“When I was in medical school, we were taught that coffee was bad,” says Peter R. Martin, M.D., director of Vanderbilt University’s Institute for Coffee Studies. “But that was because early studies in the 1960s and 1970s were not well done, not taking into effect other lifestyle factors, such as that people who drank coffee also tended to smoke. And they developed health problems.” (Researchers have now realized that in those early studies, coffee-drinking smokers tended to under-report how much they smoked.)
Today, however, epidemiological studies are done more carefully, tracking various factors affecting health and illness in large groups for many years or decades. Most, say leading researchers, reach the same conclusion: For those not prone to its effect on sleep problems (decaf solves that) or indigestion, and not worried that it can slightly raise “bad” cholesterol, coffee is healthy and may even help prevent many age-related conditions.
“Coffee is most famous for being the best source of caffeine—there’s three times as much in a cup of coffee compared to an equal amount of cola—and despite its bad reputation, caffeine has some health benefits. But coffee is a very complex substance with as many as 2,000 different chemical components, including many powerful antioxidants and phytochemicals,” notes James Coughlin, a food and chemical toxicologist who has studied coffee’s health effects for more than three decades and has personally conducted or analyzed data from some 10,000 studies.
What’s more, roasting coffee beans causes a chemical reaction that makes some of these disease-fighting antioxidants even more powerful, adds Coughlin, past president of the Association for Science and Information on Coffee, a Paris-based organization of scientists who conduct coffee-related research and are funded in part by the coffee industry. This may explain why, measure for measure, coffee has been documented as the richest source of antioxidants in the American diet.
Beyond caffeine, benefits of the bean
On its own, caffeine reacts with certain brain receptors—one explanation why studies have shown it protects against Alzheimer’s and Parkinson’s, boosts mood and lowers suicide risk, and reduces pain. But an additional brain-boosting benefit comes from coffee’s abundance of chlorogenic acids, a family of antioxidants that also protect the brain and other body systems, adds Martin. “Chlorogenic acids improve the capacity of the body to metabolize sugar and glucose, which is perhaps the reason why it may be protective against type 2 diabetes and liver disease.”
In one notable study that analyzed data on 126,000 people over a period of 18 years, Harvard researchers found that, all else being equal, those drinking one to three cups of caffeinated coffee each day were slightly less likely than nondrinkers to develop type 2 diabetes. But among those drinking six or more cups daily, men’s risk was slashed by 54 percent and women’s by 30 percent compared with nondrinkers. Since then, other studies have found that regularly drinking decaf also lowers the risk of diabetes.