Drinking Coffee Lowers Diabetes Risk by 56%

LOS ANGELESWomen who drink at least four cups of coffee a day are less than half as likely to develop diabetes as non-coffee drinkers, according to research published in the journal Diabetes. The finding suggest caffeine increases plasma levels of a protein called sex hormone-binding globulin (SHBG) that protect against type 2 diabetes.

"It seems that SHBG in the blood does reflect a genetic susceptibility to developing type 2 diabetes," the researchers said. "But we now further show that this protein can be influenced by dietary factors such as coffee intake in affecting diabetes risk the lower the levels of SHBG, the greater the risk beyond any known diabetes risk factors."

Researchers at UCLA identified 359 new diabetes cases matched by age and race with 359 apparently healthy controls selected from among nearly 40,000 women enrolled in the Women's Health Study. They found women who drank four cups of caffeinated coffee each day had significantly higher levels of SHBG than did non-drinkers and were 56% less likely to develop diabetes than were non-drinkers. Those who also carried the protective copy of the SHBG gene appeared to benefit the most from coffee consumption.

When the researchers controlled for blood SHBG levels, the decrease in risk associated with coffee consumption was not significant. The findings suggest that it is SHBG that mediates the decrease in risk of developing type 2 diabetes. Consumption of decaffeinated coffee was not significantly associated with SHBG levels, nor diabetes risk.