In October, the World Health Organization (WHO) released a report that evaluated the association between cancer and eating processed and red meat. Among many proposals, the evaluation argued:
- The consumption of red meat is probably carcinogenic to humans, based on limited evidence that the consumption of red meat causes cancer in humans and strong mechanistic evidence supporting a carcinogenic effect.
- Processed meat is carcinogenic to humans based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer.
The news media immediately claimed that our beloved bacon has been added to the large list of “bad” foods. Yes, it is saddening that many of us will be conscientious of the carcinogenic impact each time we eat bacon or any kind of red or processed meat. However, instead of lamenting or discounting the evaluation, I think it’s important to look at the foundation and impact of the evaluation, as well as how it fits into the scientific process.
If the World Health Organization investigates processed and red meat’s link to cancer, I think it’s safe to say this is an important topic. The assessment was released by a subdivision of WHO called the International Agency for Research on Cancer (IARC) to address a public health concern and “support current recommendations to limit intake of meat.” It wasn’t written by one scientist and based on one or a few studies. The Working Group contained twenty-two scientists from ten countries, assessing more than 800 epidemiological studies that investigated the association of cancer with eating processed and red meat. The large number of existing studies on this association says scientists worry about this association. And when a panel of international experts finds even a slightly higher risk for cancer from eating red and processed meat, I think I’ll look for alternatives to eating my deli meat sandwich and having a side of bacon with my eggs.
But is it really worth it? How much can our diet affect whether or not we get cancer?
A recent study found that our environment, also called extrinsic factors (including our diet), has a lot of influence on whether or not we get cancer. One interpretation, along with the evaluation by the WHO, is that if we adjust our diets by cutting out processed and red meats, we may decrease our risk for cancer. Even though the current scientific evidence is limited on whether or not eating processed or red meat causes cancer, awareness of the association influences people and governments worldwide to make better, healthier decisions.
Though the WHO’s large-scale evaluation (much larger than a scientific review article) is not the norm within the scientific community, often it is appropriate because of impact on medical treatments, economics and society, or, in this case, the health of whole populations. We should keep in mind the scientific foundation the meat/cancer conclusions are based on. The studies looked at populations from multiple continents and from diverse ethnic and cultural backgrounds. This makes the current evidence too heterogeneous to establish how much meat in our diet results in cancer. The data is also too heterogeneous to specify if people of certain backgrounds are more at risk than others. As scientific investigations continue to contribute new evidence, then we may be able to form a more specific and accurate dietary recommendation for decreasing the risk of cancer globally. While we may not find these propositions favorable, the WHO evaluation represents our current understanding and addresses this public health concern to ultimately benefit people’s health worldwide.
Something that seems overlooked in the general public, and is often not discussed, is that any scientific topic, whether well studied or not, is constantly evolving. What is claimed in one study may be similar or contrary to findings in another study, due to many different factors. The growth of scientific evidence changes our knowledge, position, and standing on these topics as time progresses. We benefit from this scientific process by using accumulated data to impact innovation, technology, our well-being, and our basic understanding of nature. This has been the case with many scientific discoveries and theories, such as evolution, DNA as the information of life, and quantum theory. We can add meat and cancer to this ever-shifting list.
The WHO last October made conclusions based on the existing body of scientific evidence, which may not be perfect but was assessed properly, to decrease our chances of getting cancer. At the very least, we should respect that the evaluation represents the scientific process. We must understand the meat study was done so that we can make active choices to decrease our chances of getting cancer. So, the next time you skip on bacon with your breakfast, you may have made a healthier decision.
Photo by Jim Lo Scalzo / EPA. Source: http://bit.ly/1Pj00E8.