Moderate coffee intake may lower risk of diabetes, heart disease, stroke

Three cups of coffee a day, or 200 to 300 mg of caffeine, was the sweet spot in a large study that tied moderate intake to a lower risk of type 2 diabetes, coronary heart disease and stroke. For daily drinkers, the message is blunt: the benefit sat in the middle, not at the high end.

The study, published Sept. 17, 2024 in The Journal of Clinical Endocrinology & Metabolism, used UK Biobank data and followed participants for about 12 years. It looked at 188,091 people for coffee and tea analyses and 172,315 for caffeine analysis, and all were free of cardiometabolic disease at baseline. In this study, cardiometabolic multimorbidity meant having at least two of three conditions: type 2 diabetes, coronary heart disease and stroke.

The numbers lined up around moderation. Moderate coffee intake had a hazard ratio of 0.519 versus nonconsumers, while moderate caffeine intake came in at 0.593 compared with nonconsumers or people consuming under 100 mg of caffeine daily. That works out to a 48.1% lower risk with moderate coffee and a 40.7% lower risk with moderate caffeine. Chaofu Ke of Soochow University in Suzhou, China, said consuming three cups of coffee or 200 to 300 mg of caffeine per day might help reduce the risk of developing cardiometabolic multimorbidity in healthy people.

The biology behind the pattern was not random noise. Researchers identified 80 to 97 metabolites linked to coffee, tea or caffeine intake and incident cardiometabolic multimorbidity, including lipid components within very low-density lipoprotein, histidine and glycoprotein acetyls. That adds another layer to earlier observational work suggesting coffee and tea may be linked to lower risks of individual cardiometabolic diseases.

Harvard Health put the practical takeaway in plain terms: 200 to 300 mg of caffeinated tea or coffee per day was linked to lower risk, and there was no reason, from a health standpoint, to switch from coffee to tea. The real takeaway for coffee drinkers is the one the study keeps coming back to, the upside is strongest when the cup count stays moderate.