In fact, in numerous studies conducted throughout the world, consuming four or five eight-ounce cups of coffee (or about 400 milligrams of caffeine) a day has been associated with reduced death rates. In a study of more than 200,000 participants followed for up to 30 years, those who drank three to five cups of coffee a day, with or without caffeine, were 15 percent less likely to die early from all causes than were people who shunned coffee. Perhaps most dramatic was a 50 percent reduction in the risk of suicide among both men and women who were moderate coffee drinkers, perhaps by boosting production of brain chemicals that have antidepressant effects. As a report published last summer by a research team at the Harvard School of Public Health concluded, although current evidence may not warrant recommending coffee or caffeine to prevent disease, for most people drinking coffee in moderation “can be part of a healthy lifestyle.”