If you like your coffee black, your morning habit may be doing more than waking you up — it could be linked to a longer life.
A new study from researchers at Tufts University found that drinking one to two cups of caffeinated coffee each day was associated with a 14% lower risk of death from all causes, including cardiovascular disease. But there’s a catch: The benefit didn’t hold up when people loaded their coffee with sugar or saturated fat.
“The health benefits of coffee might be attributable to its bioactive compounds, but our results suggest that the addition of sugar and saturated fat may reduce the mortality benefits,” said senior author Fang Fang Zhang, the Neely Family Professor at Tufts’ Friedman School of Nutrition Science and Policy.
The study, published in The Journal of Nutrition, analyzed national survey data from more than 46,000 U.S. adults over a nearly 20-year span. Researchers looked at coffee habits — including how much sweetener, cream or milk people added — and linked them with long-term mortality data from the National Death Index.
Among the findings:
Drinking one or two cups of black or lightly sweetened coffee daily was associated with a 14–17% lower risk of death.
Drinking more than three cups a day didn’t add additional benefit.
High amounts of sugar or cream erased the observed protective effects.
No link was found between coffee and cancer mortality.
First author Bingjie Zhou noted this is one of the first large-scale studies to quantify how added ingredients impact coffee’s potential health effects.
“Our results align with the Dietary Guidelines for Americans, which recommend limiting added sugar and saturated fat,” she said.
The research was funded by the National Institutes of Health’s National Institute on Minority Health and Health Disparities. The authors emphasized that the study’s conclusions reflect their own analysis and not official positions of the NIH.