiency
� Why would someone who has had his stomach removed need to receive injections of vitamin B12 to meet his needs?
- the stomach has acid and pepsin that releases vitamin B12 from food
� Why are vegans at risk for vitamin B12 deficiency?
- because vitamin B12 is solely found in animal foods
� Describe the functions of vitamin C in the body.
- Maintains immune system, production of connective tissue, aids in iron absorption, works as a antioxidant and coenzyme
� What are some of the consequences of untreated hypertension (high blood pressure)?
- stroke, damaged brain's blood vessels, blood clots