Cancer is something almost everyone worries about getting, although the risk of dying of heart disease is significantly greater. Still, the odds of developing cancer goes up with age. It’s frightening to think about but research shows that most cancer isn’t genetic in origin but affected by lifestyle habits. Scientists believe that diet, among other factors, increases the risk of developing certain forms of cancer. In fact, some studies show a link between eating a diet high in red meat, especially processed meat, and enhanced odds of developing colon cancer and other cancers of the digestive tract.
What a New Study Shows about Meat, Dairy, and Cancer Risk
If eating a diet rich in meat and dairy increases the risk of certain forms of cancer, what is the mechanism? Researchers at the Department of Cell Research and Immunology at the Shmunis School of Biomedicine and Cancer Research at Tel Aviv University’s George S. Wise Faculty of Life Sciences made an interesting discovery. Animal foods, including meat and dairy, contain higher levels of a sugar called Neu5Gc. Mammals, particularly pigs, have substantial levels of this sugar in their organs and tissues. Humans do not, but when we consume meat and dairy from mammals, Neu5Gc enters the bloodstream where it triggers an immune response and antibody production to try to fight the foreign invader.
Humans accumulate higher levels of these antibodies over time as they eat meat and dairy. The theory is that the rising antibodies and immune response to the Neug5Gc sugar create ongoing inflammation and tissue damage that increases the risk of cancer. The highest levels of this sugar are in the organs of pigs and cooking meat from mammals increases the amount of this sugar in the meat. Poultry and fish do not contain Neu5Gc.
Is There Science to Support this Link?
For a study, researchers created a list of foods and food products that contain Neu5Gc and looked at the levels of antibodies to Neu5Gc in 120 subjects. They then compared the antibody levels of the subjects to how many foods they ate that are high in Neu5Gc. The study showed subjects who eat a lot of red meat and cheese have higher levels of Neu5Gc antibodies. To extrapolate further, they believe having higher levels of antibodies Neu5Gc may increase the risk of several forms of cancer, particularly colorectal cancer.
In animal studies, mice that eat diets rich in Neu5Gc have higher levels of these antibodies and more systemic inflammation than mice that eat a lower Neu5Gc diet. The mice with higher levels of these antibodies, in studies, were at greater risk of developing cancer of the liver. Also of interest are studies showing eating a diet rich in red meat increases markers of systemic inflammation in the blood. Low-grade inflammation may boost cancer risk by causing cell and tissue damage that leads to mutations that promote cancer growth.
Red Meat is More of a Concern Than Dairy
Red meat has higher levels of Neu5Gc than dairy and the correlation with cancer risk is stronger with red meat and processed meat than with dairy foods. As a whole, there’s little direct evidence linking dairy products with a higher risk of cancer except for prostate cancer. In fact, some research suggests that dairy foods may lower the risk of colon cancer, possibly due to their high calcium content.
Diet and Cancer Risk
More research is needed in humans to confirm that a diet high in meat and dairy increases the risk of cancer due to Neu5Gc. However, experts believe that eating a more diverse diet that contains more plant-based protein is a wise move. Studies show that people who eat a Mediterranean-style diet that emphasizes fish, fruits, vegetables, whole grains, nuts, seeds, and healthy fats, like monounsaturated fats in olive oil have a lower rate of some health problems, including cardiovascular disease, stroke, and cancer. Fruits and vegetables are rich in antioxidants and compounds with anti-inflammatory activity that may offer some protection against malignancies.
Unfortunately, there’s no one diet that we can call an anti-cancer diet, as cancer is a complex disease that scientists don’t completely understand. However, until we know more, eating more non-starchy vegetables, especially cruciferous vegetables, and quantities of fruit is a smart move. Rather than choosing red meat at most meals, consider fatty fish, rich in omega-3s and poultry, but also plant-based sources of protein.
The Bottom Line
Diet isn’t the only factor that affects the risk of getting cancer. Genetics, obesity, and lack of physical activity increase the risk of cancer too. You can’t control your genetics but you can modify your lifestyle factors and get regular screening if you’re at high risk. Make sure you’re not engaging in bad habits, like smoking and excessive alcohol use too, as these factors raise your odds of developing some forms of cancer too, especially cancer of the lungs and digestive tract.
- com. “Researchers discover molecular link between diet and risk of colorectal cancer”
- Salam Bashir, Leopold K. Fezeu, Shani Leviatan Ben-Arye, Sharon Yehuda, Eliran Moshe Reuven, Fabien Szabo de Edelenyi, Imen Fellah-Hebia, Thierry Le Tourneau, Berthe Marie Imbert-Marcille, Emmanuel B. Drouet, Mathilde Touvier, Jean-Christian Roussel, Hai Yu, Xi Chen, Serge Hercberg, Emanuele Cozzi, Jean-Paul Soulillou, Pilar Galan, Vered Padler-Karavani. Association between Neu5Gc carbohydrate and serum antibodies against it provides the molecular link to cancer: French NutriNet-Santé study. BMC Medicine, 2020; 18 (1) DOI: 10.1186/s12916-020-01721-8.
- Suna Ji, Fang Wang, Yue Chen, Changwei Yang, Panwang Zhang, Xuebing Zhang, Frederic A. Troy, Bing Wang. Developmental changes in the level of free and conjugated sialic acids, Neu5Ac, Neu5Gc and KDN in different organs of pig: a LC-MS/MS quantitative analyses. Glycoconjugate Journal, 2016; DOI: 10.1007/s10719-016-9724-9.
- Proceedings of the National Academy of Sciences. 112 (2): 542–7. doi:10.1073/pnas.
- PNAS January 13, 2015 112 (2) 542-547; first published December 29, 2014. https://doi.org/10.1073/pnas.1417508112.
- Esmaillzadeh A, et al. (2007) Dietary patterns and markers of systemic inflammation among Iranian women. J Nutr 137(4):992–998.
- org. “Can milk and dairy products cause cancer?”
- 2019 Sep; 11(9): 2059. Published online 2019 Sep 2. doi: 10.3390/nu11092059.