A new study has found that drinking black coffee may significantly lower the risk of death — but those benefits may disappear if you load your cup with cream and sugar.
According to a study published in The Journal of Nutrition by researchers at Tufts University’s Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy, consuming black coffee or coffee with minimal additives is linked to a reduced risk of death from all causes, including cardiovascular disease.
“Coffee is among the most-consumed beverages in the world,” said Dr. Fang Fang Zhang, senior author of the study and Neely Family Professor at the Friedman School. “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.”
The researchers analyzed data from more than 46,000 U.S. adults using nearly two decades of dietary recall records from the National Health and Nutrition Examination Survey (NHANES), spanning from 1999 to 2018. The study assessed coffee consumption — both caffeinated and decaffeinated — as well as the quantity of added sugars and saturated fats.
The results showed that participants who drank 1–2 cups of black or lightly sweetened coffee per day had a 14% lower risk of death compared to non-coffee drinkers. Those who consumed 2–3 cups daily saw a 17% reduction. However, the benefits plateaued with higher intake, and excessive consumption appeared to lessen any cardiovascular advantage.
“Few studies have examined how coffee additives could impact the link between coffee consumption and mortality risk,” said lead author Bingjie Zhou, a recent Ph.D. graduate in nutrition epidemiology and data science. “Our study is among the first to quantify how much sweetener and saturated fat are being added.”
In the study, coffee was considered “lightly sweetened” if it contained less than 2.5 grams of sugar per cup — roughly half a teaspoon — and less than 1 gram of saturated fat, which equates to one tablespoon of light cream or five tablespoons of 2% milk. Coffee with additive levels above those thresholds did not show statistically significant reductions in mortality risk.
Interestingly, decaffeinated coffee was not associated with the same longevity benefits. Researchers suggested this might be due to the smaller number of decaf drinkers in the sample size.
The findings reinforce existing guidance from the Dietary Guidelines for Americans, which recommend limiting added sugars and saturated fats in daily consumption.
However, the study’s authors acknowledged some limitations, particularly the reliance on 24-hour dietary recalls, which can vary daily and may be subject to reporting inaccuracies.
“Our research helps fill a gap in the conversation about coffee and health,” Zhou concluded. “It’s not just what’s in the coffee bean — it’s also what you’re putting in your cup.”
