WASHINGTON (Reuters) – People who gulp several cups of coffee a day can greatly lower their risk of developing diabetes later in life, even if they are overweight, according to a U.S. study published on Tuesday. The study of 125,000 people suggests that caffeinated coffee — not caffeine-free — may affect the body’s metabolism in positive ways, the researchers at the Harvard School of Public Health said.
Men who drank more than six cups of full-caffeine coffee a day cut their risk of diabetes by more than half over 12 to 18 years, the study found. Women who drank that much coffee reduced their risk by 30 percent.
Writing in the Annals of Internal Medicine, the researchers said it was not clear what caffeinated coffee does to reduce the risk of type-II or adult-onset diabetes.
An estimated 15 million Americans have type-II diabetes, the sixth leading cause of death in the United States. Linked strongly with being overweight and with a lack of exercise, diabetes can lead to heart disease, stroke, blindness, limb loss and other disabilities.
Type-I or juvenile diabetes is a different disease, affecting an estimated 1 million to 2 million Americans. It is caused by the destruction of key pancreatic cells.
In type-II diabetes, the body loses its ability to use insulin properly to metabolize food, especially sugar.
The researchers, led by Dr. Eduardo Salazar-Martinez, Dr. JoAnn Manson and others at Harvard and Brigham and Women’s Hospital in Boston, said caffeine is known to affect how the body handles sugar.
Caffeine also raises metabolism, they said, and may affect other aspects of metabolism such as fat oxidation and mobilization of glycogen in muscle.
“Coffee contains many other ingredients that may contribute to the inverse association,” they wrote in their report.
“For example, coffee contains a substantial amount of potassium; niacin; magnesium; and antioxidant substances, such as tocopherols and phenol chlorogenic acid,” they added.
“These constituents may have beneficial effects on the development of diabetes through synergistic or independent actions on glucose metabolism and insulin resistance.”
The results validate a recent Dutch study that also showed coffee-drinkers lowered their risk of diabetes.