Coffee Prevents Diabetes

Whenever researchers compare coffee drinkers with abstainers, there’s a consistent connection between a few jolts of java each day — with or without caffeine — and less risk of Type 2 diabetes. No one has figured out exactly why, but some clues are emerging.

When diabetes risk is assessed, the major markers are blood sugar levels and how well the hormone insulin functions. Coffee doesn’t seem to produce an immediate improvement in either one of these, but by testing for more subtle changes, researchers are beginning to identify ways the brew bestows its benefits.

One study, led by researchers at the Harvard School of Public Health, compared the effects of decaf, regular coffee, and no coffee on diabetes risk among 41 middle-aged men and women who were overweight. During a period of eight weeks, decaf and regular coffee each improved different markers of risk for Type 2 diabetes.

For example, caffeinated coffee increased levels of adiponectin, a protein made by fat cells that protects against diabetes. Decaf lowered levels of a different protein — fetuin-A, made by the liver — that contributes to development of the disease. In both cases, such changes also reduce the risk of plaque deposits in arteries.

Other research has found that coffee has a beneficial effect on hormones in a way that reduces diabetes risk. And overall, studies that support coffee’s ability to prevent the disease — with and without caffeine — have looked at a total of nearly 700,000 people.

The preventive effects of coffee on Type 2 diabetes have been observed in long-term coffee drinkers. Although individual circumstances vary, researchers who analyzed available studies concluded:

• For caffeinated coffee, people who drank three to four cups daily were 25 percent less likely to develop Type 2 diabetes than those who drank zero to two cups daily.

• For decaf coffee, people who drank more than three to four cups daily had about 33 percent lower risk than those who drank none.

Prevention vs. Cure

For those who already have Type 2 diabetes, coffee doesn’t necessarily work the same way. There is no known danger of decaf coffee, but in one small study, caffeine by itself (in capsules) triggered spikes in blood sugar among diabetics.

Aside from caffeine, coffee contains magnesium and a variety of beneficial antioxidants, and the combined effect may be different from caffeine alone. So far, preliminary studies show that regular coffee may elevate blood sugar among diabetics but this issue has not been well studied.

Getting the Benefits

Bottom line, coffee doesn’t replace the need for exercise and a healthy way of eating. And, coffee drinks with cream, sugar, or flavored syrups can pack a lot of calories, so they aren’t a healthy option.

Some people are sensitive to caffeine, even to the miniscule amounts that are present in decaf versions. In those cases, any kind of coffee won’t be helpful.

But for most of us, coffee — caffeinated, decaf, or both — can be a pleasant drink that helps us stay in good shape.