Along with sterol, phospholipids make up 5% of lipids in diet
Best know phospholipids is lecithin
Has backbone of glycerol
2 of it 3 attachments occupied by fatty acid like those of triglycerides
The third space occupied by a phospholipids group and a molecule of choline
Soluble in both fats and water
Fatty acids make phospholipids soluble in fat
Phosphate group allow phospholipids to dissolve in water and this allows the phospholipids used as an
Emulsifier to mix with water in products such as mayo and candy.
Phospholipids are found naturally in foods
The richest sources of lecithin are in:
ACTION OF PHOSPHOLIPIDS:
Lecithin’s decrease other phospholipids are important composition of cell membranes
Helps lipids move across cell membranes because soluble in both water and fats such as
Act as an emulsifiers keeping fat suspended in the blood and body fluids
Do not need to take supplement of lecithin because the liver makes lecithin from scratch
Large doses of lecithin can cause GI distress, sweating and loss of appetite
Phospholipids, including lecithin, have a unique chemical structure that allows them to be soluble in both water and fat. In the body, phospholipids are part of cell membranes; the food industry uses phospholipids as emulsifiers to mix fats with water. A cell membrane is made of phospholipids assemble into an orderly formation called a bilayer. The fatty acid tails orient themselves away from the watery fluid inside and outside of the cell. The glycerol and phosphate heads are attracted to the watery fluid.
Most common sterol is cholesterol. Cholesterol is made in the body and comes from foods. Derived from both plants and animal contain sterols, animals contain significant amounts of cholesterol.
Cholesterol is in dietary foods and blood. The good and bad cholesterol is found in blood only. The chemical structure of good cholesterol and blood cholesterol have the same chemical structure but cholesterol that is made in the body is called ENDOGENOUS, whereas cholesterol from outside the body (from food) is called EXOGENOUS. Vitamin D, a fat-soluble vitamin, is synthesized from cholesterol.
Sterols other than cholesterol is found in plants, are structurally similar to cholesterol but plant sterols interfere with cholesterol absorption this lowering cholesterol levels. Margarine is a functional food with plant sterols to help reduce blood cholesterol.
ROLES OF STEROLS
Many important body compounds are sterols. Among them are:
Sex hormones, testosterone
Adrenal hormones, cortisol
Cholesterol in the body is the starting material for synthesis of:
Steroid hormones such as testosterone, androgens, estrogens, cortisol, progesterone, cortisone
Sterols have a multiple ring structure that differs from the structure of other lipids. In the body, sterols include cholesterol, bile, vitamin D, and some hormones. Animal derived foods contain cholesterol. To summarize, the members of the lipid family include:
SUMMARY OF LIPIDS:
fats and oils and made up of
* Glycerol: 1 per triglyceride
* Fatty acids: 3 per triglyceride and fatty acids maybe:
* Saturated, no double bonds
* Monounsaturated, 1 double bond
* Polyunsaturated, more than 1 double bond and depending on location of the double bonds polyunsaturated fatty acids maybe: * Omega-3 where 1st double bond is 3 carbons away from methyl group (CH3) * Omega-6 where 1st double bond is 6 carbons away from the methyl end
MAJOR SOURCES OF SATURATED FATS:
* Whole milk, cream, butter, cheese
* Fatty cuts of beef and pork
* Coconut, palm, and palm kernel oils
MAJOR SOURCES OF OF CHOLESTEROL
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