Drinking a cup or two of black coffee daily could lower risk of death by 14 per cent, but adding milk or sugar could diminish the benefits, according to a new study.

The same link was not observed for coffee with high amounts of added sugar and saturated fat, researchers said.

"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," Fang Fang Zhang, from Tufts University in the US, and senior author of the study published in The Journal of Nutrition, said.