Senin, Februari 19, 2007


Cholesterol belongs to the same chemical family as steroids and is related to fat. It is important for the production of cell membranes, myelin sheaths around nerves, sex hormones, bile, and vitamin D.

Dietary cholesterol is the cholesterol consumed from the diet. Blood Serum cholesterol is the amount of cholesterol circulating in the bloodstream. The two are not closely related. Some people consume large quantities of dietary cholesterol and have a low serum cholesterol level. And, conversely, some people have high blood serum levels and consume very little dietary cholesterol. Conversion from dietary to blood serum cholesterol varies for each person and ranges from 20% to 90% of the amount consumed.

Blood serum cholesterol levels should remain below 200 mg per deciliter to be considered "normal" according to recent studies. This number represents only 10% of the total amount of cholesterol in the body. The rest is contained in cell membranes and other body tissues. The National Cholesterol Education Program recommends a dietary cholesterol consumption of no more than 300 mg per day. The body requires no intake of cholesterol but manufactures all the cholesterol it needs from dietary fat and produces about 1000 mg per day.

There are basically two types of Cholesterol transport systems, Low Density Lipoproteins (LDL) and High Density Lipoproteins (HDL). Each type is a fat carrying protein. LDLs, the bad cholesterol carrier, transports cholesterol to the cells and are associated with atherosclerosis or hardening of the arterial walls. HDLs, the good cholesterol carrier, transports cholesterol to the liver where it is processed for excretion or broken down for other uses. Monosaturated and Polyunsaturated fats lower LDL levels and increase HDLs whereas Saturated fats increase LDL levels. The goal is therefore to minimize the LDL cholesterol by reducing the dietary intake of saturated fats. The food label may tout "no cholesterol" but the body manufactures cholesterol from saturated fats.

Atherosclerosis is a condition where the arteries become occluded. This is caused by a lesion which develops just under the inner lining of the arterial wall. This swelling, composed of fibrous protein, accumulates LDL carried cholesterol as blood platelets begin to stick to the damaged area. This accumulation reduces the inner diameter of the artery and subsequently leads to a decreased flow of blood through the artery. The platelets continue to accumulate at the injured site until a clot is formed, blocking all blood flow to the heart. The area of the heart normally being fed by this artery becomes injured. This is known as a heart attack.

Cardiovascular health is a result of proper diet and exercise. Genetics may predispose someone to high blood pressure or heart disease, however, diet, exercise and medication can lessen the impact and improve longevity.

source : Training Manual & Certification Course, Fitness ABCs
written by Chuck Krautblatt, Personal Trainer and Aerobics Instructor
1995, 1998

Nutrients: Proteins, Carbohydrates, Fat, Cholesterol, Vitamins, Minerals, + water.

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