Study details

For the study, researchers from the Friedman School of Nutrition Science and Policy at Tufts University analyzed data from nine cycles of the National Health and Nutrition Examination Survey, from 1999 to 2018. The researchers looked at the self-reported coffee-drinking habits of more than 46,000 U.S. adults and tracked their mortality data through the national death index.  

Coffee consumption was categorized by type — caffeinated or decaffeinated — and by how much added sugar and saturated fat, such as milk or cream, was included. Mortality outcomes were analyzed across all causes, including cardiovascular disease and cancer.

"Coffee is among the most-consumed beverages in the world," said Fang Fang Zhang, senior author of the study and the Neely Family Professor at the Friedman School. "[W]ith nearly half of American adults reporting drinking at least one cup per day, it's important for us to know what it might mean for health."

The study found that drinking one to three cups of caffeinated coffee per day was consistently associated with a reduced risk of dying from any cause.

In addition, people who drank black coffee — or coffee with only "low" levels of sugar and saturated fat — had a 14% lower risk of all-cause mortality compared to those who didn't drink coffee at all.

More specifically, drinking one cup of coffee per day was linked to a 16% lower risk of death, while two to three cups was linked to a 17% lowered risk. But these benefits plateaued or even weakened beyond three cups a day, especially for cardiovascular outcomes. 

Commentary

What makes black coffee potentially life-extending, experts say, is a combination of several biologically active, naturally occurring compounds in coffee beans.

"The health benefits of coffee likely originate from the bioactive compounds in coffee beans such as caffeine and chlorogenic acid," Zhang said. These compounds may boost metabolism, reduce inflammation, and support gut health.

"Moderate coffee intake has been shown to improve blood vessel function," said registered dietitian Scott Keatley of Keatley Medical Nutrition Therapy. "Essentially, black coffee acts almost like a mild drug — stimulating, anti-inflammatory, and metabolically supportive."

Drinking coffee itself may be helpful, but what you put in it matters just as much. "Too much sugar increases inflammation in the body and insulin resistance, too," Keatley said. "There's also a behavioral angle: Individuals who consume black coffee may, on average, have other health-conscious habits, they tend to smoke less, move more, and consume fewer ultra-processed foods."

Family physician David Cutler from Providence Saint John's Health Center, emphasized that while we may not know the exact mechanisms at play, the takeaway, simply put, is, "black coffee is safe to drink and there may, in fact, be some significant health benefits from it."

Keatley added that black coffee is associated with a reduced risk of several chronic diseases, including type 2 diabetes, Parkinson's, and some cancers. "[Black coffee] also appears to support cognitive function over time and may reduce the risk of depression," Keatley said.

If you're reaching for coffee as part of a healthy lifestyle, how you take it matters, experts say. Black coffee, or even coffee with minimal sugar and cream, may offer the greatest benefit.

"Coffee, when taken plain, supports metabolic health without adding dietary burden," Keatley said. "It's one of the rare dietary tools that can act on multiple systems at once, brain, gut, heart, without requiring a prescription."