The Paleo Community is once again backed into a corner, defending “meat.” The World Health Organization recently released a report that says:
Overall, the Working Group classified consumption of processed meat as “carcinogenic to humans” (Group 1) on the basis of sufficient evidence for colorectal cancer. Additionally, a positive association with the consumption of processed meat was found for stomach cancer. The Working Group classified consumption of red meat as “probably carcinogenic to humans” (Group 2A). In making this evaluation, the Working Group took into consideration all the relevant data, including the substantial epidemiological data showing a positive association between consumption of red meat and colorectal cancer and the strong mechanistic evidence. Consumption of red meat was also positively associated with pancreatic and with prostate cancer.
According to the World Health Organization: Processed meats cause cancer; Cooked red meat probably causes cancer.
A diet high in resistant starch has been shown to overcome the cancer-causing effects of meat.
Do a PubMed search for “red meat and cancer” and you’ll get over 1000 hits, that all say, essentially, the same thing. For years, “Paleo” has been batting these papers down one at a time:
Chris Kresser on the Red Meat Scares
But possibly, there is a lesson to be learned in these decades of research that shows a connection between red meat and cancer.
What about this unique thought?:
Addition of RS to the diet abolished the increase in DNA damage and the loss of colonic mucus thickness induced by either high protein diet. Cecal and fecal short chain fatty acid pools were also increased by inclusion of RS in the diet. Because DNA damage is an early step in the initiation of cancer, these findings suggest that increased DNA damage due to high dietary protein as cooked red meat or casein could increase colorectal cancer risk but inclusion of resistant starch in the diet could significantly reduce that risk.
Now do a PubMed search for “Red Meat and Resistant Starch and Cancer.” You’ll get 15 hits, most from just the last couple years.
The most recent, from 2015, was a look at special “butyrylated RS” a special blend of butyrate and Hi-Maize, “Butyrylated starch intake can prevent red meat-induced O6-methyl-2-deoxyguanosine adducts in human rectal tissue: a randomised clinical trial.”
Epidemiological studies have identified increased colorectal cancer (CRC) risk with high red meat (HRM) intakes, whereas dietary fibre intake appears to be protective.
In the present study, we examined whether a HRM diet increased rectal O(6)-methyl-2-deoxyguanosine (O(6)MeG) adduct levels in healthy human subjects, and whether butyrylated high-amylose maize starch (HAMSB) was protective.
A diet high in red meat increases risk of colon cancer. But eating resistant starch—a carbohydrate that acts like fiber—may reduce that risk, according to a study in August’s Cancer Prevention Research.“Red meat and resistant starch have opposite effects on the colorectal cancer–promoting microRNAs,” said first author Karen
Humphreys, Ph.D., a research associate at the Flinders Centre for Innovation in Cancer at Australia’s Flinders University. “This finding supports consumption of resistant starch as a means of reducing the risk.”
The Humphreys study, therefore, is most welcome: “For the red meat lover,” she said, “resistant starch might be an option.” So if you’re going to eat a steak, you might want to order a side of potato salad or beans.
It all makes perfect sense, high meat consumption in our fiberless world causes problems. The WHO report was most critical of “preserved” meats, such as sausages and bacon, and perhaps, we simply don’t need to eat lots of these foods. Even red meat has enough evidence stacked against it that it makes me want to cut back a bit. But I do not feel the need to give up meats, even preserved meats, in light of my high fiber diet. Further reading on RS and red meat: