Energy Balance, Nutrition

Question 1

estimated average requirements (EARs) vs recommended dietary allowances (RDAs)

Answer 1

estimated average requirements (EARs): examines likelihood that dietary intake is adequate in a population, most useful in estimating nutritional requirements in populations

recommended dietary allowances (RDAs): examines likelihood that dietary intake is adequate in an individual, used to inform nutrition for individuals

Question 2

contrast the following dietary reference intake (DRI) standards:
a. adequate intake (AI)
b. tolerable upper intake levels (UL)

Answer 2

a. adequate intake (AI): examines likelihood that dietary intake is adequate when no RDA (recommended dietary allowance) is set for a nutrient, used to set nutrition intake goals for individual

b. tolerable upper intake levels (UL): examines likelihood of excess or toxicity, highest level of daily nutrient intake that is likely to be safe

Question 3

the average daily nutrient intake level estimated to meet the requirement of half of the healthy individuals in a particular life stage and gender group

Answer 3

estimated average requirement (EAR)

Question 4

the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97%) healthy individuals in a particular life stage and gender group

Answer 4

recommended daily allowance (RDA)

Question 5

recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group of apparently healthy people that are assumed to be adequate - used when RDA (recommended daily allowance) cannot be determined

Answer 5

adequate intake (AI)

Question 6

highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population

Answer 6

tolerable upper level intake (UL)

Question 7

BMR (basal metabolic rate) vs RMR (resting metabolic rate)

Answer 7

BMR: measured when subject is completely rested - in the morning, after fasting, thermo-neutral environment

RMR: energy required by the body in a resting condition - lying down, post-absorptive stage

Question 8

subcutaneous adipose tissue (SCAT) vs visceral adipose tissue (VAT)

Answer 8

SCAT found just under skin

VAT found around organs, associated with increased health risks

Question 9

hormone which induces satiety and reduces fat storage/increases energy expenditure

Answer 9

leptin

Question 10

what is the function of CCK (cholecystokinin)?

Answer 10

CCK: secreted by duodenal I cells, stimulated by presence of fats and proteins —> increases gut mobility, gallbladder contraction, pancreatic enzyme secretion, gastric emptying/acid secretion

basically induces digestion

Question 11

what is the function of PYY hormone (peptide YY)?

Answer 11

PYY: secreted by L cells of ileum and colon, stimulated by presence of fat —> reduces appetite

Question 12

amylose vs amylopectin

Answer 12

both are starches (polymers of glucose derived from plants)

amylose = linear glucose polymer (alpha1-4 bonds only)

amylopectin = branched glucose polymer (alpha1-4 and 1-6 bonds)

Question 13

why can humans digest starch but not cellulose?

Answer 13

starch contains alpha1-4 and 1-6 bonds, which humans can break down

cellulose (fiber) contains beta-glycosidic bonds that are resistant to digestive enzymes

Question 14

function of soluble vs insoluble fiber

Answer 14

soluble - reduces blood cholesterol via binding to bile acid, delays gastric emptying (promotes satiety), promotes healthy bacteria

insoluble - adds volume to feces to prevent constipation

Question 15

Kwashiorkor vs Marasmus

Answer 15

both forms of PEM (protein-energy malnutrition)

Kwashiorkor: protein deficiency (acute), associated with carb-heavy diet —> severe edema (due to hypoalbuminemia), fatty liver, scaly/cracked skin, brittle hair

Marasmus: protein AND energy deficiency (chronic) —> emaciation, loose skin, head appears larger than body

Question 16

Pt is a 1yo presenting with severe edema, enlarged liver, scaly and cracked skin, and brittle hair that has recently become more blond in appearance. According to parent, the patient’s diet mainly consists of corn and rice (carbohydrates). What syndrome is the patient experiencing?

Answer 16

Kwashiorkor: protein deficiency (acute), associated with carb-heavy diet

—> severe edema (due to hypoalbuminemia), fatty liver, scaly/cracked skin, brittle hair (loses color)

Question 17

alpha vs omega fatty acids

Answer 17

alpha FA: terminal carboxylic acid group (-COOH)

omega FA: terminal methyl group (-CH3); important component of cell membranes and building blocks for eicosanoids* (ex: linoleic acid, linolenic acid)

*recall 4 classes of eicosanoids: prostaglandins, prostacyclins, thromboxanes, leukotrienes