New Issue: Science’s Impossible Questions. Read Now

Coffee Consumption Linked to Lower Diabetes Risk

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


For many people, a cup of coffee signals the start of the day. For those who continue to drink the beverage all day long, new findings support their habit. According to a report published in the current issue of the journal Annals of Internal Medicine, heavy java drinkers have a lower risk of developing type 2 diabetes, a disease that currently afflicts about 15 million Americans.

Sufferers of type 2 diabetes, which is sometimes referred to as adult-onset diabetes because it is more common in older patients, do not utilize insulin properly to metabolize food. In addition to age, risk factors for the disease include being overweight and physically inactive. In 2000, a Dutch study suggested that once other risks are accounted for, coffee drinkers may be less likely to develop type 2 diabetes than non-coffee drinkers are, but it did not differentiate between caffeinated and non-caffeinated varieties. In the new work, a group of researchers from Harvard University and Brigham and Women's Hospital in Boston followed some 126,000 people for more than a dozen years. Every few years the participants answered detailed questionnaires that included questions about their java habits. The scientists determined that men who drank more than six cups of caffeinated joe each day had a risk of developing type 2 diabetes that was half that of their peers who did not drink caffeinated coffee. Among women, the risk was 30 percent lower for regular coffee drinkers compared to non-drinkers. The effects for decaf coffee lovers were smaller: a 25 percent risk reduction for men and a 15 percent reduction for women as compared to non-drinkers.

"This is good news for coffee drinkers, however it doesn't mean everyone should run out for a latt¿," cautions study co-author Frank B. Hu of the Harvard School of Public Health. "We still don't know exactly why coffee is beneficial for diabetes, and more research is clearly needed." For one, caffeine has been shown to raise blood sugar levels in the short-term; the authors note, however, that its long-term effects are not yet well understood. The team suggests that other ingredients in a cup of joe, including antioxidants and magnesium, could contribute to the beneficial effects of the beverage against diabetes.

Subscribe to Support Independent Journalism

Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.

When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.

Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber

Thank you,

Jeanna Bryner, Editor in Chief, Scientific American

Subscribe