On October 26th, 2015 the International Agency for Research on Cancer (IARC) issued a press release that the consumption of red meat and processed red meat causes cancer. Over the past 24 hours this has created a media frenzy.
Here at Brooklyn Health and Performance, we believe in going to the source when it comes to health and medical reports released by the media. The IARC is the cancer research division of the World Health Organization (WHO). The statement that particular meats may be carcinogenic actually originates from the conclusions of a month long working group of 22 scientists from 10 countries reviewing 800 epidemiological or statistical studies which have investigated the association of cancer with both processed red meat and red meat itself. Of note, the details of this evaluation have not yet been published. All of the information we are hearing on the news comes from a press release as well as a summary published in The Lancet Oncology Journal.
According to the summary, the panel assessed nearly 1,000 epidemiological studies from diverse countries with different diets over a period of 20 years. Preference was given to studies with the largest sample sizes and fewest biases and confounding factors as well as prospective analysis (follows similar individuals over time) over retrospective (looks back at events). Although these would be considered the more powerful studies, there are likely still many limitations in each of the studies individually and cumulatively. As a result, we must question the accuracy of these calculated statistics and how they apply to the health of the world’s population.
The analyzed data was predominantly associated with colorectal cancer. The largest meta-analysis evaluated 10 cohort studies (type of observational study following a group of people over time) and showed an 18% increase in risk of colorectal cancer per 50g per day of processed meat. A meta-analysis combines the statistics of multiple studies, therefore that 18% may be higher or lower based on a multitude of other factors including health and diet. There is no mention of level of health and fitness of the individuals followed in the studies.
To develop a sense of scale when reading these statistics, it is a well established fact that smoking cigarettes increases someone’s risk for developing lung cancer. According to the Centers for Disease Control, smoking cigarettes can increase the risk of developing lung cancer by over 1,500%. According to the press release from the IARC, processed meats can increase someone’s risk for colorectal cancer by up to 18%.
Interestingly, the article clearly states that “there is inadequate evidence in experimental animals for the carcinogenicity of the consumption of red meat and processed red meat.” Therefore, there is no direct data unlike other carcinogens such as cigarettes which has been compared to red meat in the media. Furthermore, there was no mention of the quality of the meat such as grass fed, organic, etc.
Our final conclusion is that a highly reputable authority has classified consumption of processed red meat as Group 1 (carcinogenic to humans) and consumption of red meat as Group 2A (probably cancer-causing) for colorectal cancer. The available data raises a theoretical concern but there is no definitive evidence. Red meat has significant nutritional value and is an important part of the American diet. The risk of colorectal cancer to the average individual is likely very low even based on the results of this analysis. We must weigh the risks and benefits in making any decisions about health and diet. Exercise and optimal fitness must not be overlooked when it comes to health and prevention of cancer. It is important to be well informed and not panic and overreact to media headlines.