Drink coffee, live longer. It seems strange, but the science is compelling.

So what's with the health benefits of coffee?

New studies suggest you will live longer drinking coffee than from taking vitamins, eating good fruits and engaging in the latest "miracle diet" craze.

It's not entirely clear why. Its not the caffeine, because even decaf coffee has the impact of reducing mortality by statistically significant amounts.

One British study released this month followed half a million people over 10 years, and found not only that coffee drinkers live longer, but that the more coffee you drink, the better your chances of a longer life than those who drink less.

The study is entitled "Association of Coffee Drinking with Mortality by Genetic Variation in Caffeine Metabolism." It was published in the journal JAMA Internal Medicine, a publication of the American Medical Association, by authors are Erikka Loftfield, Marilyn Cornelis, Neil Caporaso, Kai Yu, Rashmi Sinha and Neal Freedman.

The study was designed to look into whether drinking a lot of coffee is a problem for people with genetic issues with caffeine metabolism, but it found that everyone—including those whose caffeine metabolism was faster or slower—had reduced mortality if they drank coffee.

This isn’t entirely new. There have been previous studies linking coffee to better longevity and to reduced rates of various diseases. That helped lead to the recommendation that up to 40 ounces of coffee (five 8-ounce cups) can be part of a healthy diet, from the 2015 report of the U.S. Dietary Guidelines Advisory Committee.

This new study is a massive study using the more than 9 million members of the UK Biobank. This study targeted 503,000 volunteers—excluding those who were pregnant, or whose coffee or nicotine intake information was incomplete. It looked at those who drink ground coffee, instant coffee and decaffeinated coffee. The average age going into the study was 57, and there were slightly more women than men. The researchers followed them for 10 years, during which time more than 14,000 of them died

People lived longer, even if they drank decaf—so it's something in the coffee or the coffee drinking, and not just the caffeine. "These findings suggest the importance of noncaffeine constituents in the coffee-mortality association and provide further reassurance that coffee drinking can be a part of a healthy diet," the study's authors write.

The authors looked at details of participants' smoking, as well as sex, weight, exercise, race, education and how much they also drank tea (it is a British survey, after all). A fifth were non-coffee-drinkers.

Ground coffee was a little healthier than instant and decaf, but they were all better than none. The study found that sex, age, weight and previous health issues did not make much difference in the outcome.

The study 's conclusion ends with this key message: "Our results provide further evidence that coffee drinking can be part of a healthy diet and may provide reassurance to those who rink coffee and enjoy it."

An earlier study of 400,000 people was published in 2012, in an edition of the New England Journal of Medicine. It had similar results. The study was entitled "Association of Coffee Drinking with Total and Cause-Specific Mortality," and was by Neal D. Freedman, Yikyung Park, Christian C. Abnet, Albert R. Hollenbeck, and Rashmi Sinha. Freedman and Sinha were authors of both papers that we discuss here.

They followed 230,000 men and 170,000 women aged 50 to 71 over 13 years, during which period about 50,000 of them died. The study found that people who drink several cups of coffee daily have lower mortality—they don't die as early as ones who don't drink coffee or who drink less coffee.

This is particularly noteworthy—and strange—because coffee drinkers tend to make bad lifestyle choices:

"As compared with persons who did not drink coffee, coffee drinkers were more likely to smoke cigarettes and consume more than three alcoholic drinks per day, and they consumed more red meat. Coffee drinkers also tended to have a lower level of education; were less likely to engage in vigorous physical activity; and reported lower levels of consumption of fruits, vegetables, and white meat. However, coffee drinkers, especially women who drank coffee, were less likely to report having diabetes. About two thirds of coffee drinkers reported drinking predominantly caffeinated coffee.

Still, according to both studies, if you drink three to five cups of coffee a day, even decaffeinated coffee, you're roughly 10 percent less likely to die in a given period.

What the heck is going on? Everybody knows about the caffeine, but if the decaf drinkers get the same protective effect (which may mean that caffeinated soft drinks don't do the same thing, incidentally) what's causing the reduce mortality?

Well, it turns out there are about 1,000 other compounds in coffee. So it might be one or more of those things.

The authors point out that they can't prove the coffee causes the health effect. It might be that something else about coffee drinkers is making them less likely to die as soon.

If it is not caffeine having an effect, maybe it's antioxidants, the authors of the 2012 paper suggest.

"Coffee contains more than 1000 compounds that might affect the risk of death. The most well-studied compound is caffeine, although similar associations for caffeinated and decaffeinated coffee in the current study and a previous study suggest that, if the relationship between coffee consumption and mortality were causal, other compounds in coffee (e.g., antioxidants, including polyphenols) might be important.

There's also a 2017 study in the Annals of Internal Medicine of coffee drinkers in 10 European countries. It had similar results: " Coffee drinking was associated with reduced risk for death from various causes. This relationship did not vary by country." 

Still, this research isn't entirely straightforward. This article from the Mayo Clinic suggests that while there may be health benefits from coffee, there are also risks for some folks. 

Oh, and taking vitamins and supplements? One study says "the results from controlled trials are dismal."

Another, on antioxidant vitamins in heart health says: "After an initial enthusiasm for antioxidants in the secondary prevention of cardiovascular disease, recent reports from of several large randomized trials have failed to show any beneficial effects." 

The takeaway seems to be that it's healthier to eat a good diet with lots of fruits and vegetables than to take supplements to make up for a bad diet. But also, that there might be some benefit to having a couple of cups of coffee with those leafy meals.

© Jan TenBruggencate 2018