The Fear of Red Meat
The Fear of Red Meat
Before we continue any more on ketogenic dieting there is one elephant in the room that we need to address. Very recently, there was a report published by WHO (Bouvard & Véronique, et al., 2015) that resulted in a great stir in the media. This report led to the media posting various articles and news reports with titles delivering information that red meat is linked to a high risk for cancer (O'connor, Anahad. "Meat Is Linked to Higher Cancer Risk, W.H.O. Report Finds." The New York Times. The New York Times, 26 Oct. 2015. Web. 2 Dec. 2015.) and that bacon should be considered as hazardous to our health as smoking (McAteer, Ollie. "Bacon Is as Bad as Smoking and That Makes Us Sad." Metro Bacon Is as Bad as Smoking and That Makes Us sad Comments. 23 Oct. 2015. Web. 2 Dec. 2015.). Is this what the researchers actually found or did the media again misconstrue information?
Key Point 1: The review that the media was referring to took place when 22 researchers met at the International Agency for Research on Cancer to discuss over 800 papers regarding red meat and processed red meat. After reviewing these papers, researchers concluded that PROCESSED red meat is carcinogenic to people. The researchers defined processed red meat as, “meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation.” Unprocessed red meat was labeled as a possible carcinogen to humans. This is the first piece of information that was left out of most articles discussing this review. This small piece of information alone changes the dynamic of the information. It is also crucial to note that this conclusion was referring to a specific type of cancer (colorectal cancer), which cannot be generalized to all forms of cancer.
Key Point 2: Another very important factor that is worth mentioning is that many of the studies reviewed by the researchers were observational studies, meaning they followed people over a period of time and tried to determine what factors led to an increase in the risk for cancer. These studies are difficult to interpret because there are many other factors that could have led to the results. The majority of these studies did not control for things like diet or exercise. In fact, some of these studies could be as simple as; this group of people who claimed to consume a diet high in red meat had a higher prevalence of cancer. Information like, “Was the majority of the red meat consumption from processed red meats?” was failed to be taken into consideration. Were the diets also high in carbohydrates? Did the population consist of sedentary individuals? What other habits did these people have that could have attributed to the development of cancer? Were they sitting on their couch eating Doritos all day? Were the subjects in these studies already predisposed to cancer (obese populations)? We just don’t know what other possible factors played a role in the findings. The majority of these questions have gone unanswered which is why it is so difficult to make a cut and dry assumption that red meat directly causes cancer.
One of the major concerns with red meat are nitrates and nitrites. Certain metabolites of nitrates can be hazardous to human health, and specifically gut health. Nitrites and nitrates used in the preservation of processed meat are converted into nitrosamines by binding to amino compounds, either in the stomach or within the food (Pan et al., 2011). One thing that most people do not know is that it is the chemicals contained in processed red meat that lead to these nitrates having a greater negative impact on gut health. Several of the chemicals contained in processed red meats can accelerate the formation of these harmful metabolites of nitrates. However, unprocessed red meats do not contain these same chemicals, meaning that that could be one of the major differences between processed and unprocessed red meat. Also to combat this concern, a diet high in leafy green vegetables has been shown to be beneficial for reducing the risk of these nitrates on gut health. There have been many animal studies that have shown that vegetable consumption can have an antitumorigenic effect (Ikken et al., 1999). Ikken et al. (1999) also found that certain extracts found in vegetables have the ability to prevent the harmful nature of nitrosamines. This brings up a very interesting point; how many of the people in these studies were also consuming the appropriate amount of vegetables? It is possible that some individuals were balancing out their red meat consumption with vegetable consumption, but if I had to guess a great portion of the population who normally tend to consume a high red meat diet are likely not providing adequate vegetable consumption. An additional concern with red meat is HCA’s (heterocyclic amines). HCA’s have been linked to the development of cancer and are produced through food preparation at high temperatures. Thus, the appearance of these chemicals occur when red meat is either charred or cooked at too high of a temperature (which can be reduced). A review by Kamel Patel also points out that the consumption of green vegetables can combat these chemicals as well certain marinades and spices. Smith et al., 2008 discovered that Carribean, Southwest, and herb based marinades reduced the formation of HCA’s.
There are several other factors that people tend to dismiss when looking at reviews such as this one. For instance, how many studies used for this review looked at the consumption of red meat and ketogenic dieting, or better yet a well-formulated ketogenic diet (which we will discuss in future posts)? Another idea that needs to be considered is moderation. There are many things that are harmful to our bodies in excessive amounts, which is why there could be value to limiting the intake of processed red meats when consuming a ketogenic diet. It is important to understand that by no means am I making the claim that red meat consumption during a ketogenic diet could not have potential risks for something like cancer. To put it simply, we do not know. However, based on research from a good friend of the lab, Dr. Dominic D’Agostino, it appears it may have the opposite affect (Poff et al., 2015).
Clearly, we have our work cut out for us as researchers in regards to the carcinogenic effect of red meat. We have to make sure we do not generalize beyond the population and conditions provided in a study. Lastly, it never hurts to get in some more leafy green vegetables in your diet!
References
Bouvard, Véronique, et al. "Carcinogenicity of consumption of red and processed meat." The Lancet. Oncology (2015)
Ikken, Youssef, et al. "Antimutagenic effect of fruit and vegetable ethanolic extracts against N-nitrosamines evaluated by the Ames test." Journal of Agricultural and Food Chemistry 47.8 (1999): 3257-3264.
McAteer, Ollie. "Bacon Is as Bad as Smoking and That Makes Us Sad." Metro Bacon Is as Bad as Smoking and That Makes Us sad Comments. 23 Oct. 2015. Web. 2 Dec. 2015.).
O'connor, Anahad. "Meat Is Linked to Higher Cancer Risk, W.H.O. Report Finds." The New York Times. The New York Times, 26 Oct. 2015. Web. 2 Dec. 2015
Pan, An, et al. "Red meat consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis." The American journal of clinical nutrition 94.4 (2011): 1088-1096.
Poff, A. M., et al. "Non-Toxic Metabolic Management of Metastatic Cancer in VM Mice: Novel Combination of Ketogenic Diet, Ketone Supplementation, and Hyperbaric Oxygen Therapy." PloS one 10.6 (2015).
Smith, J. S., F. Ameri, and P. Gadgil. "Effect of marinades on the formation of heterocyclic amines in grilled beef steaks." Journal of Food Science 73.6 (2008): T100-T105.
