People who drink coffee appear to live longer, two new studies published in the U.S. journal Annals of Internal Medicine said Monday, providing further confirmation on the health benefits of coffee consumption.
The first study, conducted in 10 European countries and the largest ever of its kind, found that compared to non-coffee drinkers, those who consume the most coffee have a significantly lower risk for death.
The second study found that higher coffee consumption was associated with lower risk for death in whites and also in non-white populations and that the mortality benefit was the same for caffeinated and decaffeinated coffee.
This finding of the second study, done by researchers at the University of Southern California, is important because different races have different lifestyles and disease risks.
"Recommending coffee intake to reduce mortality or prevent chronic disease would be premature," an accompanying editorial of the journal wrote.
"However, it is increasingly evident that moderate coffee intake up to three to five cups per day or caffeine intake up to 400 mg/d is not associated with adverse health effects in adults and can be incorporated into a healthy diet."
In the first study, researchers from the International Agency for Research on Cancer and Imperial College London used data from the European Prospective Investigation into Cancer and Nutrition, a large multinational cohort study of more than 520,000 men and women from 10 European countries with an average follow-up of 16 years, to compare all-cause and cause-specific mortality in coffee drinkers compared to non-coffee drinkers.
They found that participants who reported drinking three or more cups of coffee per day seemed to receive the most benefit in terms of lowering the rate of death. This was particularly true for diseases of the digestive tract, but also for circulatory diseases.
In the second study, investigators at the University of Southern California sought to determine how coffee consumption affected health across multiple races by using data from the Multiethnic Cohort study, which followed more than 185,000 African Americans, Native Americans, Hawaiians, Japanese Americans, Latinos, and whites for an average of 16 years.
They found that drinking coffee was associated with a lower risk due to heart disease, cancer, stroke, diabetes, and respiratory and kidney disease for African-Americans, Japanese-Americans, Latinos and whites.
People who consumed a cup of coffee a day were 12 percent less likely to die compared to those who didn't drink coffee. This association was even stronger for those who drank two to three cups a day -- 18 percent reduced chance of death.
Since coffee drinking among non-white communities previously had little research, this study substantially increases the generalizability of previous findings across the racial and ethnic spectrum, the researchers said.
In addition, lower mortality was present regardless of whether people drank regular or decaffeinated coffee, suggesting the association is not tied to caffeine.
According to the accompanying editorial, a protective effect of coffee is biologically plausible because polyphenols and other bioactive compounds in it have antioxidant properties, which are linked to reduced insulin resistance, inflammation, and biomarkers of liver function.
Coffee is one of the world's most commonly consumed beverages, with an estimated 2.25 billion cups drank around the world each day. Because of its ubiquitous consumption, understanding coffee's health effects is important.