Even a single cup a day seemed to lower risk a little: 6 percent in men and 5 percent in women. The strongest effect was in women who had four or five cups a day — a 16 percent lower risk of death.

The study of 400,000 people is the largest ever done on the issue, and the results should reassure any coffee lovers who think it’s a guilty pleasure that may do harm.

The study was done by the National Institutes of Health and AARP. The results are published in Thursday’s New England Journal of Medicine.