What is L Reuteri?

Lactobacillus reuteri is a gram-negative rod-shaped bacterium that has been found in various foods, especially meat and milk products. It has been isolated from the intestines of many different mammals in the animal kingdom including rodents, pigs, sheep, and chickens, and is one of the most common organisms found in the human gut. It is one of the most numerous organisms in the mammalian gut microbiome. Each type of mammal (rodents, pigs, chickens, people) has its own specific strain of the organism, leading scientists to believe that it is important to gut health of the host.

What Are The Researched Benefits of Taking L reuteri?

• reduce salivary mutans streptococus (causes cavities)
• reduce plaque on teeth
• reduce nausea
• inhibit and suppress H. pylori
• decrease dyspepsia
• reduce flatulence
• reduce diarrhea (rotavirus and non-rotavirus)
• decrease symptoms of IBS
• stimulate the immune system
• reduce colds and influenza
• decrease atopic dermatitis
• reduce IgE eczema in infancy
• inhibit vaginal candidasis
• reduce vagina pH
• reduce infant colic
• stabilize barrier function (reducing intestinal permeability)

The cool thing about L. reuteri is that it produces an antibiotic as a product of its metabolism. It makes a molecule that we now call reuterin that slows the growth of certain harmful bacteria, viruses, yeasts, fungi, and protozoa.^A It makes enough to stop the bad guys but not enough to hurt the good guys. They can eliminate gut invaders without harming other, beneficial bacteria.

Where does it come from?

Even though L. reuteri is normal in humans, not everyone has it in their GI tract. Colonizing the gut with L. reuteri is easy with oral supplementation, although it does not necessarily stay there long-term unless it’s replenished. Again, good sources of L. reuteri are dairy products and meat, items that are avoided by vegans and most vegetarians, so supplements are important. Interestingly, women who take L. reuteri supplements while breast feeding are more likely to transfer these helpful bacteria to their infant.^B

Who can benefit?

Once L. reuteri is in the gut, it begins to work its magic. It is particularly helpful in kids with diarrhea, where it significantly decreases the length of time the child is symptomatic and reduces the severity of the illness. Other studies have shown that giving L. reuteri as prevention of diarrhea works well in children who are exposed to a diarrheal illness.^C These studies were done in relation to a viral diarrhea, so L. reuteri even helps fight viral infections. It seems to work better than most other probiotics in this regard.^D

A more dramatic disease that responds to L. reuteri is necrotizing enterocolitis in premature babies, a dangerous disease with a high mortality rate in these vulnerable children. L. reuteri reduces the occurrence of sepsis and shortens the length of hospital stay.^E

L. reuteri also seems to help in infant colic.^B We don’t really know what causes infantile colic, making babies cry, have cramps, and have bouts of diarrhea, but giving L. reuteri in formula works better than simethicone. Again, we don’t know why but it works and it’s safe.

What about oral health?

The antibiotic effects of L. reuteri are also helpful in promoting oral health. As discussed in our post on probiotics in oral health, the known bad bug in gingivitis and cavities is called Streptococcus mutans. Of all the probiotic bacteria tested against this organism in one study, L. reuteri was the only one that was able to block the growth of S. mutans.^F (Krasse, 2006) And it works without causing any harmful effects on the teeth. This is big news since gingivitis and tooth decay are the most common infectious diseases in the world. Colonization of the mouth was accomplished through L. reuteri-containing toothpastes, rinses, and gum.

More recent research

Some very cool recent research shows that L. reuteri can fight the bad gut pathogen Helicobacter pylori, known the be the cause of stomach ulcers. This is such a tough infection to treat and eliminate, and giving L. reuteri along with the usual triple antibiotic regimen helped eliminate the bacteria and reduce recurrence.^G

The effectiveness of L. reuteri against Clostridium difficile seems to have inspired a new direction in intelligent design of next-generation probiotic supplements. C. difficile is a form of bacterial overgrowth in the colon caused by giving antibiotics too frequently. This is particularly hard to treat since it makes people very sick, is contagious, and keeps coming back. L. reuteri to the rescue! Certain strains, when mixed with glycerol, produced higher levels of reuterin that were enough to fight off C. difficile, leading to a cure and reducing relapses.^F

All in all, giving L. reuteri results in better overall health. People who take it fall ill less often. Children in day care centers where L. reuteri is given stay healthier and are absent fewer days. Adults use fewer sick days. It just helps people feel better and stay healthier.

Where can I get some?

L. reuteri is present in many dairy products, but probiotic supplements are available with higher doses and better predictability.

Full Reference List

1. Axelsson LT, Chung TC, Dobrogosz WJ, Lindgren SE. Production of a broad spectrum antimicrobial substance by Lactobacillus reuteri. Microbial ecology in health and disease. 1989 Jan 1;2(2):131-6.
2. Sung V, D’Amico F, Cabana MD, Chau K, Koren G, Savino F, Szajewska H, Deshpande G, Dupont C, Indrio F, Mentula S. Lactobacillus reuteri to treat infant colic: a meta-analysis. Pediatrics. 2018 Jan 1;141(1):e20171811.
3. Urbańska M, Gieruszczak‐Białek D, Szajewska H. Systematic review with meta‐analysis: Lactobacillus reuteri DSM 17938 for diarrhoeal diseases in children. Alimentary pharmacology & therapeutics. 2016 May;43(10):1025-34.
4. Shornikova AV, Casas IA, Mykkänen H, Salo E, Vesikari T. Bacteriotherapy with Lactobacillus reuteri in rotavirus gastroenteritis. The Pediatric infectious disease journal. 1997 Dec 1;16(12):1103-7.
5. Athalye‐Jape G, Rao S, Patole S. Lactobacillus reuteri DSM 17938 as a probiotic for preterm neonates: a strain‐specific systematic review. Journal of parenteral and enteral nutrition. 2016 Aug;40(6):783-94.
6. Krasse P, Carlsson B, Dahl C, Paulsson A, Nilsson A, Sinkiewicz G. Decreased gum bleeding and reduced gingivitis by the probiotic Lactobacillus reuteri. Swedish dental journal. 2006;30(2):55-60.
7. Dore MP, Bibbò S, Loria M, Salis R, Manca A, Pes GM, Graham DY. Twice‐a‐day PPI, tetracycline, metronidazole quadruple therapy with Pylera® or Lactobacillus reuteri for treatment naïve or for retreatment of Helicobacter pylori. Two randomized pilot studies. Helicobacter. 2019 Sep 9:e12659.
8. Spinler JK, Auchtung J, Brown A, Boonma P, Oezguen N, Ross CL, Luna RA, Runge J, Versalovic J, Peniche A, Dann SM. Next-generation probiotics targeting Clostridium difficile through precursor-directed antimicrobial biosynthesis. Infection and immunity. 2017 Oct 1;85(10):e00303-17.

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