That morning cup of coffee may lower the risk of type 2 diabetes

Feb 13 2006

According to a new study, by researchers at the Harvard School of Public Health in Boston, Massachusetts, drinking coffee lowers the risk of type 2 diabetes.

Dr. Rob M. van Dam and colleague Dr Hu examined the association between habitual coffee consumption and risk of type 2 diabetes and related outcomes by monitoring a group of 88,259 women in the U.S. enrolled in the longterm Nurses Health Study.

The researchers reviewed studies of habitual coffee consumption and risk of type 2 diabetes but excluded studies of type 1 diabetes, animal studies, and studies of short-term exposure to coffee or caffeine.

That finally entailed 15 epidemiological studies.

The researchers examined the womens' consumption of coffee and other caffeine-containing foods and drinks in 1991, 1995, and 1999.

They noted in the period from 1991 to 2001, 1,263 cases of type 2 diabetes.

The researchers say that drinking coffee was linked to a decreased risk of type 2 diabetes.

It seems that one cup of coffee a day equated to a 13 percent reduction of type 2 diabetes risk compared with 42 percent reduction for two to three cups a day, and 47 percent reduction for four or more cups a day.

Tea consumption surprisingly was linked with only with a 12 percent lower risk in those who drank four or more cups a day, suggesting say the team, that caffeine is not the major factor influencing the risk.

However it seems that not all coffee has the same effect.

Filtered coffee and instant coffee produced a similar reduction in risk while espresso or percolator coffee did not.

In conclusion the researchers say that a moderate consumption of both caffeinated and decaffeinated coffee may lower risk of type 2 diabetes in younger and middle-aged women.

In a 2004 study by Hu and colleagues from the Department of Nutrition and Epidemiology at the Harvard School of public Health, it was found that women who drank six or more cups of coffee were 30 percent less likely to have type 2 diabetes compared with the nondrinkers, and men, by drinking six or more cups of caffeinated coffee had a 30 percent lower risk of type 2 diabetes.

In their research the scientists monitored 41,934 men from 1986 to 1998 and 84,276 women from 1980 to 1998 for their intake of regular and decaffeinated coffee using food frequency questionnaires every two to four years.

The study did not look at other risk factors.

Hu's study also found that decaffeinated coffee had similar, but less effects compared with regular coffee.

The researchers admit they are unsure exactly how coffee affects the risk of type 2 diabetes and warn against sudden increased coffee consumption to prevent the disease.

They say more research needs to be done to clarify the link between drinking coffee and the risk of type 2 diabetes.

There are apparently 20 million Americans with type 2 diabetes.

The study is published in the February issue of Diabetes Care, a journal of the American Diabetes Association.

Dr. Hu's study was published in the January 6, 2004 issue of the Annals of Internal Medicine.