nutrition chapter 5 - lipids

amdr for fat

20-35% of calorie intake

how many cal in 1 gram of fat

1 g/ 9kal

functions of fat

what type of lipid is the majority of fat in foods

triglycerides

types of lipids

triglycerides

sterols

phono

essential fatty acids

omega 3 (linolenic acid)

omega 6 (linoleic acid)

where does majority of fat digestion occur

small intestine

• some occurs in stomach and mouth

bile

• emulsifier

• contains bile salts

• enhances digestion and absorption

omega 3 fatty acids

• type of triglyceride → polyunsaturated

• linolenic acid

• limited in US diet

• ex:

  • walnuts

  • flaxseed oil

  • salmon

  • chia seeds

omega 6 fatty acids

• triglyceride → polyunsaturated

• linoleic acid

• abundant in US diet

• ex:

  • walnuts

  • soy/corn/sun/safflower oils

  • cashews

  • walnuts

  • chicken oil

benefits of omegas

• parts of cell membrane

• lipids to brain and nerves

• growth

• vision

• skin

• genetic activities

• metabolism

• immune cell functions

• reduces risks of

  • alzheimer’s

  • arthritis

  • cancers

  • dental diseases

  • depression

  • CVD

  • preterm birth

trans fats

• normally semi-solid at room temp (think butter or coconut oil)

• unsaturated fat with at least one trans double bond (instead of cis bond)

• partial hydrogenation

• concern: raises LDL lowers HDL

• natural in things like dairy

• normally not natural and synthetic (margarine, packaged goods)

saturated fat

• each carbon is filled with hydrogen atoms

• maxed out amount of hydrogen

• rigid structure

• alter structure of liver cell membrane

  • increases LDL

• recommended <10% daily intake

• increased intake is associated with CVD

  • but naturally occuring like dairy many not be associated

• food examples:

  • dietary fats that are solid at room temp

  • red meats

  • poultry skin

  • dairy products

  • animal fat

chylomicrons

• specific form of lipoprotein

• cholesterol and reformed triglycerides are coated with protein, phospholipids and cholesterol

• help get the hydrophobic fat into liquids

• triglycerides and cholesterol are broken down into fatty acids and glycerol to use for energy

lipoprotein

water- soluble structure that transports lipids through body

• ex: chylomicrons

lipoprotein lipase (LPL)

enzyme in walls of capillaries

• breaks down the parts of chylomicron

function of fat in the body

• energy storage (infinite capacity compared to protein)

• secrete hormones

• appetite signaling

• shock absorption/ cushioning

• insulation

• cell membranes (phospholipid bilayer)

• transport of other lipids (cholesterol transports triglycerides)

• cell signaling

• hormones (estrogen, testosterone…) and vitamins (vitamin D- sterols)