Is Too Little Cholesterol Bad For You?

By now even the most reclusive of hermits is probably aware of the
link between heart disease and high cholesterol levels. But having too
little of the fatlike substance may have its drawbacks, too. Studies
suggest that people with low levels of cholesterol are at increased risk
for depression.

Some years ago scientists discovered that people with low
cholesterol seem to be more likely to commit suicide. That finding led
researchers to wonder if depression might also be connected with
cholesterol levels. A 1993 study, in fact, found just such an
association, at least for men over age 70. But another group of
scientists -- also studying elderly men -- saw no such effect.

Researchers at the University of Kuwait have linked low cholesterol
levels to depression in both men and women, and in all age groups.
Studying 100 depressed individuals being treated at Kuwait's only
psychiatric hospital, pathologist Samuel Olusi, M.D., and psychiatrist
Abdullahi Fido, M.D., found that the patients had lower levels of
cholesterol in their blood than did the nondepressed controls.
(Incidentally, eating cholesterol-rich foods doesn't raise our
cholesterol levels very much; saturated fats, from which our bodies
manufacture cholesterol, are a greater contributor to the
problem.)

Because cholesterol may be an important component of brain cell
membranes, it's possible that a lack of the substance reduces neurons'
ability to process serotonin, the neurotransmitter that helps regulate
mood. This malfunction, in turn, could contribute to depression. However,
Olusi and Fido note that "our study did not show that lowering serum
cholesterol causes depression." It's possible that depression changes a
person's eating habits, so that his or her cholesterol levels fall after
the illness sets in. The verdict then: The cholesterol-depression link
remains intriguing but still not settled.