It’s fairly common knowledge that regular red meat consumption is a risk factor for most cancers. There are several plausible biological mechanisms that link red meat to cancer.
The Possible Mechanisms:
Specifically:
- Population studies show that people who eat the most red meat tend to have the highest rates of cancer.
- Red meat contains the heme form of iron. Unless you are deficient in iron, excess of the heme form can be damaging to the lining of the colon and produce N-nitroso compounds in the intestines, which are cancer causing.
- Cooking red meat at high temperatures can produce cancer promoters. We see these as char marks.
However, recent research states that it is an anti-body reaction to a sugar molecule found on red meat that triggers cancer and inflammation, rather than the theories above.
The Research
Samraj AN & Pearce OMT, et al questioned why red meat consumption was linked to increased rates of cancer in humans but not in other animals. In their study, mice were fed a diet high in red meat and were injected with the antibodies hypothesized to be produced in humans in response to eating red meat. As a result, many mice developed tumors, most commonly liver cancer [i].
Limitations
There are some limitations to consider. First off, the study was conducted in mice and not humans. Thus, we cannot be sure if humans would produce the same amount of antibodies in response to eating red meat that was injected into the mice and if the antibodies would cause the same amount of harm in humans as it did in the mice. In addition, the mice were constantly fed the red meat. Humans do not typically consume one food for all meals, every day. Lastly, the meat used for the study was bought from local supermarkets. It is not clear if this meat was conventional, “corn fed” red meat, which is thought to be more inflammatory than grass fed red meat.
Take away
For people who are iron deficient, it is likely okay to eat some red meat in addition to other high iron foods like beans and greens. The American Institute of Cancer Research recommends eating no more than 18 oz of red meat per week. In order to optimize potential benefits from eating red meat, try to choose a grass fed beef whenever possible and choose your vegetables first and think of red meat as a occasional food and/or a side dish rather than the main dish.
Overall, there are several risk factors that can lead to cancer. From a dietary perspective, it is not one food that causes cancer but an overall dietary pattern that is considered to be inflammatory and is lacking in plant based foods.
References
[i] Samraj AN, Pearce OMT, et al. A red meat-derived glycan promotes inflammation and cancer progression. PNAS. 2014. 10.1073/pnas.1417508112
