Study Shows Drinking Black Coffee Reduces Mortality Risk by 17%

New Delhi: A new study from the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University has found that drinking 1–2 cups of caffeinated coffee per day is associated with a lower risk of death from all causes—especially cardiovascular disease. However, the potential health benefits diminish when coffee is heavily sweetened or contains high amounts of saturated fat.

Published in The Journal of Nutrition, the study analyzed data from nine consecutive cycles of the National Health and Nutrition Examination Survey (NHANES), spanning from 1999 to 2018. The researchers examined information from a nationally representative group of 46,000 U.S. adults aged 20 and older who provided valid 24-hour dietary recalls. These data were linked to mortality records from the National Death Index.

“Coffee is among the most-consumed beverages in the world, and with 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,” said Fang Fang Zhang, senior author of the study and Neely Family Professor at the Friedman School.

Key Findings:

1 cup of coffee per day was associated with a 16% lower risk of death from all causes.

2–3 cups per day were linked to a 17% lower risk.

Drinking more than 3 cups daily did not provide additional benefit and showed a weaker link to reduced cardiovascular mortality.

The benefits were specifically tied to black coffee or coffee with low amounts of added sugar and saturated fat. The study defined “low” as:

Less than 2.5 grams of sugar per 8-ounce cup (about half a teaspoon)

Less than 1 gram of saturated fat per 8-ounce cup (equal to 5 tablespoons of 2% milk or 1 tablespoon of cream)

“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,” Zhang noted.

Unlike many earlier studies, this research is among the first to quantify the amount of sugar and fat added to coffee and examine how those additions affect long-term health outcomes.

“Few studies have examined how coffee additives could impact the link between coffee consumption and mortality risk, and our study is among the first to quantify how much sweetener and saturated fat are being added,” said Bingjie Zhou, the study’s lead author and a recent Ph.D. graduate from the Friedman School.

The findings align with the Dietary Guidelines for Americans, which recommend limiting both added sugars and saturated fat to support long-term health.

Researchers acknowledged some limitations, including the self-reported nature of dietary recalls, which can vary day to day and may contain inaccuracies. Additionally, decaffeinated coffee did not show a significant association with reduced mortality risk, possibly due to lower consumption rates among study participants.

Other authors of the study include Yongyi Pan, Lu Wang, and Mengyuan Ruan, all affiliated with the Friedman School.