Washington (AFP)
Many countries recommend limiting the consumption of red meat and cold cuts to prevent cancer and heart disease, but a review of dozens of studies by independent researchers concludes Monday that the potential risk is low and the evidence uncertain, creating a scientific storm.
In new guidelines, a panel of researchers from seven countries "advises adults to continue their current consumption of red meat," which is an average of three to four servings a week in North America and Europe. Same instruction for deli, according to these recommendations published Monday in the Annals of Internal Medicine, published by the American College of Physicians.
Multiple studies re-analyzed collectively by the group indicate that reducing red meat consumption by three servings per week could lower cancer mortality by seven deaths per thousand people, which researchers see as a modest decline. In addition, they insist: the degree of certainty of this statistic is "low".
For sausage and cardiovascular diseases and diabetes, the quality of evidence is considered "very low" by the team, which used a methodology called GRADE.
"There are very low risk reductions for cancer, heart disease and diabetes, and the evidence is uncertain," says Bradley Johnston, Associate Professor of Epidemiology at Dalhousie University in Canada. director of the NutriRECS group, who wrote the instructions.
"Maybe there is a risk reduction, or maybe not," he told AFP.
With their new analysis, researchers say they want to mature the field of nutritional recommendations, they consider representative of an "old school" too focused on societal benefits and not individual, in order to move towards a medicine more personalized.
They say that generally authoritative recommendations do not sufficiently argue that the absolute risk remains low, and that it remains very difficult to isolate the effect of a particular food over a lifetime, multiple causes other than diet that can affect health.
"We deliver to people our best estimate of the truth, which is uncertain: according to their own preferences, they may decide to reduce or eliminate" meat and sausage, "says Bradley Johnston.
"But our recommendation is that for most people, the best approach is to continue, given the very low risk reduction and the uncertainty of the evidence."
- Individual choices -
Reducing the consumption of red meat and cold cuts is a cornerstone of nutritional recommendations in many countries.
The latest edition published in January by Santé Publique France recommends, for example, limiting delicatessen to 150 grams per week and meat other than poultry to 500 grams.
The International Agency for Research on Cancer, an agency of the World Health Organization, classifies red meat as a "probable carcinogen" and charcuterie as "carcinogenic".
The instructions issued Monday have provoked a volley of criticism in the world of experts in nutrition and epidemiology, that is to say the discipline studying the relationship between diseases and the factors that can cause them.
While approving the rigor of the new analyzes, many differed on the philosophy of the conclusions.
The risk of colorectal cancer associated with cold cuts may be low, so says Professor Tim Key, deputy director of Oxford's Cancer Epidemiology Unit, but at a population level he is not negligible.
The Word Cancer Research Fund said it would not change its guidelines: "We maintain our confidence in the rigorous research conducted for 30 years," said its director of research, Giota Mitrou.
"It is depressing that everything tends to indicate that after all these years and millions of study participants, we still do not know much," concludes Kevin McConway, emeritus professor of statistics at the Open University .
The instructions issued Monday were approved by 11 of the 14 researchers making up the panel.
"People should use this to make better informed choices, rather than organizations telling them authoritatively what to do," says Bradley Johnston.
© 2019 AFP