20,21: lipids

what are fats

lipids solid at room temp

what kind of fatty acids make up fats

saturated fatty acids - no double bonds, pack together well

what are oils

lipids liquid at room temp

what kind of fatty acids make up oils

unsaturated fatty acids - at least one double bond, do not pack well

trans fatty acids are correlated to

CVD risk

what are triglycerides and what are they made of

most common lipid in food and body - glycerol and 3 fatty acids

what are fatty acids

long hydrocarbon chains: 4-24 carbons

what does the number of carbons influence

how much processing is needed and where it goes after absorption

what are sterols

lipids with 4 ring structures instead of long carbon chains

steroid, cholesterol

what are phospholipids

fatty acid attached to phosphate instead of glycerol like triglycerides do

examples of high fat fruits

coconuts, avocados

food sources of long chain saturated FAs

beef, pork lard

food sources of medium chain saturated FAs

milk fat, coconut oil

food sources of monounsaturated FAs

olive oil, peanut oil

food sources of polyunsaturated FAs

sunflower oil, corn oil

food sources of omega3

fish oil, walnuts, flax seed

food sources of omega6

beef, eggs, corn oil

what are trans FAs in

mostly hydrogenated products

where does digestion of lipids occur

small intestine

what does undigested fat do in the small intestine

decrease gastric emptying, increase satiety

what do bile salts and pancreatic lipase do in the small intestine

bile salts emulsify fat

pancreatic lipase breaks down molecules

how are lipids absorbed

enter mucosal cells via passive diffusion → reform triglycerides

how are small and medium chain fatty acids transported

carried via portal vein

how are triglycerides and other lipids transported

slowly carried via lymphatic system by chylomicrons

in what form are lipids taken up by adipose and muscle tissues

free fatty acids

once taken into the liver by chylomicrons, what do free fatty acids and triglycerides do

make all lipoproteins

what is the only lipoprotein that carries exogenous fat

chylomicrons

what lipoprotein carries endogenous fat

VLDL, LDL, HDL

where are triglycerides found in the body

adipose tissue, liver, muscle, blood

what are the 3 parts to utilizing stored FA for energy

mobilization: remove from storage

circulation: transport to active tissues

uptake: taken up by tissues

advantages to fat utilization during exercise

abundant sources in body, more energy dense than carbs and proteins

disadvantages to fat utilization during exercise

many steps involved - oxidize fat much slower than glucose

what is RER

respiratory exchange ratio - % energy coming from fats, carbs, and proteins

how is RER quantified

CO₂ produced to O₂ consumed

fat requires more O₂ than CO₂

do you store more fat or carbs/protein

fat

carbs used for energy, protein used elsewhere

does the proportionality of fat utilized during activity influence long term fat reduction

no - daily activity thermogenesis does

what is he AMDR for lipids

20-35%

how much lipids should we consume (minimum)

no less than 10% energy intake