Boston, MA - People who drink about three to five cups of coffee a day may be less likely to die prematurely from some illnesses than those who don't drink or drink less coffee, according to a new study by Harvard T.H. Chan School of Public Health researchers and colleagues. Drinkers of both caffeinated and decaffeinated coffee saw benefits, including a lower risk of death from cardiovascular disease, neurological diseases, type 2 diabetes, and suicide.
"Bioactive compounds in coffee reduce insulin resistance and systematic inflammation," said first author Ming Ding, a doctoral student in the Department of Nutrition. "That could explain some of our findings. However, more studies are needed to investigate the biological mechanisms producing these effects."
The study will appear online in Circulation on November 16, 2015.
Researchers analyzed health data gathered from participants in three large ongoing studies: 74,890 women in the Nurses' Health Study; 93,054 women in the Nurses' Health Study 2; and 40,557 men in the Health Professionals Follow-up Study. Coffee drinking was assessed using validated food questionnaires every four years over about 30 years. During the study period, 19,524 women and 12,432 men died from a range of causes.
In the whole study population, moderate coffee consumption was associated with reduced risk of death from cardiovascular disease, diabetes, neurological diseases such as Parkinson's disease, and suicide. Coffee consumption was not associated with cancer deaths. The analyses took into consideration potential confounding factors such as smoking, body mass index, physical activity, alcohol consumption, and other dietary factors.
"This study provides further evidence that moderate consumption of coffee may confer health benefits in terms of reducing premature death due to several diseases," said senior author Frank Hu, professor of nutrition and epidemiology. "These data support the 2015 Dietary Guidelines Advisory Report that concluded that 'moderate coffee consumption can be incorporated into a healthy dietary pattern.'"
Other Harvard Chan School authors include Ambika Satija, Shilpa Bhupathiraju, Yang Hu, Qi Sun, Jiali Han, Esther Lopez-Garcia, Walter Willett, and Rob van Dam.
This study was supported by National Institutes of Health research grants UM1 CA186107, UM1 CA176726, UM1 CA167552, P01 CA87969, P01 CA055075, R01 HL034594, HL088521, HL35464, and HL60712.
"Association of Coffee Consumption with Total and Cause-specific Mortality in Three Large Prospective Cohorts," Ming Ding, Ambika Satija, Shilpa N. Bhupathiraju, Yang Hu, Qi Sun, Walter Willett, Rob M. van Dam, Frank B. Hu, Circulation, online November 16, 2015.
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Harvard T.H. Chan School of Public Health brings together dedicated experts from many disciplines to educate new generations of global health leaders and produce powerful ideas that improve the lives and health of people everywhere. As a community of leading scientists, educators, and students, we work together to take innovative ideas from the laboratory to people's lives--not only making scientific breakthroughs, but also working to change individual behaviors, public policies, and health care practices. Each year, more than 400 faculty members at Harvard Chan School teach 1,000-plus full-time students from around the world and train thousands more through online and executive education courses. Founded in 1913 as the Harvard-MIT School of Health Officers, the School is recognized as America's oldest professional training program in public health.