Yep, coffee is still good for you

There have been conflicting studies about the effects of coffee-drinking on overall markers of inflammation as well as the function of the endothelium (the lining of the arteries). The theory is that inflammation can cause a lack of proper responsiveness of the artery as far as relaxation, as well as impairing its ability to respond to injury and inflammation. This can lead to cardiovascular disease, and is one of the reasons that baby aspirin is prescribed for daily intake to persons who have had heart attacks. Similarly, anti-oxidants have a complex, anti-inflammatory effect on the endothelium.

A recent study published in the American Journal of Clinical Nutrition (2006;84(4):888-93) included two groups of women from the Nurses' Health Study, a study established in 1976 that included over 121,700 women and continues to the present day with questionnaires sent to the participants every two years. The published study included 730 healthy women who had not been diagnosed with cardiovascular disease, cancer, or type 2 diabetes mellitus in 1989-90. A second group of 663 women had a confirmed diagnosis of type 2 diabetes in 1990, but not cardiovascular disease or cancer, and were not insulin-dependent (insulin has anti-inflammatory properties).

In 1986 and 1990, the questionnaire sent to the participating nurses included questions about food intake and very specific questions about the amount of coffee they drank. Coffee intake was broken down into caffeinated and decaffeinated, as well as into 9 levels of intake: never, 1-3 cups per month, 1 cup per week, 2-4 cups per week, 5-6 cups per week, 1 cup per day, 2-3 cups per day, 4-5 cups per day, and 6 or more cups per day. Overall, 77% of the healthy women and 74% of the diabetic women drank at least one cup of caffeinated coffee per month, and 75% of the healthy women and 63% of the diabetic women drank at least 1 cup of decaffeinated coffee per month.

The participating nurses' blood was drawn in 1990 and analyzed for markers of inflammation and endothelial dysfunction. They found that the more caffeinated coffee that diabetic women drank, the lower were those markers of inflammation and endothelial dysfunction. On the other hand, higher levels of decaffeinated coffee intake by the healthy women was associated with lower levels of inflammatory markers and endothelial dysfunction.

What this means for you:

These results are consistent with previous studies that show that coffee intake is linked with lower mortality rates in general (News Bite, 5/12/06) and reduced risk of diabetes (News Bite, 7/5/06). Coffee continues to be the single largest source of anti-oxidants in our Western diet, so increase your anti-oxidant intake by drinking coffee instead of soda.

First posted: October 17, 2006