One after another, foods that were once cast as dietary bad guys have seen their images rehabilitated. Nuts, eggs, avocados, even chocolate have been welcomed back into the kitchen as new research has dispelled worries and even pointed to potential health benefits.
The latest candidate for a makeover is coffee.
In the 1970s and 1980s, coffee was blamed for a variety of ills, from high blood pressure to cancer. "The focus of early research was almost always on finding fault," says Harvard Medical School epidemiologist Alan Leviton. "People tended to think of coffee as a vice, so the bias was that there had to be something wrong with it."
But very few of those worries have been born out by research, Leviton says. "And now we're starting to see evidence of some intriguing benefits associated with coffee."
Findings published over the last five years suggest that coffee may protect against gallstones, diabetes and even Parkinson's disease.
Interest in the link between coffee and gallstone disease first began to percolate in the early 1990s, when laboratory research demonstrated that caffeine can reduce the size of these small crystallized stones, and perhaps prevent them from forming in the first place. "What we didn't know was whether coffee drinkers out in the real world would get any benefit," says nutrition researcher Michael Leitzmann.
In findings published in 1999, he and colleagues at the Harvard School of Public Health looked at data from 46,008 men who are being followed in the Health Professionals Follow-up Study. Coffee drinkers, they found, were significantly less likely to develop gallstones than men who didn't drink the beverage. In 2002, the same team looked at 80,898 women who are part of the Women's Health study. Among women, too, coffee drinkers tended to have less risk of developing gallstones.
The evidence was especially persuasive because the effect was dose-dependent. "The more coffee people drank, the lower their risk of developing gallstones," Leitzmann says. The risk fell 13% among those who drank one cup a day, 21% for people who drank two to three cups, and 33% for people who drank four or more cups a day.
Decaffeinated coffee didn't protect against gallstones, however, suggesting that the active component may be caffeine.
Caffeine also appears to be responsible for another potential benefit for coffee drinkers -- a lowered risk of Parkinson's disease.
