Hydrogenation

 Hydrogenation

If an unsaturated vegetable fat is altered by adding hydrogen atoms, which did not exist in nature, the fat molecule is said to be "hydrogenated." 

Hydrogenation transforms the shape of a fatty acid to a "trans" form. 

This molecule does not occur in nature, and the body has difficulty digesting it

This is the problem with margarine — it contains hydrogenated, trans-fatty acids. 

Studies show this type of molecule to be more associated with artery disease than the saturated ("hard") fat found in butter. 

hydrogenated fat also is commonly associated with junk food: potato chips. cookies, etc. 

It is very hard to digest and is strongly associated with vascular disease. 

Trans Fatty Acids

Naturally present in small amounts (<1% of total calories) in animal food sources, including human milk

Mainly introduced in the food chain by the industrial process of hydrogenation

This process is used to make oils solid at room temperature( margarine)

 Triglycerides

A fat molecule is composed of three fatty acid molecules, sixteen to eighteen carbons long, bound to each carbon of the three-carbon-long glycerol molecule. 

It is in the fatty acid chains where saturation, mono unsaturation, poly unsaturation, and hydrogenation occur

Three fatty acids combine with a glycerol molecule to form triglyceride. 

A triglyceride may be solid (fat) or liquid (oil) at room temperature depending on the degree of saturation of fatty acids and length of carbon chain of the fatty acids constituting 

Cholesterol:  It is a fat like lipid that normally occurs in the blood and all cell membranes. It is a major part of brain and nerve tissues. Cholesterol is necessary for normal body function as structural material components of cell membrane in body cells, and in the production of bile acids, vitamin D and sterol/sex hormones.

Some cholesterol is supplied by food, and the body can synthesizes some. 

Average levels of dietary cholesterol are 305mg/day for woman and 440mg/day for men. 

The body synthesizes several time this amount

Heredity, diet, exercise, and other conditions affect   blood cholesterol levels. 

Persons with high blood cholesterol levels appear to be more likely to develop atherosclerosis

RECOMMENDED INTAKE OF FATTY ACIDS

ADULTS: The fat content of the diet should be reduced to 35% of energy, unsaturated fatty acids should be increased and saturated fatty acids should provide only 10% of food energy. Tran’s fatty acids should not contribute more than 2% of total fat intake.

Babies: The linoleic acid content of milk lipids varies in amount (3–12%), depending on maternal dietary intake and possibly smoking habit. α-Linolenic acid makes up 0.4% of human milk. 

Infant formula feeds do not always meet these requirements

Lipoproteins

These are compound lipids that contain both protein and various types and amounts of lipids. 

They are 25-30 % proteins and the remaining as lipids. 

They are made mostly in the liver and are used to transport water insoluble lipids throughout the blood, soluble fat protein complexes

 High-density lipoprotein(HDL): Transports lipids from tissues to the liver and decreases the risk of Chronic degenerative diseases 

Low-density lipoprotein(LDL): Transports lipids from the liver to the tissues  and increases the risk of Chronic degenerative diseases

Consumption of Saturated fats increases LDL level, while= increases risk factor for CHD and other chronic non communicable diseases

Consumption of PUFAs and MUFAs increase the level of HDL = Protective effect form CHD and other chronic non communicable diseases

Desirable Blood Lipid Levels

Total Cholesterol         < 200

Triglycerides            < 150

LDL                        < 100

HDL                > 40 Male

                        > 50 Female

Elevated Blood Lipid Levels (Hyperlipidemia) = increased risk for CHD, Hypertension, Stroke, MI