Resistant Starch and Red Meat

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.

 

From

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

Mark Sisson on Red Meat Scares

Loren Cordain on 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.

Or:

“Resistant Starch May Reduce Colon Cancer Risk From Red Meat”

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.”
 This paper goes on to say:
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.
And therein lies a big part of the problem!  A “side of potato salad or beans” is a good start, but will not come close to matching the amounts used in these studies, which generally is in the 20-40g/day range. Whether you eat too much red meat or not, a diet high in fiber and especially resistant starch will ensure your colon is a healthy place. Potato salad and beans are a great start.  Then there’s green bananas, popcorn, oatmeal, and if you really want to kick it up a notch, raw potato starch and Hi-Maize.

Conclusion

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:

Effects of potato fiber and potato-resistant starch on biomarkers of colonic health in rats fed diets containing red meat.

 Resistant starch prevents colonic DNA damage induced by high dietary cooked red meat or casein in rats.

Dose-dependent reduction of dietary protein-induced colonocyte DNA damage by resistant starch in rats correlates more highly with caecal butyrate than with other short chain fatty acids

 High red meat diets induce greater numbers of colonic DNA double-strand breaks than white meat in rats: attenuation by high-amylose maize starch.

Review article: insights into colonic protein fermentation, its modulation and potential health implications

Role of Red Meat and Resistant Starch in Promutagenic Adduct Formation, MGMT
Repair, Thymic Lymphoma and Intestinal Tumourigenesis in Msh2-Deficient Mice.

Resistant starch prevents colonic DNA damage induced by high dietary cooked red meat or casein in rats.

Inhibition by resistant starch of red meat-induced promutagenic adducts in mouse colon.

Resistant Starches Protect against Colonic DNA Damage and Alter Microbiota and Gene Expression in Rats Fed a Western Diet

Dietary manipulation of oncogenic microRNA expression in human rectal mucosa: a randomized trial.

Colorectal Carcinogenesis: A Cellular Response to Sustained Risk Environment

Primary Prevention of Colorectal Cancer

Colonocyte telomere shortening is greater with dietary red meat than white meat and is attenuated by resistant starch.

Later!

Tim

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