May 16, 2012, 6:18 p.m.
Researchers have some reassuring news for the legions of coffee drinkers who can't get through the day without a latte, cappuccino, iced mocha, double-shot of espresso or a plain old cuppa joe: That coffee habit may help you live longer.
A new study that tracked the health and coffee consumption of more than 400,000 older adults for nearly 14 years found that java drinkers were less likely to die during the study than their counterparts who eschewed the brew. In fact, men and women who averaged four or five cups of coffee per day had the lowest risk of death, according to a report in Thursday's edition of the New England Journal of Medicine.
The research doesn't prove that coffee deserves the credit for helping people live longer. But it is the largest analysis to date to suggest that the beverage's reputation for being a liquid vice may be undeserved.
"There's been concerns for a long time that coffee might be a risky behavior," said study leader Neal Freedman, an epidemiologist with the National Cancer Institute who drinks coffee "here and there." "The results offer some reassurance that it's not a risk factor for future disease."
Coffee originated in Ethiopia more than 500 years ago. As it spread through the Middle East, Europe and the Americas, its popularity was tempered by concerns about its supposed ill effects. A 1674 petition by aggrieved women in London complained that coffee left men impotent, "with nothing moist but their snotty noses, nothing stiff but their joints, nor standing but their ears," according to the book "Uncommon Grounds: The History of Coffee and How It Transformed Our World."
In more modern times, the caffeinated beverage has been seen as "a stimulating substance, a commonly consumed drug," said Rob van Dam, an epidemiologist at the National University of Singapore who has investigated the drink's health effects but was not involved in the latest study.
"People get somewhat dependent on it," Van Dam said. "If you try to rapidly reduce coffee consumption, you get headaches or other symptoms."
The National Coffee Assn. estimates that 64% of American adults drink coffee on a daily basis, with the average drinker consuming 3.2 cups each day. To get a deeper understanding of the risks and benefits of all that joe, the National Cancer Institute researchers turned to data on 402,260 adults who were between the ages of 50 and 71 when they joined the NIH-AARP Diet and Health Study in 1995 and 1996. The volunteers were followed through December 2008 or until they died — whichever came first.
When the team first crunched the numbers, coffee seemed to have a detrimental effect on longevity. But people who drink coffee are more likely to smoke, and when the scientists took that into account (along with other demographic factors), the opposite appeared to be true.
Compared with men who didn't drink any coffee at all, those who drank just one cup per day had a 6% lower risk of death during the course of the study; those who drank two to three cups per day had a 10% lower risk, and those who had four to five cups had a 12% lower risk. For men who drank six cups or more, the apparent benefit waned slightly, with a 10% lower risk of death during the study compared with men who drank no coffee.
The relationship between coffee and risk of death was even more dramatic in women. Those who drank one cup per day had 5% lower odds of dying during the study compared with women who drank none. Those who consumed two or three cups a day were 13% less likely to die, those who downed four or five cups were 16% less likely to die, and those who drank six or more cups had a 15% lower mortality rate.
The effect held across a number of causes of death — including heart disease, respiratory disease, stroke and diabetes — but not cancer, the researchers found. And the link was stronger in coffee drinkers who had never smoked.
The correlation even held for people who mostly drank decaf brew, the researchers found.
"If these are real biological effects, they seem to [have] to do with the substances in coffee that are not caffeine," Van Dam said. Other compounds in the coffee could be linked to the lower death rates, he said — or there could be no causal relationship at all.
And, Van Dam added, the researchers didn't make distinctions between different types of drinks. Unfiltered brews like Turkish coffee or Scandinavian boiled coffee have been shown to raise cholesterol and could present very different results from the current study if examined separately, he said.
To prove that coffee deserves the credit, researchers could study each of the 1,000-odd compounds in the brew and test them on subjects over time to see if they reduced inflammation, improved the body's sensitivity to insulin or caused any other useful biological effects, he said.