Probiotic bacteria inhibit cancer

Beneficial bacteria stimulate host immune cells to counteract dietary and genetic predisposition to mammary cancer in mice

Recent studies suggest health benefits including protection from cancer after eating fermented foods such as probiotic yogurt, though the mechanisms are not well understood. Here we tested mechanistic hypotheses using two different animal models: the first model studied development of mammary cancer when eating a Westernized diet, and the second studied animals with a genetic predilection to breast cancer. For the first model, outbred Swiss mice were fed a Westernized chow putting them at increased risk for development of mammary tumors. In this Westernized diet model, mammary carcinogenesis was inhibited by routine exposure to Lactobacillus reuteri ATCC-PTA-6475 in drinking water. The second model was FVB strain erbB2 (HER2) mutant mice, genetically susceptible to mammary tumors mimicking breast cancers in humans, being fed a regular (non-Westernized) chow diet. We found that oral supplement with these purified lactic acid bacteria alone was sufficient to inhibit features of mammary neoplasia in both models. The protective mechanism was determined to be microbially-triggered CD4+CD25+ lymphocytes. When isolated and transplanted into other subjects, these L. reuteri-stimulated lymphocytes were sufficient to convey transplantable anti-cancer protection in the cell recipient animals. These data demonstrate that host immune responses to environmental microbes significantly impact and inhibit cancer progression in distal tissues such as mammary glands, even in genetically susceptible mice. This leads us to conclude that consuming fermentative microbes such as L. reuteri may offer a tractable public health approach to help counteract the accumulated dietary and genetic carcinogenic events integral in the Westernized diet and lifestyle.


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Gary Johnson says December 8, 2017

Great site. I fully agree with most everything you propose for anti-aging.
However, I am a little surprised that you don’t stress gut health more and the consumption of fermented vegetables as a means. Recent research shows that products of lactobacillus Plantarum (sauerkraut) fermentation produce alkyl catechol’s from phenolic acids (i.e. caffeic) normally present in most vegetables (cabbage). Alkyl catechols are a potent activator of NRF2. The organism must produce Phenolic Acid Decarboxylase which most lactobacilli do.
Check it out


    P. D. Mangan says December 8, 2017

    Gary, thank you. I do believe a healthy gut is important, but what I wonder about all of the many studies linking certain species or proportions of gut bacteria to health is correlation vs causation. For example, exercise alone changes composition of gut microbiota, as does dietary change. Furthermore, fiber has been something of a bust as far as health improvement. So from my POV, gut health as a life extension intervention is a bit far down on my list, although I keep an open mind and am willing to be persuaded of its greater importance.

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