After years of research without definitive results on the relationship between coffee and health and they are even afraid that coffee raised the risk of developing heart disease, a new large study found the opposite: coffee drinkers tend to live a little longer, no matter who consume regular or decaf.
“Our study indicates that this is not the case,” said lead researcher Neal Freedman, the National Cancer Institute. “In fact there could be a modest benefit of drinking coffee.”
No one knows why. Coffee contains a thousand things that can affect health, from antioxidants useful even small amounts of cancer-related substances. Its most studied ingredient (caffeine) was not part of the new study results.
Not that the previous studies were flawed. There is evidence that coffee can raise bad cholesterol and blood pressure in the short term, and these in turn may increase the risk of developing heart disease.
Even in the current study, at first it seemed that coffee drinkers died at a higher rate, but also tend to smoke, drink more alcohol, eat more red meat and exercise less than non-coffee drinkers. Once the researchers considered such factors, there was a clear pattern: each cup of coffee a day increases the chances of living longer.
The study was conducted by the National Institutes of Health and the AARP. The results were published in the New England Journal of Medicine.
However, all this does not prove that coffee makes people live longer: only seems to have a relationship. Like most studies of diet and health, this is strictly based on observation of the habits of people and resulting health status, so it does not prove cause and effect.
However, with so many people involved in the study, more than a decade of monitoring and enough deaths to compare, “this is perhaps the best evidence we have,” and might have, said Dr. Frank Hu of the School of Public Health at Harvard University.
Hu did not participate in the study but helped lead a prior who also discovered benefits of coffee.
The new study began in 1995 and involved AARP members between 50 and 71 years were based in California, Florida, Louisiana, New Jersey, North Carolina, Pennsylvania, Atlanta and Detroit. We did not include people who already had cardiovascular diseases or cancer. Individuals who did not participate diets take too many calories per day or too few.
The rest gave information on coffee consumption only once, at baseline.
“People are quite stable in coffee consumption over their life,” so the only measurement should not be a relevant constraint, Freedman said.
Of the 402 000 260 participants, about 42 000 did not drink coffee. Some 15mil drank six cups or more a day. Most took two or three.
By 2008, some 52 000 had died. Compared with coffee nondrinkers, men who drank two or three cups a day had 10% less likely to die at any age. For women, the difference was 13%.
Even one cup a day seemed to reduce the risk a bit: 6% in men and 5% in women. The effect was strongest in women who drank four or five cups a day, with 16% less risk.
None of these is a large number, and Freedman could not say how much extra life you get with coffee.
“I can not really calculate it,” he said, especially because smoking is a key factor affecting longevity at any age.
Coffee drinkers were less likely to die from heart or respiratory diseases, stroke, diabetes, injuries, accidents or infections. We did not detect any effect on risk of death from cancer.
About two thirds of study participants drank regular coffee, the rest decaf. The type of coffee is not marked difference in the results.