Lactobacillus reuteri inhibits pathogens through the compound reuterin, which also has anti-cancer and immunomodulatory properties; it boosts oral health and lowers cholesterol.
What is L. reuteri?
Lactobacillus reuteri, which is now scientifically reclassified as Limosilactobacillus reuteri, is a gram-positive, lactic-acid-producing probiotic bacterium that is naturally found in the gastrointestinal tract, oral cavity, and breast milk of humans and other mammals.
It was originally isolated in 1962. It is one of the most studied probiotic species due to its resilience in harsh stomach conditions and its ability to temporarily colonise the entire digestive system.
Which foods provide L reuteri?
The truth is that L. reuteri is not reliably or consistently found in food in meaningful, standardized amounts. Its primary natural habitat is the human gut and breast milk.
It is sometimes found in yogurt & kefir (check the label)and traditionally unpasteurised fermented vegetables (sauerkraut, kimchi, fermented cucumbers); certain cheeses (Cheddar, Gruyère, Parmigiano Reggiano) and occasionally sourdough bread, miso, tempeh.
What are its main benefits of L. reuteri?
It produces reuterin, a broad-spectrum antimicrobial compound derived from glycerol fermentation. It thus inhibits harmful bacteria, fungi, and protozoa.
It is one of the few lactic acid bacteria capable of producing vitamin B12 (cobalamin) and folate in the gut.
Supplementation has been shown to strengthen the intestinal barrier, reduce gut leakiness, and improve symptoms of infantile colic, diarrhea, and constipation.
It helps regulate the immune system by reducing pro-inflammatory cytokines.
It may improve metabolic health by lowering cholesterol and supporting glucose homeostasis.
It improves oral health, reduces pathogenic bacteria in the mouth, aiding in the prevention of dental cavities and managing gum disease.
L. reuteri and cancer
L. reuteri has shown cytotoxic and growth-inhibitory effects against various cancers primarily through its metabolite reuterin. It also has immunomodulatory benefits.
Research indicates that L. reuteri is significantly downregulated in the gut microbiomes of patients with colorectal cancer compared to healthy individuals. Reuterin in the healthy gut microbiome suppresses colorectal cancer growth through altering redox balance. (1).
Lactobacillus reuteri exhibits significant chemoprotective and immunomodulatory potential against breast cancer, primarily by stimulating host immune responses and inducing apoptosis in cancer cells (2)
Lactobacillus reuteri and its derivatives have demonstrated potential in treating lymphoma and other cancers through multiple mechanisms.
Research also indicates that reuterin suppresses the proliferation of lymphoma cells, ovarian and CRC cells by inducing apoptosis and increasing intracellular reactive oxygen species. In leukaemia, L. rhamnosus and L reuteri were shown to have effects with ALL (3).
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References
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Reuterin in the healthy gut microbiome suppresses colorectal cancer growth through altering redox balance; Hannah N. Bell et al; Cancer Cell. 2021 Dec 23;40(2):185–200.e6. doi: 10.1016/j.ccell.2021.12.001
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Tumor-related Microbiome in the Breast Microenvironment and Breast Cancer; Na Wang et al; J Cancer 2021; 12(16):4841-4848. doi:10.7150/jca.58986
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Anticancer Activity of Postbiotic Mediators Derived from Lactobacillus Rhamnosus GG and Lactobacillus Reuteri on Acute Lymphoblastic Leukemia Cells; Morteza Banakar et al; Galen Med J. 2023 Aug 19;12:e3096. doi: 10.31661/gmj.v12i.3096