Coffee health benefits may fade with sugar and fat

Drinking coffee may help you live longer — but only if it’s black. 

A new long-term study analyzing the coffee habits of more than 46,000 U.S. adults found that coffee drinkers had a lower risk of dying from any cause, but only when the coffee was consumed without significant amounts of added sugar or saturated fat.

Researchers from Tufts University published the findings in the journal Nutritional Epidemiology, drawing on two decades of data from the National Health and Nutrition Examination Survey (NHANES), which was linked to National Death Index records. 

The study tracked adults 20 years and older from 1999 to 2018 and examined not only how much coffee they drank but also what they put in it.

Participants who drank 1 to 3 cups of coffee per day saw up to a 17% lower risk of all-cause mortality compared to non-coffee drinkers. But those benefits disappeared for people who regularly added cream, sweeteners, or other high-fat, high-sugar ingredients to their coffee.

Over the median 9 to 11-year follow-up period, researchers documented more than 7,000 deaths among participants, including 1,176 from cancer and 1,089 from cardiovascular disease. When broken down further, the data showed that drinking black coffee or coffee with minimal sugar and saturated fat was associated with a 14% lower risk of death.

“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 Dr. Fang Fang Zhang, senior author of the study and a professor at Tufts University.

The study defined “low” sugar as less than 2.5 grams and “low” saturated fat as less than 1 gram per 8-ounce cup. Most coffee drinkers in the study exceeded those thresholds. On average, each cup contained 3.24 grams of added sugar and 0.52 grams of saturated fat.

Researchers employed Cox proportional hazards models to investigate the relationship between coffee consumption and mortality. The strongest associations were observed among those drinking between 1 and 3 cups of coffee daily — primarily when consumed black.

The study’s authors stated that the findings support previous research indicating that compounds naturally found in coffee, such as polyphenols and chlorogenic acids, may offer antioxidant and anti-inflammatory benefits. However, they cautioned that these benefits may be negated by the addition of sugary syrups and high-fat creamers, which contribute empty calories and may increase health risks over time.

Also, a separate Harvard study tracking nearly 48,000 women over three decades found that those who drank at least one cup of coffee daily were more likely to reach age 70 in good health—free of major chronic diseases and cognitive decline—compared to non-coffee drinkers. Researchers concluded that regular coffee consumption was associated with what they termed “healthy aging” in women.

“Given how common coffee drinking is in the U.S., it’s important for people to know that how they take their coffee can make a difference,” Zhang said.