Study Finds Coffee Compounds May Reduce Risk of Type 2 Diabetes

A new study published in the International Journal of Molecular Sciences suggests that drinking black coffee—whether caffeinated or decaffeinated—may help lower the risk of developing type 2 diabetes. The findings point to naturally occurring polyphenols in coffee, not caffeine, as the key compounds offering potential protection.

Researchers from universities in the Republic of Korea analyzed data from 149 scientific publications to evaluate coffee’s impact on metabolic factors linked to type 2 diabetes. The focus was on five hydroxycinnamic acids found in coffee and their influence on the intestines, pancreas, liver, muscles, and tissue.

Their analysis revealed that consuming 3 to 5 cups of black coffee daily may:

• Regulate blood sugar levels

• Reduce inflammation

• Improve insulin sensitivity

• Enhance antioxidant activity

• Support healthier glucose metabolism

These benefits were observed regardless of whether the coffee contained caffeine. According to the study, regular coffee drinkers may experience a 20–30% lower risk of developing type 2 diabetes.

The researchers concluded that polyphenols—particularly chlorogenic acid and related hydroxycinnamic acid derivatives—could play a preventive role in diabetes management. However, they also emphasized the need for further clinical studies.

Dr. Zhaoping Li, professor of medicine and chief of clinical nutrition at UCLA, who was not involved in the study, endorsed the findings. “Drinking coffee provides natural benefits. You can make coffee part of your healthy lifestyle,” she said.

Dr. Marilyn Tan, a clinical associate professor of medicine at Stanford University, noted that while the findings are promising, some of the underlying data came from lab studies. She also cautioned that observational studies may not fully account for other health and lifestyle factors among coffee drinkers.

Still, Tan acknowledged the significance of the results: “A 20–30% risk reduction is very large and meaningful. The fact that both caffeinated and decaffeinated coffee showed similar effects suggests the benefits are due to other bioactive components in coffee, not caffeine.”

Dr. Li added that coffee beans contain more than 200 compounds, many of which have health-promoting properties—some similar to those found in medicinal spices. “The health benefits of black coffee seem to be obvious,” she said.

Previous studies have linked regular coffee consumption to reduced risks of cardiovascular disease, improved brain health, lower depression rates, and protection against certain liver conditions.

Experts recommend drinking coffee without added sugar or cream and avoiding pairing it with unhealthy foods to maximize its health benefits.