The Red Meat-Cancer Debate: What the Science Really Says

A couple of years ago during one of our livestreams, Dr. Bikman critically examined the widespread notion that red meat consumption causes cancer. The clip got buried in a mountain of content and was never published—so we’d like to share it today.

Ben begins by highlighting the World Health Organization’s classification of red meat as a “Group 2A carcinogen,” meaning it is “probably carcinogenic.” He explains that this claim is based on correlational studies, which can only establish coincidence, not causation. Ben emphasizes that no human studies have conclusively shown that red meat causes cancer because such studies would require tightly controlled, long-term dietary adherence, which is unfeasible.

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Ben discusses several studies to illustrate the nuances of the red meat-cancer debate. While some studies report modest increases in cancer risk associated with red meat consumption, others show no correlation or even an inverse relationship. He critiques the reliance on relative risk statistics in these studies, which can exaggerate findings, and highlights factors like healthy user bias, cooking methods, and gut microbiota differences as potential confounding variables. Despite conflicting data, Dr. Bikman firmly believes that red meat, consumed by humans for millennia, is an essential and nutrient-dense food that does not justify modern fears of cancer risk.

The following citations represent the references Dr. Bikman highlighted to discuss the nuanced relationship between red meat consumption and cancer risk.

• The Journal of the American Medical Association (JAMA)

  • Study Title: Meat Intake and Mortality: A Prospective Study of Over Half a Million People (2009)
  • Key Findings: This study suggested a modest increase in total mortality, cancer mortality, and cardiovascular mortality associated with red meat intake.

• American Journal of Epidemiology

  • Study Title: Dietary Fat and Fatty Acids and Risk of Colorectal Cancer in Women (2004)
  • Key Findings: This study found an inverse relationship between dietary fat/fatty acids and colorectal cancer risk in women.

• British Journal of Cancer

  • Study Title: A Cohort Study of Dietary Iron and Heme Iron Intake and Risk of Colorectal Cancer in Women (2007)
  • Key Findings: Women consuming the most red meat (as a source of heme iron) had the lowest colorectal cancer risk.

• Annals of Internal Medicine

  • Studies Discussed in One Issue (2019):
    a. The Effect of Lower vs. Higher Red Meat Intake on Cardiometabolic and Cancer Outcomes
    b. Reduction of Red and Processed Meat Intake and Cancer Mortality and Incidence
    c. Patterns of Red and Processed Meat Consumption and Risk for Cardiometabolic and Cancer Outcomes
  • Key Findings: These studies concluded that evidence linking red meat to cancer is of low to very low certainty, with effects being small or statistically insignificant.

• Obesity Reviews

  • Study Title: Red Meat and Colorectal Cancer: A Critical Summary of Prospective Epidemiologic Studies (2011)
  • Key Findings: Current evidence is insufficient to support a positive association between red meat and colorectal cancer.

• British Medical Journal (BMJ) – Heart

  • Study Title: Overestimation of the Effects of Adherence on Outcomes: A Case Study in Healthy User Bias
  • Key Findings: This study discussed healthy user bias and how it can distort correlational studies on diet and health outcomes.

• Journal of Cancer

  • Study Title: Trimethylamine N-Oxide (TMAO) as One Hypothetical Link for the Relationship Between Intestinal Microbiota and Cancer (2019)
  • Key Findings: TMAO, derived from components like L-carnitine in red meat, was hypothesized as a potential link to cancer risk mediated by gut microbiota.

• Advanced Glycation End Products (AGEs)

  • Study Title: The Role of Advanced Glycation End Products in Carcinogenesis and Their Therapeutic Implications (2019)
  • Key Findings: Discussed the potential of high AGEs, often formed during cooking, as a factor in cancer development.