March 9, 2004 -- Drinking more than three cups of coffee a day may give you the jitters, but it may also reduce the risk of type 2 diabetes, a new study suggests.
Finnish researchers found people who drank at least 3-4 cups of coffee a day had a nearly 30% lower risk of developing type 2 diabetes.
The study, published in the March 10 issue of The Journal of the American Medical Association, shows the protective effects of coffee on diabetes risk increased as coffee consumption increased, especially among women.
Women who drank more 10 or more cups of coffee a day had a 79% lower risk of type 2 diabetes, and men who drank the same amount had a 55% lower risk.
Coffee May Lower Type 2 Diabetes Risk
Researchers say only a few studies have looked at the relationship between coffee consumption and type 2 diabetes risk, even though coffee is the most consumed beverage in the world. Those studies have also suggested that coffee lowers the risk of diabetes.
But in this study, researchers examined the effects of drinking coffee on type 2 diabetes risk among a large group of Finnish men and women, who have the highest per capita coffee consumption in the world.
Researchers combined surveys conducted in 1982, 1987, and 1992 of nearly 15,000 healthy Finnish men and women aged 35 to 64 who had no history of diabetes or other chronic diseases at the start of the study.
They found that the risk of developing type 2 diabetes decreased as the amount of daily coffee consumed increased, and those effects were stronger among women than men.
Men who drank 3-4 cups of coffee a day had a 27% lower risk of diabetes.
- Women who drank 3-4 cups of coffee a day had a 29% lower risk of diabetes.
- Men who drank 7-9 cups per day had a 33% lower risk of diabetes.
- Women who drank 7-9 cups per day had a 61% lower risk of diabetes.
Too Soon to Reach for a Second Cup
Researchers say the mechanism behind coffee's beneficial effects in reducing type 2 diabetes risk is unknown, but there are several possible explanations.
For example, coffee contains several ingredients, such as magnesium, antioxidants, phytoestrogens, and others, which may affect blood sugar regulation. Caffeine is also thought to affect insulin secretion. Abnormalities in insulin levels and its actions in lowering blood sugar are risk factors for type 2 diabetes.
"Expanded investigation is required to explore these mechanisms, including randomized controlled trials," write researcher Jaakko Tuomilehto, MD, PhD, of the National Public Health Institute in Helsinki, Finland, and colleagues.
But until coffee's effect on diabetes risk is fully understood, researchers say it's too soon to recommend that people increase their daily dose of coffee. Other studies have suggested that drinking large amounts of coffee may pose other health risks, such as causing blood pressure levels to spike.