By TARA PARKER-POPE New York Times
Your morning cup of coffee may start to taste even better after a major government study found that frequent coffee drinkers have a lower risk of dying from a variety of diseases, compared with people who drink little or no coffee.
The report, published online in The New England Journal of Medicine on Wednesday, analyzed the coffee-drinking habits of more than 400,000 men and women ages 50 to 71, making it the largest-ever study of the relationship between coffee consumption and health.
Previous studies have offered conflicting results on the relative benefits or harms associated with regular coffee consumption. While coffee contains caffeine, a stimulant that may temporarily increase heart rate and blood pressure in some people, coffee also contains hundreds of unique compounds and antioxidants that may confer health benefits. Further confusing much of the research into coffee is the fact that many coffee drinkers are also smokers, and it has been difficult to untangle the relative health effects of coffee and cigarettes.
To learn more, researchers from the National Institutes of Health analyzed diet and health information collected from questionnaires filled out by 229,119 men and 173,141 women who were members of the American Association of Retired Persons (AARP) between 1995 and 1996. The respondents were followed until 2008, by which point 52,000 had died.
As expected, the researchers found that the regular coffee drinkers in the group were also more likely to be smokers. They ate more red meat and fewer fruits and vegetables, exercised less and drank more alcohol – all behaviors associated with poor health.
But once the researchers controlled for those risks, the data showed that the more coffee a person consumed, the less likely he or she was to die from a number of health problems, including diabetes, heart disease, respiratory disease, stroke, infections and even injuries and accidents.
Over all, the risk of dying during the 14-year study period was about 10 percent lower for men and about 15 percent lower for women who drank anywhere from two cups to six or more cups of coffee a day. The association between coffee and lower risk of dying was similar whether the coffee drinker consumed caffeinated or decaffeinated coffee.
Neal D. Freedman, the study’s lead author and an investigator for the National Cancer Institute, cautioned that the findings, based on observational data, show only an association between coffee consumption and lower risk for disease, so it isn’t known whether drinking more coffee will lead to better health. As a result, Dr. Freedman said that people should be conservative in interpreting the data, but that regular coffee drinkers can be reassured.
“It’s a modest effect,” he said. “But the biggest concern for a long time has been that drinking coffee is a risky thing to do. Our results, and some of those of more recent studies, provide reassurance for coffee drinkers that this isn’t the case. The people who are regularly drinking coffee have a similar risk of death as nondrinkers, and there might be a modest benefit.’’
The researchers also looked at death rates from cancer during the study period and found no link between coffee consumption and cancer risk among women. There was a slightly higher risk of cancer death among men who drank several cups of coffee a day, but Dr. Freedman said the effect was small and may be due to chance. Additional research will analyze associations between coffee drinking and various types of cancer.
Dr. Freedman said the next step is to learn more about the various compounds in coffee and how they may be related to improved health.
“It’s estimated there are 1,000 or more compounds in coffee,’’ said Dr. Freedman. “All of these could affect health in different ways. It might be due to one of the many compounds in coffee, or a number of them working together.”