Vol. 2, No. 4 , 1996, Page 1&3 
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Vol. 2, No. 4 , 1996, Page 1&3 |
Can a diet of rice cakes, lettuce, and bran flakes be bad for your brain? It's not a frivolous question: new reports add to earlier evidence tentatively linking low cholesterol levels to depression, suicide, and an increased risk of violent death.
The link was first suggested when researchers discovered that although death rates from heart disease are lower in people with low cholesterol, overall death rates remain the same. The reason, according to several studies: although cardiac death rates drop in patients treated with cholesterol- lowering therapies, deaths caused by violence, suicide, and accidents rise.
"The association was initially regarded as an anomalous occurrence," Ann Ryman noted in the British Medical Journal, "but it has been too consistent to be dismissed. It has appeared in studies irrespective of whether drugs or diet were used to lower cholesterol concentrations."
Several studies suggest that low cholesterol indeed influences behavior in ways that could contribute to violent death. More than a decade ago, Matti Virkkunen et al. found that serum cholesterol levels were markedly lower than normal in chronically violent and homicidal offenders (and particularly in young offenders, and those who abused alcohol). In 1993, Marc Hillbrand and Hilliard Foster, studying violent criminals in a forensic hospital, reported an association between lower cholesterol levels and more severe aggression. In addition, animal studies indicate a relationship between low cholesterol and increased aggression.
Not all research, however, links low cholesterol to negative behavior. Jose Santiago and James Dalen reviewed several studies and found that while some showed an association between low cholesterol and aggression or other behavior problems, others did not-and at least one found that a low cholesterol diet decreased depression and aggressive hostility.
Several new studies, however, support the theory that low cholesterol is a risk factor for suicide, depression, and violent behavior. Among recent findings:
--Mahmoud Zureik et al. reported in September that the risk of suicide is elevated in men with low cholesterol levels, and those whose cholesterol levels dropped over time, compared to men with higher cholesterol. The researchers studied more than 6,000 men between the ages of 43 and 52.
--Barbara Ulm and colleagues studied 20 pregnant women with no known mental, physical, financial, or marital problems. Those whose cholesterol concentrations dropped the most after delivery, the researchers reported in September, were the most likely to experience postpartum depression.
--In 1995, Hillbrand and colleagues compiled data from the medical records of a new group of 106 violent patients at a forensic hospital. They found that as a group, these violent patients had cholesterol levels significantly lower than population norms. When they divided their patients into high-cholesterol and low-cholesterol groups, they found that "patients with low cholesterol levels engaged in more frequent aggressive behavior but showed no difference in severity of aggression." The relationship between aggression frequency and cholesterol was curvilinear, they say, "with the most frequent acts of aggression committed by patients with moderately low cholesterol levels."
Why would low cholesterol lead to aggression, suicide, or depression? One theory is that low cholesterol is associated with a decrease in serum free tryptophan, the primary building block of the brain chemical serotonin. Low levels of serotonin are strongly linked to depression, suicide, and impulsive aggression.
Paul Steegmans et al. found that plasma serotonin concentrations are lower in men with naturally low serum cholesterol concentrations than in men with average cholesterol concentrations. "This," the researchers say, "supports the hypothesis that serotonin metabolism may be implicated in the observed association between low cholesterol concentrations, behavioral changes, and violent death."
"Is cholesterol a mood-altering lipid?," Science News, Vol. 150, No. 12, September 21, 1996.
"Low serum cholesterol concentration and serotonin metabolism in men," Paul H. A. Steegmans, Durk Fekkes, Arno Hoes, Annette Bak, Emiel van der Does, and Diederick Grobbee, British Medical Journal, Vol. 312, No. 7025, January 27, 1996.
"Serum cholesterol and aggression in hospitalized male forensic patients," Marc Hillbrand, Reuben T. Spitz, and Hilliard G. Foster, Journal of Behavioral Medicine, Vol. 18, No. 1, 1995. Address: Marc Hillbrand, Whiting Forensic Institute, Box 70, Middletown, CT 06457.
"Cholesterol, violent death, and mental disorder: the association deserves further, specific study," Ann Ryman, British Medical Journal, Vol. 309, No. 6952, August 13, 1994.
"Cholesterol and violent behavior," Jose M. Santiago and James E. Dalen, Archives of Internal Medicine, Vol. 154, No. 12, June 27, 1994.