Oct. 16, 2000 (Boston) -- Too much coffee can give you the shakes, but a moderate amount of java may protect you from Parkinson's disease (PD) and its symptoms of uncontrolled trembling and involuntary movements, report Harvard University researchers in a poster presentation here at the 125th annual meeting of the American Neurological Association.
Among nearly 50,000 men who were followed for 10 years, those who consumed the most caffeine, primarily in coffee, had the lowest risk for developing Parkinson's disease. But the relationship between caffeine and PD was less clear in a related study of more than 88,000 women followed for two decades, report Alberto Ascherio, MD, and colleagues from the Harvard School of Public Health in Boston.
But before you rush out for that double espresso in hopes of staving off Parkinson's, be aware that the results are only preliminary and suggestive of further promising lines of research, cautions Ascherio in an interview with WebMD.
"Unfortunately, there are no real insights from this study. It should be of interest only within the scientific community. We don't know enough about the effects to make recommendations for patients," says Ascherio, an associate professor of nutrition and epidemiology at Harvard.
The researchers found that cigarette smoking also provides a protective effect against PD, a fact that should be comforting to people who can't seem to face the morning without a mug in one hand and a butt in the other. They don't, however, recommend taking up cigarette smoking or coffee drinking just to prevent a theoretical risk of Parkinson's.
Caffeine, alcohol, and tobacco stimulate the release of a brain chemical called dopamine, which is responsible for that feeling of pleasure we get from these substances. Dopamine is lacking in the brains of people with Parkinson's disease. They may not get the "rush" that comes with a cup of French roast and may, therefore, not be heavy coffee consumers to begin with.
The current study followed participants in two mammoth-scale, long-term studies of health professionals. In each study, participants filled out detailed questionnaires every 4 years that asked them about their lifestyles, habits, diets, and other health-related factors. The idea was to see if anything they did -- or failed to do -- might have an effect on their overall health.
Among the more than 130,000 subjects in the combined studies, the Harvard researchers identified 288 cases of PD. They found that men who were in the top fifth of caffeine consumers had about half the risk of developing PD as those in the bottom fifth. Among women, however, the relationship was less clear.