The cholesterol dilemma
IT is known since long that high blood cholesterol levels could cause heart ailments. But recently, researchers report that its low levels could be bothersome too. Lower blood cholesterol levels have been held responsible for an increase in suicidal tendency and aggressive behaviour (Current Science, Vol 69, No 6).
A spate of research papers that have appeared in the course of the past few years have revealed these numerous effects of blood cholesterol levels. A study conducted by M F Muldoon in the UK in 1990, found that patients with high serum cholesterol levels were put on medication to lower its levels.
The studies that followed did not indicate any reduction in mortality levels as was expected from them, even though there was a reduction in deaths related to heart diseases. The conclusions that were naturally drawn were that with the reduction of serum cholesterol, mortality from other causes increases.
According to another study carried out in Sweden by G Lindberg in 1992, men with low serum cholesterol showed a higher mortality rate. After screening more than 350,000 men, higher mortality resulting from noncardiac sources was found to be mainly due to suicides, traffic accidents and aggression".
More recent studies conducted in 1995 by J Golier in the US, propose that low blood cholesterol is "a potential biological marker of suicidal risk." The explanation offered for the increased suicide rates is interesting. It is suggested that lower cholesterol levels in the blood stream reduces the brain serotonin level, which in turn leads to poorer suppression of behavioural impulses such as suicide and aggression.
Further, researchers present evidence that noncardiac deaths, particularly suicides, take place not only in patients on cholesterol- lowering drugs, but also in people with naturally low levels of it. Quite surprisingly, the consequences of having a lower blood cholesterol level seems to be more marked in men than in women - a phenomenon that researchers are unable to account for.
Meanwhile, doctors had better think twice before advising their patients to keep their blood cholesterol levels low.