Cholesterol: The Good, The Bad and The Rest

The word 'cholesterol' derives from several Greek words: 'chole' (bile); 'stereos' (solid) and the chemical suffix '-ol' for an alcohol. It was first identified in solid form in gallstones in 1784, but is present in all animal tissue and to some extent in plant membrane too. It is not only ingested but also synthesised by the body. It plays a vital role in many biological processes, but is best known for its association with cardiovascular disease.

In recent years, the somewhat imprecise, popular terms "good cholesterol" and "bad cholesterol" have been coined to refer to LDL (low-density lipoprotein) and HDL (high-density lipoprotein), although cholesterol does not have two different forms. It is, however, transported around the body combined with different lipoproteins; the best known of which are LDL and HDL. Cholesterol is not directly soluble in blood, but can be transported in the circulatory system when enclosed in one of the varieties of lipoprotein, which are spherical particles having an exterior composed mainly of water-soluble proteins. The average person weighing 10-11 stones (68 kg) has a total body content of about 35 grams of cholesterol; a typical daily internal production of about 1 gram, and typical daily dietary intake of 200 to 300 mg. If one ingests more cholesterol than the body needs, then internal production decreases and vice versa.

One of the most common problems of high concentrations of cholesterol is a gallstone, although other less common types of gallstones are produced too. The most well-known and much more serious condition produced by high cholesterol levels is higher levels of atheroma (artherosclerosis), which in turn, is the prime cause of coronary heart disease. On the other hand, very low levels of cholesterol are associated with cancer, cerebral hemorrhage and depression - although the evidence is not conclusive.

The most common animal protein sources of cholesterol are beef, egg yolks and (surprisingly) shrimps. Many people falsely believe that it is not present in plant cells, but fairly high levels are present in peanuts and flax (oil) and it is present in all plant membrane.

The only known method of treating 'high cholesterol' is to increase the HDL levels while decreasing the LDL levels. Basically, LDL carries cholesterol out into the bloodstream, where high levels can cause build-ups on the arterial walls and HDL carries it back to the liver where it does no known harm.

High cholesterol levels can be hereditary but, in an overwhelming majority of cases, something can be done. Obesity, diabetes, poor diet, lack of exercise stress and smoking all promote higher levels. While there is no silver bullet, reduction in weight through exercise comes close as it would reduce the chances or effects of diabetes, lower blood pressure and reduce stress. Stopping smoking and eating less saturated fat comes next and a combination of the above methods will go a long way to normalising cholesterol levels. If all else fails, there are prescription drugs available, which can control or reduce levels. However, there are some risk factors that cannot be controlled. These include age (being over 45 years for men and over 55 years for women) and family history of early heart disease (father or brother having serious problems before age 55; mother or sister before age 65).

Michael Russell Your Independent guide to Cholesterol [cholesterol-guided.com]