LONDON – Against the backdrop of years of conflicting information about the health effects of coffee, two new studies published this week have concluded that greater consumption of the beverage could lead to a longer life.
One of the studies looked at more than 520,000 people across 10 European countries, making it the largest study ever on coffee and longevity, and found that drinking coffee could significantly increase life expectancy.
The other study focused on non-white populations. After surveying over 185,000 African-Americans, Native Americans, Hawaiians, Japanese-Americans, Latinos and whites, the researchers concluded that coffee increased longevity regardless of race.
According to the study, people who drank two to four cups of coffee a day had an 18 percent lower risk of mortality than those who did not.
These findings are consistent with earlier studies that had surveyed majority white populations, said Veronica Wendy Setiawan, associate professor of preventative medicine at USC’s Keck School of Medicine, who led the study on non-white populations.
“Given these very diverse populations, all these people have different lifestyles. They have very different dietary habits and different susceptibilities — and we still find similar patterns,” she said.
The research indicated that mortality was inversely related to coffee consumption for heart disease, stroke, cancer, respiratory disease, diabetes and kidney disease.
Meanwhile, the study on European countries found an inverse association between coffee and liver disease, suicide in men, cancer in women, digestive diseases and circulatory diseases. People who drank three or more cups a day had a lower risk for all-cause death than people who did not, moreover.
“We looked at multiple countries across Europe, where the way the population drinks coffee and prepares coffee is quite different,” said Marc Gunter, reader in cancer epidemiology and prevention at Imperial College’s School of Public Health in London, who co-authored the European study.
“The fact that we saw the same relationships in different countries is kind of the implication that it’s something about coffee rather than its something about the way that coffee is prepared or the way it’s drunk,” he said.
Gunter added that coffee is a complex mixture of compounds, some of which have been shown to have biological effects. Studies have shown that certain compounds have neuroprotective and anti-inflammatory properties that can help reduce risk for illnesses like Parkinson’s disease.
Coffee drinkers in the European study tended to have lower levels of inflammation, healthier lipid profiles and better glucose control.
Gunter nevertheless noted that it was difficult to exclude the possibility that coffee drinkers were simply healthier to begin with.
People who avoid coffee may do so because they have health problems. Their higher mortality rate could be a result of them being less healthy at the outset.
Both studies were published in the Annals of Internal Medicine.