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Wednesday, July 04, 2012

Drinking coffee, longer life

Last May, The New England Journal of Medicine published striking results from a clinical study showing that drinking coffee results in a reduction in mortality from all causes except cancer. Surprisingly, drinking more than 6 cups a day was better than drinking just one or two. And even more suprisingly, decaffeinated coffe had the same effect than regular coffee.

It is not unccommon to read articles in the press talking about how wonderful certain foods, vitamins, or natural products are for your health. Most of these articles are written with no scientific data to back them up. How many times haven’t we read or heard that a particular food or natural product prevents whatever disease?

But this coffee study I am refering to was not published in any journal. It was published in the most prestigious medical journal in the world. This does not mean that what the article says should be taken as the absolute truth. Even the best scientific journals publish results from studies that cannot be reproduced by others. But to be published in the New England Journal of Medicine, an article has to go through what is arguably the most rigorous peer review process, and thus deserves attention.

The study was a survey of over half a million people who were then followed for many years. The amount of coffee that each individual drank was determined during the first interview. Many factors that could influence the results, such as tobacco consumption, other medical conditions, etc., were taken into account in the statistical analysis. The main result is that those who drank more coffee lived more years.

The authors of the study cannot determine whether the association between coffee and reduced mortality was causal (coffee directly protects from dying) or just an association (both coffee drinking and longer lifespan occur in the same people because of other factors not controlled for).

In any case, if you were worried because of your coffee drinking habits, it appears that your fear is not justified.



Neal D. Freedman, Ph.D. et al. Association of Coffee Drinking with Total and Cause-Specific Mortality. N Engl J Med 2012;366:1891-904.

http://www.nejm.org/doi/full/10.1056/NEJMoa1112010

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