One of life's simple pleasures just got a little sweeter. After years
of waffling research on coffee and health, even some fear that java
might raise the risk of heart disease, a big study finds the opposite:
Coffee drinkers are a little more likely to live longer. Regular or
decaf doesn't matter.
The study of 400,000 people is the largest
ever done on the issue, and the results should reassure any coffee
lovers who think it's a guilty pleasure that may do harm.
"Our
study suggests that's really not the case," said lead researcher Neal
Freedman of the National Cancer Institute. "There may actually be a
modest benefit of coffee drinking."
No one knows why. Coffee
contains a thousand things that can affect health, from helpful
antioxidants to tiny amounts of substances linked to cancer. The most
widely studied ingredient — caffeine — didn't play a role in the new
study's results.
It's not that earlier studies were wrong. There
is evidence that coffee can raise LDL, or bad cholesterol, and blood
pressure at least short-term, and those in turn can raise the risk of
heart disease.
Even in the new study, it first seemed that coffee
drinkers were more likely to die at any given time. But they also tended
to smoke, drink more alcohol, eat more red meat and exercise less than
non-coffee-drinkers. Once researchers took those things into account, a
clear pattern emerged: Each cup of coffee per day nudged up the chances
of living longer.
The study was done by the National Institutes of
Health and AARP. The results are published in Thursday's New England
Journal of Medicine.
Careful, though — this doesn't prove that
coffee makes people live longer, only that the two seem related. Like
most studies on diet and health, this one was based strictly on
observing people's habits and resulting health. So it can't prove cause
and effect.
But with so many people, more than a decade of
follow-up and enough deaths to compare, "this is probably the best
evidence we have" and are likely to get, said Dr. Frank Hu of the
Harvard School of Public Health. He had no role in this study but helped
lead a previous one that also found coffee beneficial.
The new
one began in 1995 and involved AARP members ages 50 to 71 in California,
Florida, Louisiana, New Jersey, North Carolina, Pennsylvania and
Atlanta and Detroit. People who already had heart disease, a stroke or
cancer weren't included. Neither were folks at diet extremes — too many
or too few calories per day.
The rest gave information on coffee
drinking once, at the start of the study. "People are fairly consistent
in their coffee drinking over their lifetime," so the single measure
shouldn't be a big limitation, Freedman said.
Of the 402,260
participants, about 42,000 drank no coffee. About 15,000 drank six cups
or more a day. Most people had two or three.
By 2008, about 52,000
of them had died. Compared to those who drank no coffee, men who had
two or three cups a day were 10 percent less likely to die at any age.
For women, it was 13 percent.
Even a single cup a day seemed to
lower risk a little: 6 percent in men and 5 percent in women. The
strongest effect was in women who had four or five cups a day — a 16
percent lower risk of death.
None of these are big numbers, though, and Freedman can't say how much extra life coffee might buy.
"I really can't calculate that," especially because smoking is a key factor that affects longevity at every age, he said.
Coffee
drinkers were less likely to die from heart or respiratory disease,
stroke, diabetes, injuries, accidents or infections. No effect was seen
on cancer death risk, though.
Other research ties coffee drinking
to lower levels of markers for inflammation and insulin resistance.
Researchers also considered that people in poor health might refrain
from drinking coffee and whether their abstention could bias the
results. But the study excluded people with cancer and heart disease —
the most common health problems — to minimize this chance. Also, the
strongest benefits of coffee drinking were seen in people who were
healthiest when the study began.
About two-thirds of study
participants drank regular coffee, and the rest, decaf. The type of
coffee made no difference in the results.
Hu had this advice for coffee lovers:
— Watch the sugar and cream. Extra calories and fat could negate any benefits from coffee.
— Drink filtered coffee rather than boiled — filtering removes compounds that raise LDL, the bad cholesterol.
Researchers did not look at tea, soda or other beverages but plan to in future analyses.
Lou
and Mariann Maris have already compared them. Sipping a local brew at a
lakefront coffee shop, the suburban Milwaukee couple told of how they
missed coffee after briefly giving it up in the 1970s as part of a
health kick that included transcendental meditation and eating
vegetarian.
Mariann Maris switched to tea after being treated for
breast cancer in 2008, but again missed the taste of coffee. It's one of
life's great pleasures, especially because her husband makes it, she
said.
"Nothing is as satisfying to me as a cup of coffee in the morning," she said.
___
Online:
New England Journal: http://www.nejm.org
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