Good news for coffee lovers: A new study suggests drinking a cup—or several—each day could be linked to long-term health benefits.
The study, presented on Monday at the annual meeting of the American Society for Nutrition in Orlando, found that roughly 3,700 women who met researchers’ criteria for “healthy aging” typically consumed an average of 315 mg of caffeine per day when they were between the ages of 45 and 60, mostly from drinking coffee. And for the women in that group of “healthy agers,” each extra cup of coffee per day was associated with a 2-5% higher chance of faring well as they aged, up to five small cups per day.
“We found that women who consumed moderate amounts of caffeinated coffee in midlife were more likely to age in good health,” Sara Mahdavi, an adjunct professor in the University of Toronto’s department of nutritional sciences who led the research, told TIME in an email. “That’s not to say coffee is a cure-all, but for those who already drink and tolerate it well, it appears to be a positive part of a healthy lifestyle.”
The study, which has not yet been peer reviewed or published, followed 47,513 middle-aged female nurses under the age of 60 for three decades, starting in 1986. Researchers asked the women questions about their diet, such as how much coffee, tea, cola, and decaffeinated coffee they drank.
They then analyzed how many of those women met their requirements for “healthy aging,” which they defined as living to age 70 or older; maintaining good physical, cognitive, and mental health; and being free from 11 major chronic diseases, including heart disease, stroke, Type 2 diabetes, and cancer, among others. In 2016, researchers determined that 3,706 of the women met their criteria, and found the link to their caffeine intake.
The study didn’t find any significant link between drinking decaf coffee or tea and the likelihood of healthy aging. And for soda, it found an opposite correlation: Each additional small glass was associated with a 20-26% lower likelihood of healthy aging.
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Mahdavi said coffee is “uniquely rich in bioactive compounds,” containing ingredients like chlorogenic acids and small amounts of micronutrients that may influence factors critical to how we age, such as inflammation, blood vessel function, and glucose metabolism. Tea and decaf coffee may also contain some of those ingredients, but in different concentrations.
“Cola, on the other hand, lacks these altogether and contains other ingredients that may work against healthy aging,” Mahdavi said. “Our findings suggest that the observed benefits are specific to caffeinated coffee, not caffeine itself, and not to all caffeinated beverages.”
While Mahdavi said the findings are significant, she also advised caution. The study found an association between coffee and healthy aging, but not a cause-and-effect relationship. Researchers pointed out that, generally, drinking up to two cups of coffee a day should be safe and could be beneficial for people, but drinking more than that may not be healthy for some, though it may offer additional benefits for others. And coffee can’t replace other factors that affect aging, Mahdavi said.
“Women who aged best were also more likely to eat well, exercise regularly, and avoid smoking—those behaviors matter much more,” Mahdavi said. “Also, more isn’t necessarily better. The clearest benefits were seen with moderate coffee intake—about 2 to 4 cups a day. People who are sensitive to caffeine or have medical reasons to avoid it should still do so.”
“But for women in midlife who already drink coffee and feel well doing so, these findings are reassuring,” she said.
