It is said that the French author Honoré de Balzac drank up to 50 cups of coffee every day to fuel his grueling writing binges in the middle of the night. While today's coffee addicts can undoubtedly sympathize with Balzac's insane coffee consumption as a productivity booster, according to two new major studies, there may be another big benefit to binging on bean: a longer life.
The first study, led by USC associate professor of preventative medicine Wendy Setiawan, found that people who drink at least one cup of coffee per day are about 12 percent less likely to die than non-coffee drinkers. The finding is based on 16 years' worth of data collected from 185,000 Americans over the age of 45. For those who drank two or three cups a day, they were 18 percent less likely to die. As detailed in Annals of Internal Medicine, whether the coffee was caffeinated did not matter.
Although Setiawan's study wasn't the first to link coffee consumption with longevity, it is unique in the ethnic diversity of its data. Prior to the USC research, most studies looking at coffee and health focused specifically on white populations. In Setiawan's research, however, whites only accounted for 25 percent of the research cohort, while Japanese-Americans accounted for 29 percent, Latinos accounted for 22 percent and African-Americans accounted for 17 percent.
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"Until now, there was very little data about coffee and non-Caucasians," Setiawan says. "But findings in Caucasians may not be really applicable to other groups. So with this study we had a multi-ethnic cohort and showed that coffee lowered the rates of death in non-Caucasian populations, too."
A second study released today in Annals of Internal Medicine from Imperial College London further boosts Setiawan's observations. This study, which included data from over 500,000 people over the age of 35 in ten European countries, also noted that increased coffee consumption was correlated with a lower risk of death from all causes, but particularly cardiovascular disease. According to the researchers, drinking three or more cups of coffee per day was correlated with the lowest risk of death in the cohort.
In addition, the Imperial London researchers also conducted a sub-study on 14,000 individuals that looked at metabolic biomarkers, or quantifiable biological parameters used to measure health. Overall, they found that coffee drinkers tend to have healthier livers and better glucose control than those who abstain from the bean.
While these results may come as a breath of fresh air for the coffee enthusiasts out there, it's important to recognize that these are observational studies, not clinical research. In other words, these research groups have seen statistically significant correlations between coffee consumption and longevity. In order to establish a causal mechanisms, researchers will need to do more clinical research to see how coffee affects certain areas of the body, such as the liver.
Still, these studies add some much needed statistical legitimacy to the study of coffee and health, which is plagued by contradictory research. For example, in 1991 the World Health Organization had labeled coffee as a "possible carcinogen" based on its apparent links with cancer in the urinary bladder. This label stood until 2016, when the WHO reversed its stance and acknowledged that coffee can actually reduce the likelihood of getting certain types of cancer based on new research.
"For people who studied coffee in the past, these studies may have been small or not properly analyzed, leading to conflicting results about the effect of coffee on health," Setiawan says. "I would love to see somebody doing clinical trials with randomized populations and controls that looked at the effect of coffee on something like liver function because in an observational study, we can't prove causation, just show there's an association."
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