Lipids Chapter 6

Three Classes of Lipids

Three Classes of Lipids

Triglycerides, Phospholipids, Sterols

Triglycerides

3 fatty acids attached to a glycerol “backbone”

Triglycerides are __________ of all fats

95-98%

Triglycerides Fats Four Groups

Monounsaturated, Polyunsaturated, Saturated, Trans

Monounsaturated

• has 1 double bond

• most heart healthy

Monounsaturated Food Sources:

Olive oil, canola oil, nuts, peanut butter, avocado

Polyunsaturated

• many double bonds (2 or more)

• 2nd most heart healthy

Polyunsaturated Food Sources:

corn oil, soybean oil, vegetable oils, margarine

Saturated

• no double bond

• least heart healthy

• “full of hydrogens”

• carbon hydrogen chain

Saturated Food Sources:

grease lard, bacon, shortening butter, coconut oil, palm oil, beef, pork, chicken

Trans Fats

Artificial

• starts out as a polyunsaturated vegetable oil

• goes through hydrogeneration

Hydrogenation

adding back hydrogens

• adds hydrogen atoms to liquid vegetable oils

During trans fat, ___________ happens

hydrogenation

Cis

natural

Phospholipids

• 1 fatty acid is replaced by a compound containing phosphorus and nitrogen groups

• are in all of our cell membranes

Emulsifiers

disperses fat molecules in a watery medium

Emulsifiers EX:

lecithin

Emulsifiers are in

phospholipids

Sterols

ring structures

Cholesterol is made in the

liver

Cholesterol precursors

Vitamin D

Bile

Cortisol

Sex hormones

Essential Fatty Acids

Linoleic and linolenic

Linoleic

Omega-6

Linolenic

Omega-3

Omega-6 Food Sources:

vegetable oils

Omega-3 Sources

fish, flaxseed, nuts (walnuts)

Mouth

lingual lipase (under the tongue)

• mostly for infants in breast milk

Stomach

gastric lipase

Small intestine

release of bile

• release of CCK hormone

Colon

cholesterol carried out in feces

Lipoprotein

protein molecule that transports fat (lipids) in the blood (made by liver)

Chylomicrons

digestion product

LDL

bad cholesterol

• increase serum cholesterol

Atherogenic

fatty plaque

HLD

good cholesterol

Serum cholesterol should be

less than 200 mg/dl

LDL should be

less than 100 mg/dl

• increase fiber and monosaccharides

HDL should be

greater than 40-60 mg/dl

• exercise and loss weight

• low fat diet

Triglycerides should be

less than 150 mg/dl

• fish oil supplements

AHA Recommendation: Lower cholesterol in diet to

300 mg

AHA Recommendation: lower total fat AMDR to

20-35%

AHA Recommendation: lower saturated fat to less than

10%

Lipid Functions

• fuel 9 kcal/g

• cell membrane

• hormones

• fat-soluble vitamins

• cushion internal organs

• insulation