A high blood level of fat—the correct medical term for it is hyper-lipidemia—is a broad term covering several conditions in which one or other of the different types of fat in the blood is raised. I have referred throughout the book to cholesterol, but this is a simplification.
It may be helpful here to explain the jargon around cholesterol and blood lipids. Cholesterol and triglycerides, the two prominent fats, or lipids, are carried around in the bloodstream by lipoproteins, which are combinations of protein and fat. The lipoproteins are classified according to their densities, so that very low-density lipoproteins are VLDL, low-density lipoproteins are LDL, intermediate-density lipoproteins are IDL, and high-density lipoproteins are HDL, sometimes called the “good” cholesterol.
The higher the LDL in the blood, the greater the risk of angina and heart attack; it seems that LDL is the substance that carries the cholesterol and triglycerides into the atheromatous plaques. In contrast, the higher the HDL, the lower the risk of heart attack. HDL seems to carry away the cholesterol from the bloodstream into the liver, where it is broken down into bile acids and excreted in the feces. VLDL does not appear to affect coronary risk much, if at all; IDL may make it worse, but LDL is the main villain.
There are at least five different forms of hyperlipidemia, and several different types of lipid-lowering drugs available to correct them. Among them are:
• Niacin and other nicotinic acid derivatives
• Fibrates
• Statins
• Marine triglycerides
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