nutrition test 2

what are carbohydrates?

major source of energy/ supplies glycogen stores for liver and muscles

monosaccharide

one

disaccharide

two

saccharide

sugar

what are some monosaccharides?

glucose, fructose, galactose

glucose

primary energy source for cells, measured as blood sugars

fructose

sweetest, fruit sugar

galactose

part of milk sugar (lactose)

what are some disaccharides?

sucrose, lactose, maltose

sucrose

table sugar, made from sugar cane or sugar beets

nutritive sweeteners

contribute energy to foods, provide 4 kcal/g

added sugars

nutritive sweeteners added during processing or preparation

what are alternative sweeteners?

substances added to a food to sweeten it but provide no or few calories

what are sugar alcohols?

alternative sweeteners (candies, gums)

nonnutritive sweeteners

intensely-sweet synthetic compounds that sweeten foods without providing kcal

saccharin

most scientific evidence supports its safety

cyclamates

banned in the US since 1970, despite being determined as safe by panel of experts from FDA and NAS

aspartame

brand names include nutrasweet and equal phenylalanine and aspartic acid

stevia

from leaves of south american shrub

polysaccharides

carbohydrates that are made up of more than two monosaccharides

starch

storage form of carbohydrate in plants, mainly in seeds, roots, and tubers

glycogen

storage form of glucose (carbs) in humans, stored/ made primarily in liver and muscles

what’s a whole grain?

the intact, ground, cracked, or flaked seeds of cereal grains, fiber-rich bran, starchy endosperm, oily germ

mouth (carbs)

salivary amylase begins starch digestion

stomach (carbs)

acid inactivates salivary amylase

small intestine (carbs)

main site for carbohydrate digestion/ absorption-site

liver (carbs)

absorbed monosaccharides (glucose, galactose, and fructose) travel to liver

large intestine (carbs)

some soluble fiber fermented/ causes feeling of satiety

rectum (carbs)

little dietary carbohydrate excreted

what happens after eating carbohydrates?

insulin released from pancreas (first organ to respond when blood glucose falls)

glycogenolysis

glycogen breakdown— releasing glucose (not fatty acids) into the blood for fuel- thus raises blood glucose into a normal fasting range

lipolysis

breakdown of triglycerides (fat) for fuel (not for glucose)

ketone bodies

form as a result of incomplete fat breakdown

ketosis

conditions that occurs with very high blood ketone bodies

hypoglycemia

abnormally low blood glucose levels

lipids include (3 classes)

triglycerides, phospholipids, cholesterol

lipids are

insoluble in water, less dense than water

functions of fats

providing and storing energy as fat (adipose), maintaining cell membranes, producing certain hormones

fatty acids contain?

a hydrocarbon chain (carbon and hydrogen atoms) with a methyl group (CH3) at one end and an acid group (COOH)

saturated

each carbon atom in the chain holds 2 hydrogen atoms (no double bonds)

unsaturated

1 or more carbon atoms within the chain lack 2 hydrogen atoms so the molecule has 1 or more double bonds

the 2 essential fatty acids are?

alpha-linolenic acid, linoleic acid

effects of prostaglandins

stimulate uterine contractions, regulate blood pressure, promote immune system response

what are trans fats?

unsaturated fats with at least 1 trans double bond rather than the more common cis double bond

hydrogenation

process that adds hydrogen atoms to liquid vegetable oils

partial hydrogenation

not all double bonds are hydrogenated, natural cis double bonds convert to the unhealthy trans form.

triglycerides

composed of 3 fatty acids attached to a glycerol backbone

phospholipids

a lipid consisting of a glycerol bound to two fatty acids and a phosphate group

lecithin

main phospholipid in foods, such as egg yolks, liver, wheat germ, peanut butter, and soy

hydrophobic region

attracts lipids and avoids water

hydrophilic region

attracts water and avoids lipids

cholesterol

the body uses cholesterol to make various substances, including :bile, vitamin D, steroid hormones

bile

made in liver, stored in gallbladder

stomach (lipids)

minor fat digestion occurs

liver (lipids)

produces bile that helps emulsify fat

pancreas (lipids)

secretes pancreatic lipase enzyme into small intestine

small intestine (lipids)

main site for lipid digestion and absorption

atherosclerosis

disease in which lipid-containing plaques build up inside arteries (main cause CVD)

plaque

forms in an artery when something irritates the lining of the artery wall

arteriosclerosis

hardening of the arteries

hypertension

abnormally high blood pressure levels

lipoproteins

protein molecules which transport lipids in the blood

high- density lipoproteins (HDL)

transports cholesterol away from tissues and to the liver where it can be eliminated

low density lipoprotein (LDL)

conveys cholesterol to tissues, may contribute to atherosclerotic plaque

c-reactive protein

produced primarily by liver in response to inflammation

Omega-3

lowers inflammation/ blood clotting/ blood pressure, fatty fish, canola oil, walnuts, and flaxseed

omega- 6

increases inflammation and blood clotting, animal fats and vegetable oils

what are proteins?

main function is for growth and repair of body cells and tissues

structural proteins

in cartilage, ligaments, bones, hair, skin, and nails

contractile proteins

that enable muscles to move

pigment proteins

such as melanin determine color of eyes, hair, and skin

clotting proteins

that are needed for blood clotting

transport proteins

oxygen and many nutrients are transported in blood by special proteins, lipoproteins, retinol binding protein

antibodies

protecting body against disease

fluid balance

the proper distribution of fluids within bloodstream and body tissues

acid-base balance

maintaining the proper pH of body fluids

amino acids

proteins are made of smaller units

amino group

has nitrogen bonded to 2 hydrogen atoms

R-group (side chain)

varies in each amino acid

acid group

acid portion

essential amino acids

cannot be made by the body, must be supplied by the diet, 9/20 amino acids

nonessential amino acids

can be made by the body, 11/20 amino acids

legumes

plants that produce pods with a single row of seeds, soybeans, peas, peanuts, lentils, and beans

high quality protein (complete protein)

contains all 9 essential amino acids in amounts that support growth, most animal products

low-quality protein (incomplete protein)

lacks or has inadequate amounts of 1 or more essential amino acid. most plant foods and gelatin

whey protein

high quality protein derived from the production of cheese

sickle cell anemia

is an inherited condition that affects red blood cells

stomach (protein)

undergo denaturation by stomach acid and partial digestion by pepsin

small intestine (protein)

further digestion occurs as the pancreas secretes protein-splitting enzymes

liver (protein)

after being absorbed amino acids enter the portal vein and travel to the liver

transamination

transfer of nitrogen-containing group from an unneeded amino acid to a carbon skeleton, forming a non-essential amino acid and a keto acid

deamination

removal of nitrogen-containing group from an unneeded amino acid

nitrogen equilibrium

occurs when healthy adults meet protein & energy needs

gliadin

Protein found in gluten of wheat, buckwheat, barley, and rye

phenylketonuria (PKU)

genetic disorder, caused by lack of enzyme that converts the amino acid phenylalanine to another compound

lactovegetarian

consumes milk and milk products

ovo vegetarian

consumes eggs

lactoovovegetarian

consumes eggs, milk, and milk products