A report in Preventive Medicine showed that having a very low cholesterol level is not unhealthy. Young men with low blood cholesterol levels were the ones most likely to enjoy good health and live long lives. The only ones with low cholesterol levels who were likely to die early were those who smoked.
Previous studies have associated low blood cholesterol levels with liver cancer, lung disease, depression, alcoholism and suicide. Newer data show that a low cholesterol may be associated with cancer, but does not cause it. Before a person develops the symptoms of cancer, he often loses interest in eating and loses weight, which causes his cholesterol to drop. The most famous study on the effects of cholesterol on health is from Framingham, Massachusetts. Blood cholesterol levels were tested every two years. Researchers showed that cholesterols started to fall up to 8 years prior to a person dying of cancer, and that those with the greatest fall in cholesterol in a four-year period were those who were most likely to develop cancer.
A study from Russia showed that men who have low blood cholesterol levels are more likely to drink, and have far less education than men with normal or high cholesterol levels. Lacking formal education, drinking heavily and getting into accidents caused both the low cholesterol and the early deaths. Lung disease, alcoholism, certain types of cancers and many other illnesses suppress appetite, so people eat less, causing their blood cholesterol levels to drop significantly.
There is no evidence that a low blood cholesterol causes you to die early. If you have a very low blood cholesterol level, your doctor could check you for a hidden cancer, addiction to alcohol, cigarettes or drugs, or other disease. If none is found, you should be delighted and usually can expect to live a long time. On the other hand, if your cholesterol is high, you should start to worry because you are at increased risk for a heart attack and certain types of cancers and should start immediately on a cholesterol-lowering diet that is high in plants and low in refined carbohydrates; see my modified DASH diet.