A new study found that drinking several cups of coffee in a day cuts down the risk of suicide among men and women by 50 percent.
Coffee lovers who apparently drink two to four cups daily are found to be at reduced risk of suicide, as compared to those who drink decaffeinated coffee or little to no coffee.
Researchers at the Harvard School of Public Health (HSPH) reviewed data on 43,599 men enrolled in the Health Professionals Follow-Up Study (HPFS) (1988-2008), 73,820 women in the Nurses' Health Study (NHS) (1992-2008), and 91,005 women in the Nurses' Health Study II (NHSII) (1993-2007).
"Unlike previous investigations, we were able to assess association of consumption of caffeinated and non-caffeinated beverages, and we identify caffeine as the most likely candidate of any putative protective effect of coffee," lead researcher Michel Lucas, research fellow in the Department of Nutrition at HSPH, told the Harvard Gazette.
Apparently, caffeine boosts certain neurotransmitters (including serotonin and dopamine) in the brain that makes coffee act like a mild antidepressant. Hence, the lowered risk of depression found in previous epidemiological studies is explained, the researchers said.
Every four years, those who enrolled for the study were given questionnaires to assess their caffeine, coffee, and decaffeinated coffee intake. The study calculated their caffeine consumption from coffee, tea, caffeinated soft drinks, and chocolate.
However, the major caffeine source was coffee throughout the study - 80 percent for NHS, 71 percent for NHS II, and 79 percent for HPFS. Among the enrolled were 277 deaths from suicide.
However, the researchers did not recommend an increase in caffeine intake for the depressed as 'most individuals adjust their caffeine intake to an optimal level for them and an increase could result in unpleasant side effects'.
"Overall, our results suggest that there is little further benefit for consumption above two to three cups/day or 400 mg of caffeine/day," the authors said in the study.
Moreover, the study did not address the impact of six or more cups of coffee per day.