Drinking tea and coffee may reduce the risk of developing type 2 diabetes, a 2022 study found. Men that drank a beverage enriched in polyphenols present in tea and coffee had lower blood glucose levels and improved insulin sensitivity than those who drank a placebo.

Eleven healthy men drank a beverage that contained either polyphenols from tea (catechins) and coffee (chlorogenic acids) or a placebo every day for three weeks. Both beverages provided 119 milligrams of caffeine – a little more than the amount present in one cup of coffee. At the end of the three weeks, they ate a high-fat, high-carbohydrate meal, and then researchers measured their blood glucose, insulin, and other metabolic markers.

The researchers found that consuming the catechin- and chlorogenic-rich beverage reduced the men’s blood glucose levels when consumed with a high-fat or high-carbohydrate meal. Their insulin sensitivity and levels of hormones involved in glucose metabolism increased, as well.

Catechins are polyphenolic compounds found in tea, cocoa, and berries. Evidence suggests that catechins ameliorate symptoms associated with diabetes. Chlorogenic acids are polyphenolic compounds found in coffee, apples, and berries. Evidence suggests that chlorogenic acids reduce inflammation, a key player in the pathophysiology of diabetes.

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• Learn more about polyphenols in our overview article.