Drinking more coffee is associated with a longer life, according to new research

There's something truly magical about a cup of coffee. A steaming cup in the morning can help you face the day, a sweating glass of iced coffee will perk you up in the afternoon heat, and a warm mug after dinner helps settle your meal.

Yet people frequently try to limit their coffee consumption for health reasons, fearing negative effects.

Two major studies published July 10 in the journal Annals of Internal Medicine, however, should help assuage those fears.

The studies involved more than 700,000 people and found that the more coffee individuals consumed, the less likely they were to die an early death from a number of diseases including cancer, diabetes, and heart disease.

And for those who don't want to consume more caffeine, don't worry — decaf seems to offer the same health benefits.

More coffee, lower risk of death

For the larger of the two new studies, researchers analyzed data from a nutrition study that tracked more than 520,000 people from 10 European countries for an average of 16.4 years. The more coffee those participants consumed, the lower their risk of death, researchers found.

The top 25% of coffee drinkers in the study had three or more cups a day. Among that group, men were 12% less likely to die early than comparable people who avoided coffee completely. And women who consumed a lot of coffee were 7% less likely to die early.

In addition to lower general risk of early death, researchers found reduced risk of death from diseases of the digestive system and circulatory system. For men, coffee consumption was also associated with a lower risk of suicide.

The second study followed the diet and health habits of 185,855 Americans for just over 16 years and found similar reductions in risk of death — in this case from heart disease, cancer, respiratory disease, stroke, diabetes, and kidney disease. Compared to people who didn't drink coffee at all, people who drank two to three cups per day were 18% less likely to die early. People who drank one cup a day were 12% less likely to die than those who abstained.

This second study was particularly noteworthy because it focused on American populations of different ethnicities, including black, white, Latino, Japanese, and Hawaiian-Americans. Most previous studies on the effects of coffee on longevity have focused on people of European descent.

Causation versus correlation

These studies are observational, meaning they can't establish cause and effect — no one can say based on this data that drinking more coffee will definitely extend your life. The researchers tried to control for factors like diet, obesity, and smoking status, but it's still possible that people who consume coffee are already healthier in some way they didn't control for.

However, this isn't the first research to indicate that coffee may improve your health. In both studies, authors noted that previous research has found coffee consumption to be associated with improvements in liver function, blood sugar levels, and inflammation.

Since decaf coffee was also associated with improved longevity, it's probably not the caffeine that's responsible for these benefits, even if that's the reason most of us drink coffee. In an editorial published alongside the studies, a group of researchers speculated that the benefits of coffee may come from other compounds that are extracted when the beverage is prepared, especially antioxidant polyphenols. (Caffeine may still have some benefits, though.)

Even if we don't know whether coffee causes this increased longevity, these new findings suggest that people shouldn't feel guilty about their coffee consumption. Drinking unlimited amounts of caffeinated coffee could eventually put you at risk, but up until about five cups per day, the researchers say you don't need to worry.