Studies have found that a combination of chemicals in coffee beans may affect metabolism — the chemical processes in the body that converts or uses energy. One chemical, chlorogenic acid, may lower blood sugar levels. Caffeine, however, might not make a difference.
Researchers recently discovered that both caffeinated and decaffeinated coffee are tied to reducing diabetes risk, and the more people drink, the lower their risk appears to be.
"Ask your doctor about adding more coffee to your diet."
Frank Hu, MD, professor of epidemiology and nutrition at the Harvard School of Public Health, and his team conducted detailed analysis of 28 studies, representing 1.1 million total participants and 45,335 cases of type 2 diabetes. Patients were followed for durations of 10 months to 20 years.
Compared to those who rarely or never drank coffee, coffee drinkers had a lower diabetes risk, which was inversely related to how much they drank.
One cup a day translated to about an 8 percent lower risk on average. Two cups cut the risk by 15 percent. Three cups dropped the risk by 21 percent. Four cups equaled a 25 percent risk cut, five cups reduced the risk by 29 percent, and six cups lowered the risk by a third.
The scientists discovered that those who drank one cup a day of caffeinated coffee were 9 percent less likely to get diabetes while those who had one cup of decaffeinated a day were 6 percent less likely.
Dr. Hu and his team noted that several chemicals in coffee may improve glucose metabolism, and they highlighted chlorogenic acid. “Chlorogenic acid may reduce glucose absorption in the intestines,” the authors wrote. “Coffee is also a good source of magnesium, which has been associated with a lower risk of type 2 diabetes.”
With diabetes, the body is not properly using blood sugar because of problems with insulin resistance. Insulin is a hormone made by beta cells in the pancreas. Insulin helps cells use and store glucose for energy. Without insulin, the glucose stays in the bloodstream.
The authors wrote that, compared to those without diabetes, people with type 2 diabetes were two to five times more likely to have a heart attack and two to three times more likely to have a stroke.
They concluded that higher consumption of coffee is associated with a significantly lower risk of diabetes, and both caffeinated and decaffeinated coffee cut the chances of getting the disease.
The study was published in the February 2014 issue of Diabetes Care. Funding was provided by a grant from the National Institutes of Health.