HLTB11 Term Test 2

photosynthesis

Plants use the sun's energy to convert water and carbon dioxide into sugars

Digestible Indispensable Amino Acid Score

amount of essential amino acids mg/g protein

-chemical composition
-physiological impact
-degree to which they have been processed

classifying carbohydrates

-glucose
-galactose
-fructose

major dietary monosaccharides

condensation

two molecules are joined to form a larger molecule and water is released

hydrolysis

large molecule is broken into 2 smaller molecules by the addition of water

sucrose

fructose + glucose

maltose

glucose + glucose

lactose

glucose + galactose

glycogen

carbohydrate storage in animals (present in liver and muscle)

1g glycogen = 5-10g of water

glycogen:water ratio

raw starch

packed in granules, semi-crystalline structure, resistant to digestion

gelatinization

the process by which starch granules absorb water and swell in size (rapidly digested)

retrogradation

cooling cooked starch, molecules partially re-associate, resistant starch

dietary fibre

polysaccharides and lignin not digested by human enzymes (intact in plant foods)

functional fibre

isolated indigestible carbohydrates shown to have beneficial physiological effects in humans

total fibre

dietary fibre + functional fibre

soluble fibre

dissolves in water or absorbs water to form viscous solutions; readily broken down by colonic microorganisms

insoluble fibre

does not dissolve in water, incompletely fermented in the colon

available carbohydrates

absorbed in small intestines

unavailable carbohydrates

enters the colon

salivary amylase

enzyme that begins carbohydrate digestion in the mouth

-mouth
-stomach
-pancreas
-small intestine

digestion of available carbohydrates

stomach

-inactivated salivary amylase
-no digestion of carbs

pancreas

digests starch to oligosaccharides and maltose

small intestine

oligo- and disaccharides broken into mono- by brush border enzymes

small intestine

monosaccharides absorbed by enterocytes and then enter the bloodstream

lactose intolerance

low levels of intestinal lactase

lactase

needed to digest lactose (sugar found in milk)

large intestine (colon)

breakdown carbohydrates via fermentation to produce gases and short-chain fatty acids

-acetate
-propionate
-butyrate

short chain fatty acids from colonic fermentation

-hydrogen
-carbon dioxide
-methane

gases from colonic fermentation

glycemic index

a method of classifying foods according to their potential for raising blood glucose

glycaemic index

incremental area under the blood glucose response curve elicited by a 50g available carbohydrate portion of a test food expressed as a % of the response after 50g glucose taken by the same subject

GI = 100 x food/glucose

GI formula

-15 g of carbohydrate
-80 calories per serving

starches: values

glycaemic response

effect that a food/meal has on blood glucose levels after consumption

-nature of monosaccharide
-amount (of carbs) consumed
-rate of absorption

glycaemic response elicited by carbohydrates depends on

GL = g x GI/100

glycaemic load formula

refining

processes which change or remove various components of food

-bran layers
-germ
-endosperm

whole/unrefined grains contain:

bran layers

good source of fibres and vitamins

germ

good source of vegetable oils and vit. E

endosperm

contains starch and some protein

refined grains

made largely from endosperm and are mostly starch

cellular respiration or aerobic metabolism

to generate energy, glucose is metabolized via what?

cellular respiration

reactions that break down CLPs in the presence of oxygen to produce CO2, water, and ATP

you can get more energy from carbs per molecule of oxygen

why carbohydrates for intense exercise?

gluconeogenesis

synthesis of glucose from simple, non-carbohydrate molecules (ie. a.a)

regulation of GR: external factors

type and amount of carbs consumed

regulation of GR: internal factors

liver and hormones secreted by the pancreas

insulin

hormone secreted by the pancreas in response to an increase in blood glucose levels

glucagon

hormone secreted by the pancreas in response to an decrease in blood glucose levels

insulin

-increase glucose uptake by muscle and liver
-stimulates storage of glucose as glycogen in liver and muscle

glucagon

-stimulates breakdown of glycogen to glucose
-stimulates gluconeogenesis

hypoglycaemia

low blood glucose

diabetes

high blood glucose

overtreatment of diabetes

type of hypoglycemia that occurs when there is an imbalance between insulin/medication and food/exercise

reactive hypoglycemia

exaggerated insulin response after eating

fasting hypoglycemia

pancreas produces too much insulin, even when someone has not eaten

Type I Diabetes

Insulin deficiency due to destruction of insulin-secreting
cells by the body's own immune system; requires insulin injections/intensive insulin therapy

Type 2 Diabetes

Reduced insulin sensitivity/secretion

gestational diabetes

high blood glucose occurring during pregnancy due to placental hormones which cause insulin resistance

retinopathy

eye damage

nephropathy

kidney failure

neuropathy

nerve damage (pain/numbness)

goal of diabetes treatment

reduce risk of complications

-sugar causes diabetes
-sugar causes tooth decay
-sugar causes heart disease
-sugar causes hyperactivity
-sugar causes obesity

myths about sugar

nutritive sweeteners

contains 4kcal enery/gram

non-nutritive sweeteners

provide little or no energy

-aspartame
-sucralose
-saccharine

artificial sweeteners

-aspartame
-sucralose
-saccharine
-acesulfame

non-nutritive sweeteners

-laxative
-for irritable bowel
-diverticular disease
-lowering cholesterol
-lowering blood glucose

medical uses of fibre

lipids

dietary fat; class of molecules that do not dissolve in water

-triglycerides
-phospholipids
-sterols

3 types of lipids found in food:

-length of their carbon chain
-level of saturation
-shape

fatty acids can differ in:

acetic acid (aka vinegar)

fewer than 6 carbon atoms (short-chain triglyceride)

saturated fatty acids

hydrogen atoms surround every carbon in the chain

monounsaturated fatty acids

lack H atoms at one carbon and have one double bond

polyunsaturated fatty acids

more than 1 double bond

hydrogenation

-addition of hydrogen atoms to unsaturated fatty acids
-creates trans fatty acids

essential fatty acids

cannot be synthesized in the body and must be obtained in the diet: alpha-linolenic (omega 3) acid and linoleic acid (omega 6)

phospholipids

glycerol backbone, 2 fatty acids, phosphate group, and polar head group

phospholipids

-amphipathic (both hydrophilic and -phobic
-are emulsifiers
-forms a lipid bi-layer

emulsifiers

substances that allow fat and water to mix by breaking large fat globules into smaller ones

sterols

lipids containing multiple rings of carbon atoms, manufactured in our bodies

lingual lipase

enzymes in the mouth that digests some triglycerides

lipoproteins

particles which transport lipids and fat-soluble vitamins in the blood

lipaemic

eats very little fat because they can't metabolize or digest it

chylomicron

transport dietary fat to adipose tissue/muscle

VLDL

transport endogenous fat to adipose tissue/muscle

IDL

accept cholesterol from HDL

LDL

carry cholesterol to liver

HDL

pick up cholesterol from tissues

eicosanoids

products of fatty acid metabolism

-blood clotting
-vascular tone
-immune function

eicosanoids regulate:

visible fats

fats we knowingly add to foods

invisible fats

fats hidden in foods; naturally occurring or added during processing

reduced fat foods

had fat removed, had fat replaced, or contain fats that cannot be digested or absorbed

water, ethanol, and sugar

what's in alcoholic beverages?