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.
No comments:
Post a Comment