New research published in the December issue of Archives of Internal Medicine has found that consuming coffee reduces the risk of diabetes. The findings from this meta-analysis, based on over 500,000 individuals with over 21,000 cases of new-onset diabetes, confirm an inverse relationship between coffee consumption and subsequent risk of type 2 diabetes. There was also an inverse relationship between consumption of decaffeinated coffee and tea, and risk of diabetes.
Individuals who drank three to four cups of coffee per day had an approximately 25 percent lower risk than those who drank between zero and two cups per day. In addition, in the studies that assessed decaffeinated coffee consumption, those who drank more than three to four cups per day had about a one-third lower risk of diabetes than those who drank none. Those who drank more than three to four cups of tea had a one-fifth lower risk than those who drank no tea.
The beneficial effects are unlikely to be solely related to caffeine. Coffee is a source of numerous compounds that improve glucose metabolism in animal studies, including chlorogenic acids and lignans. Chlorogenic acid may delay glucose absorption in the intestine, and may inhibit glucose-6-phosphate activity. Also, the antioxidant content of coffee may have beneficial effects on glucose metabolism. For example, the lignans in coffee may affect glucose metabolism through its antioxidant properties.
If the beneficial effects of drinking coffee and tea were observed in interventional trials to be real, the implications for the millions of individuals who have diabetes mellitus, or who are at future risk of developing it, would be substantial, conclude the authors of this study. For example, the identification of the active components of these beverages could open up new therapeutic options for the primary prevention of diabetes mellitus. The authors also envisage the possibility that patients most at risk for diabetes could be advised to increase their coffee consumption, in addition to increasing activity and losing weight.
The number of people with type 2 diabetes has increased at an alarming rate over recent years and the trend looks set to continue; in 1985 an estimated 30 million people worldwide had diabetes; in 2000 the figure had increased to over 150 million; and by 2025 it has been estimated that the figure will rise to almost 333 million. Any strategies that might help to prevent this condition are to be welcomed. However, although coffee drinking appears to be independently related to a decreased risk of type 2 diabetes, regular physical activity, a healthy diet and avoidance of excess weight gain should still be the mainstay of prevention and treatment of this condition.
Huxley R et al. Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus. A systematic review with meta-analysis. Arch Intern Med 2009; 169 (22): 2053-2063.