Earlier this week, experts from the World Health Organization (WHO) announced that eating processed meat can lead to bowel cancer in humans, while red meat is likely a cause of the disease. Since this hit the news, a debate on the merits of a meat-based diet has raged. The France-based International Agency for Research on Cancer (IARC), part of the WHO, placed processed meats such as ham and hot dogs in its group 1 list, along such substances as tobacco, asbestos and diesel fumes, saying that there is “sufficient evidence” of cancer links.
While the risk of developing bowel cancer from eating processed meat remains small, the risk increases with the amount of meat consumed. Red meat, categorized by the IARC as beef, lamb and pork, was classified as a “probable” carcinogen in its group 2A list that also contains glyphosate, the active ingredient in many weedkillers. The lower classification for red meat reflected the “limited evidence” that it causes cancer. While the IARC found links with bowel cancer for the most part, it also observed that there were associations with pancreatic and prostate cancer.
The agency, whose findings on meat followed a meeting of health experts in France earlier this month, estimated that each 50 gram portion of processed meat eaten daily increases the risk of bowel cancer by 18 percent. The IARC, which was assessing meat for the first time and reviewed some 800 studies, doesn’t compare the level of cancer risk associated with products in a given category, so it doesn’t suggest that eating meat is as dangerous as something like smoking. In some countries, health policy has already called for consumers to limit their intake of red and processed meat, although most of that was focused on heart disease and obesity.
The preparation of the IARC’s report has already led to vigorous responses from the meat industry, who argue that meat forms part of a balanced diet and that cancer risk needs to be set in a broader context of various factors. The IARC, which doesn’t make specific policy recommendations, cited an estimate from the Global Burden of Disease Project, an international consortium of over 1,000 researchers, that 34,000 cancer deaths every year are attributable to diets high in processed meat. Compare this to about 1 million cancer deaths from tobacco smoking, 600,000 due to alcohol consumption and over 200,000 from air pollution. If the cancer link with red meat is confirmed, then the Global Burden of Disease Project says that red meat diets could be the cause of 50,000 deaths a year.