The Bad News About Coffee and Your Health

In the past few months, major health studies and surveys have concluded that coffee helps reduce heart disease in women, reduces the risk of some types of cancer, helps athletes rebuild energy stores faster after exercise and may hold the key to halting the progression of lupus. With all the rosy news about coffee being touted by coffee roasters and distributors around the world, it’s easy to miss the occasional study that has bad news for coffee drinkers.

Coffee and Infertility

A recent Dutch study, for instance, found a correlation between high rates of coffee consumption (four or more cups of coffee a day) and difficulty conceiving for women with fertility problems. The study was presented by Dr. Bea Linsten from Radboud University in Nijmegan, The Netherlands. It involved nearly 9,000 women who had undergone In Vitro Fertilization. Dr. Linsten’s team followed their progress and studied the lifestyle factors that might have an influence on their attempts to conceive. Their findings were that women who drank four or more cups of coffee or tea a day reduced their chances of a natural conception by 26%.

Drinking alcohol to excess also reduced the chances of conceiving naturally, as did obesity and smoking cigarettes.

Coffee and Rheumatoid Arthritis

In a Finnish study, doctors found that drinking five or more cups of coffee a day significantly increases the risk of developing rheumatoid arthritis. The study was conducted by the National Public Health Institute of Helsinki and involved over 20,000 from two different surveys. The results were published in the Annals of the Rheumatic Diseases Journal.

In one of the two studies, researchers found that the risk of rheumatoid arthritis was twice as high for those who drank more than five cups of coffee daily; even after all other risk factors were adjusted. Those who drank more than eleven cups of coffee daily increase their risk of developing rheumatoid arthritis to fifteen times that of a person who doesn’t drink coffee.

Coffee and Diabetes

Two separate studies suggest that drinking coffee may interfere with the body’s insulin production or sugar metabolism. A 2004 study undertaken at Duke University tested the blood sugar levels of fourteen participants after a meal with and without caffeine consumption. The researchers found that blood sugar levels were significantly higher after a meal consumed with caffeine than they were after a meal without caffeine.

In a second study at Duke, researchers implanted a small glucose monitor under the skin so that they could track the effects of caffeine over the course of 72 hours in subjects going about their normal daily routines. They found that on the days that the subjects were given caffeine pills, blood sugar was significantly higher after meals. These studies suggest that caffeine may increase the body’s resistance to insulin, which regulates sugar metabolism.

Other medical experts are quick to point out that the number of participants in these studies is small – 14 participants in one and 10 in the other – and that the researchers used caffeine in pill form rather than in coffee. Coffee contains many other components which may actually protect the body from diabetes.