Researchers have found that each additional cup of coffee consumed in a day was associated with a 7 percent reduction in the excess risk of diabetes.
Individuals who drank three to four cups 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.
That the apparent protective effect of tea and coffee consumption appears to be independent of a number of potential confounding variables raises the possibility of direct biological effects, the authors write. Because of the association between decaffeinated coffee and diabetes risk, the association is unlikely to be solely related to caffeine. Other compounds in coffee and tea including magnesium, antioxidants known as lignans or chlorogenic acids may be involved, the authors note.
If such beneficial effects 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, they conclude. 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 findings also pose the question of whether patients most at risk for diabetes mellitus may in the future be advised to increase their consumption of tea and coffee in addition to increasing their levels of physical activity.
