Nutrition Chapter 5: fats and lipids
HDL
(high density lipoprotein) carries cholesterol from tissues to liver for disposal made in liver good health impact
LDL
(low density lipoprotein) carry cholesterol and other fats to tissues made from VLDL which becomes LDL Bad health impact
VLDL
(very low density lipoprotein) carry triglycerides and other fats from liver to tissues made in liver
lipid digestion
-Mouth: little fat digestion -Bile emulsifiers -Triglycerides breakdown -Short chain fatty acids can go directly into blood stream and into liver -Long chain fatty acids: form lipoproteins goes into lymph and then through blood to liver -Cholesterol in fiber exerted in feces Most fat is absorbed though
Fat intake recommendations
AMDR: 20-35% dietary fat no more than 10% of fat calories from saturated fat NO trans-fat
Hydrogenated oils
adds hydrogens to make it more saturated becomes more solid at room temp (margarine)
Body: energy stores
body's chief form of stored energy
chylomicrons
carry dietary fats from small intestine via lymph and blood to tissues made in small intestine
Food: transport
carry fat-soluble vitamins A, D, E, and K also some phytochemical assist in their absorption
sterols
cholesterol we make it in our body only from animal products produces hormones and bile - an emulsifier
lipoproteins (4)
chylomicrons VLDL LDL HDL
Food: satiety
contribute to feelings of fulness
Food: sensory appeal
contribute to the taste and smell of foods
Functions of fat in the body (7)
energy fuel, energy stores, emergency reserve, padding, insulation, cell membranes, and raw materials
Body: cell membranes
form the major material of cell membranes
Trans-fat
hydrogenated oils -lowers HDL -raises LDL
Body: insulation
insulate against temperature extremes with fat layer under the skin
Omega 6
linoleic food sources: -vegetable oils -nuts and seeds health: -helps blood clot
Omega 3
linolenic food sources: -cold water fish -flax, canola, soy, walnuts (must be converted) health: -lower blood pressure -prevent clots
Body: raw materials
lipids are converted to other compounds: hormones, bile, and vitamin D as needed
Food: texture
makes fried foods crisp and other foods tender
Function of fat in food (7)
nutrients, transport, energy, sensory appeal, appetite, texture, satiety
Phospholipids
one glycerol backbone 2 fat soluble fatty acids 1 water soluble phosphate head make up cell membranes arrange themselves so phosphate heads point out and fatty acid tails point in makes cell membrane capable of letting particular things through
Triglycerides
one glycerol backbone 3 attached fatty acids store and provide energy
Polyunsaturated fats
properties: -more than one point of unsaturation food sources: -fish -some nuts health: -decreases LDL -heart healthy
Monounsaturated fats
properties: -one double bond food sources: -nuts and seeds -avocados -peanut butter health: -decreases LDL -considered heart healthy
Saturated fats
properties: -straight chain fatty acids -solid at room temp food sources: -animal products -coconut oil health: -not as good for you
Body: padding
protect internal organs from shock cushioning with fat pads from inside body cavity
Body: energy fuel
provide 80-90% of resting body's energy much of the energy used for muscular work
Food: energy
provide concentrated energy source
Food: nutrients
provide essential fatty acids, fat-soluble vitamins, and other needed compounds
Body: emergency reserve
serve as emergency fuel supply in times of illness and diminished food intake
Food: appetite
stimulates the appetite
Triglyceride subgroups
triglyceride: saturated and unsaturated unsaturated: monounsaturated and polyunsaturated polyunsaturated: omega-3 fatty acids (linolenic) and omega-6 fatty acids (linoleic)
