Week Four – October 1 , 2012
Lipids are a large group of molecules that
are not soluble in water and all are non-
LIPIDS WE EAT
- 95% of our dietary lipid; usually
what it means when we say “fat”
- We eat triglycerides and store our
body fat as triglycerides
- Made of 1 glycerol molecule
- Different fatty acids give
triglycerides different properties
Length affects how it is digested and
processed in the body; its function in the
body, and its properties before/when you
eat it; ex. Lauric acid – fat in chocolate that
makes it feel nice in your mouth, medium
Short chain: fewer than 6 carbon atoms
Medium chain: 6-12 carbon
Long chain: 14 or more carbons
Saturated fats (SFA) have no double bonds, while unsaturated fats have 1 or more double bonds (which removes one of
the hydrogen molecules).
Monounsaturated (mufa) = 1 double bond Polyunsaturated (pufa) = 2 or more double bonds
- Affects whether food is a solid or liquid at room temperature (butter is very saturated); how they are processed in
the body (poly, do not stack because of the bonds, so molecules can shift around; liquid at room temp); health.
Saturated Fats: all animal foods, ice cream, butter, tropical oils (coconut oil).
Monounsaturated: olive oil, canola oil.
Polyunsaturated: any vegetable oil, canola, safflower, corn oil, fish, and nuts; omega 3. Where is the double bond?
- The bond closest to the end of the fatty acid
o Omega end
o This bond affects how your body uses the fat.
- Omega 3 fatty acids = double bond at the third carbon
from the end.
- Omega 6 fatty acids = double at the 6 carbon
Cis: hydrogren molecules on the same side as the double
bond, creating a kink; most fats in our diet are in the Cis
Trans: hydrogen molecules on opposite sides; even though it
has double bond, acts as though it doesn’t; trans fats can pack tightly like saturated fats and are hard at room temp; is
written on food labels while cis is not (assumed to be in everthing); found in milk, cheese, and beef; hydrogenated fats:
Crisco, chips, margarine, fries, peanut butter.
Name your fatty acid* they are given common names and numerical notations. Ex. 18:2 -3
Consists of a glycerol backbone with two fatty acids
and a compound that contains phosphate.
A large group of hydrophobic compounds; found in
plant and animals; most common one in animals:
Plant sterols are good for heart health; body absorbs
sterols instead of cholesterol; functional food – helps
Mouth: chewing and lingual lipase
Stomach: churning into small droplets, gastric lipase
Small intestine: bile emulsifies fats into small droplets (micelles); pancreatic lipases break fatty acids off of glycerol; free
fatty acids and Mono glycerides
Lipids are not soluble in water, so digesting them requires the help of
digestive enzymes from pancreas and bile from gall bladder; cells of
intestinal wall secrete hormone (CCK) which causes the gallbladder to
contract and release bile into the duodenum (small intestine); it slows
down the movement while enzymes break the lipids down; micelles
transport the products to the enterocytes of the small intestine.
broken down products, along with free chloestoral are trapped in the
micelle, then they are transp