HS251 Exam I

Nutrient Density

Measure of nutrients in a food compared with kcal content; high in nutrients and lower in kcal

Energy density

Measure of kcals in a food compared with the weight of the food

Estimated Average Requirement (EAR)

amount that meets optimal needs of half the individuals in a group; usually broken up by age and gender

Recommended Dietary Allowance (RDA)

Daily amount that meets the needs of nearly all individuals in a group (higher than EAR)

Tolerable Upper Limit (UL)

Maximum daily amount considered safe for a group of similar individuals

Adequate Intake (AI)

Approximate daily amount sufficient to meet needs of individuals in a group; used when insufficient evidence exists

Acceptable Macronutrient Distribution Range (AMDR)

recommended range of intake for macronutrients as % of total daily kcals

Digestion

Breaking down food into individual molecules small enough to be absorbed through the intestinal wall

Chyme

semiliquid, partially digested food mass that leaves the stomach and enters the small intestine

Pyloric sphincter

the gateway for chyme to enter the small intestine from the stomach

Chief cells

synthesize and secrete pepsinogen and gastric lipase

Parietal cells

secrete HCl and intrinsic factor

cecum

the beginning of the large intestine

Colon

largest part of the large intestine; ascending, transverse, descending

Rectum

Final 8-inch portion of the large intestine

Salivary amylase

begins carbohydrate digestion

monosaccharides

one sugar unit

Starch

storage form of glucose in plants

Amylose

straight chains; more resistant to digestion (harder to break down); 40% of starch

Amylopectin

branched chains; 60% of starch, easier to digest

Glycogen

the storage form of glucose in animals

Fiber

the non-digestible food component of plants; most is in the form of cellulose

Glycogenesis

the synthesis of glycogen from glucose

Glycemic index

measures the effects of carbohydrate-containing food or meals on blood glucose levels

Glycemic load

adjusts GI for CHO quantity and cooking/preparation methods

Insulin

hormone that brings glucose levels down

Glucagon

hormone that raises glucose levels

Lipogenesis

the process by which excess glucose is converted to fatty acids

Glycogenolysis

break down of liver glycogen to make glucose

Lipogenesis

conversion of glucose to triglycerides; stored as fat (think liposuction)

Gluconeogenesis

the synthesis of glucose from non-carbohydrate source (stored fat or amino acids)

Carbohydrate Intake Recommendations

RDA: 130g per day; AMDR: 45-65% of daily kcals

Good sources of Carbohydrates

Grains, fruits, starchy vegetables

Insoluble fiber

does not dissolve in water; increases bulk and weight of stool; stimulate peristalsis (speeds up transit time); helps reduce constipation

Soluble fiber

dissolves in water; viscous, form gels that slow gastric emptying, reduced blood cholesterol

Bran

husk, outer protection, provides fiber

Germ

Reproductive material, source of dietary fat, nutrient rich

Endosperm

starch, carbohydrate conveyor of the plant

Probiotics

living organisms (bacteria) associate with health benefits (i.e. fermented dairy, fermented vegetables)

Prebiotics

non-digestable resistant starches (fiber) that support growth & health benefits (i.e. banana, onions, carrots)

Peptide bonds

covalent bond between carboxyl group of one amino acid and amine group of a second

Hydrolysis reaction

addition of water to break a peptide bond

Peptide

amino acid chain with <50 amino acids

Dipeptide

2 joined amino acids

Tripeptide

3 joined amino acids

Polypeptide

10+ amino acids

Denaturation

change in shape of a protein, and thus a change/loss in function ( due to heat, pH or mechanical agitation)

Transamination

a reaction that moves an amino group from one amino acid to an alpha-keto acid to make a new amino acid

Deamination

removal of amine group; produces ammonia and a keto acid

Amino acid pool

Small collections of amino acids from degraded/broken down proteins (limited storage)

Triglycerides

made of three fatty acids, a main type of lipid

Phospholipids

glycerol backbone, 2 fatty acids, phosphate group; has unique water-loving and fat-loving attributes (amphipahtic)

Saturated Fatty Acids

All carbons bound to (saturated with) hydrogen, no double bonds, solid at room temperature

Unsaturated fatty acids

some carbons form a double bond with each other; tend to be liquid at room temperature

Monounsaturated fatty acid (MUFA)

unsaturated fatty acid with one double bond

Polyunsaturated fatty acid (PUFA)

unsaturated fatty acid with two or more double bonds

Free radical

H⁺ ion extracted from site of a double bond forms an unpaired electron (chemically unstable)

Blood glucose homeostasis

70-100 mg/dL fasting

Antioxidants

neutralize free radicals; prevents oxidation of double bonds

Sterols

connecting rings of carbon (and hydrogen)

Omega-3

alpha-linolenic acid (ALA)

Omega-6

linoleic acid

cis fatty acid

unsaturated fat where the hydrogen atoms next to a carbon double bond are on the same side; creates a bent/kinked chain

trans fatty acid

unsaturated fat where the hydrogen atoms next to a carbon double bond are on opposite sides; linear chain

Cholecystokinin (CCK)

hormone that stimulates the gallbladder to release bile

Phospholipase

hydrolyze phospholipids

Micelles

small globular clusters that form spontaneously when certain substances mix with water; in the intestine

Chylomicrons

carry triglycerides; transport triglycerides and cholesterol to peripheral tissues and liver via lymph system; circulate in bloodstream

Lacteal

lymphatic capillaries located in the small intestine that absorb chylomicrons

Lipoprotein lipase (LPL)

remove triglycerides from chylomicrons; occurs in peripheral tissue; made by muscle, heart and adipose tissue; leads to smaller and smaller remnants

Very-low density lipoproteins (VLDL)

produced by the liver from products of chylomicrons; transport triglycerides to muscle and adipose cells

Low-density lipoproteins (LDL)

primary transport of cholesterol; circulate longer, more exposure and binding to arterial walls; more susceptible to oxidation

High-density lipoproteins (HDL))

the “good” lipoprotein; made by the liver; primarily carries cholesterol to liver; high in cholesterol and phospholipids

Macrophages

white blood cells

Foam cells

macrophages and LDLs; stick to artery walls, build up to plaque

Atherosclerosis

a condition where fatty acids and cholesterol build up inside your arteries, forming hard plaque that narrows the blood vessel and restricts the flow of blood

Bioavailability

degree to which a nutrient is absorbed from food and used by the body

Carotenoids

natural yellow and orange pigments found in plants; produce vitamin A

Rickets

inadequate bone mineralization in children; weakened, soft bones (bowed legs); due to lack of Vitamin D

Apolipoprotein B (Apo B)

a main protein found on the surface of harmful fat particles in the blood that can clog arteries; attached to LDL and VLDL