Drinking coffee may do more than provide a daily energy boost. According to a large review study, people who consume three to four cups of coffee per day are more likely to experience positive health outcomes than those who avoid coffee altogether.
The analysis brings together findings from more than 200 previous studies examining coffee’s health effects. Overall, the research links regular coffee consumption to a reduced risk of several major conditions, including heart disease, type 2 diabetes, liver disease, dementia, and certain forms of cancer.
Researchers suggest that three to four cups per day appears to be the optimal range for potential health benefits. However, they caution that this guidance may not apply to everyone, particularly pregnant women or individuals at elevated risk of bone fractures.
To better understand coffee’s impact on health, scientists at the University of Southampton reviewed 201 observational studies and 17 clinical trials conducted worldwide.
“Coffee drinking seems harmless within the usual pattern of consumption,”
— The researchers conclude in the study published in the BMJ.
The review found consistent associations between coffee consumption and a lower risk of premature death from several diseases. The most pronounced benefits were observed among individuals drinking around three cups per day compared with non-coffee drinkers.
Consuming more than three cups did not appear to increase health risks, but it also did not correlate with significantly greater benefits.
Co-author Professor Paul Roderick noted in comments to the BBC that the findings show correlation rather than proven causation.
“Factors such as age, whether people smoked or not and how much exercise they took could all have had an effect,”
The review also associated coffee intake with lower risks of several cancers, including prostate, skin, and liver cancer, as well as reduced incidence of type 2 diabetes, gallstones, and gout.
Because much of the underlying evidence comes from observational research, the authors emphasize that firm cause-and-effect conclusions cannot yet be drawn. Lifestyle factors linked to coffee consumption may partly explain the observed health advantages.
Reference:
Robin Poole et al. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ 2017; 359:j5024. Published 22 November 2017.