Spotlight: Lactobacillus reuteri: Good for Oral, Intestinal and Heart health

In a recent article on infant probiotics, strains of Lactobacillus reuteri were found to be very effective at treating infant colic. This sparked my curiosity to find out more about L. reuteri, and its ability to help treat other diseases. Turns out that this species can help other problems including cavities and high cholesterol. See below.


Lactobacillus reuteri was already discovered more than one hundred years ago, but Gerhard Reuter, for whom the species is named, didn’t formally classify it as its own species until the 1960s. It turned out to be a widespread species and is found in the intestines and fecal matter of a variety of animals including humans. Not surprisingly, given its ability to reside in a variety of organisms, it’s also abundant in our food1.

Early on scientists discovered that L. reuteri could produce an antimicrobial substance, which they named “reuterin.” Reuterin could inhibit the growth of some bacteria, yeasts, fungi and protozoa, but was found to be less effective on native microbial residents of the gut. This gave L. reuteri an intrinsic probiotic effect allowing it to protect other intestinal microflora from “unfriendly” invaders and limiting populations of Escherichia coli1.

Strains of Lactobacillus reuteri

During my research, I discovered that there were actually only a limited number of strains being investigated, but they had many different names. The most commonly used L. reuteri strain was ATCC 55730. This strain is readily available for study at the American Type Culture Collection (ATCC). As you may have guessed, ATCC 55730 is actually the company’s designation number and is not the real strain name. The real strain designation is actually SD21122.  However, I will use ATCC 55730 in the sections below.

The second most commonly tested type is L. reuteri DSM 17938. This strain is the daughter strain of ATCC 55730 and has the same properties as ATCC 55730. It is also known under the trade strain name, “ProTectis3.”  It was created and patented by the company BioGaia. In this article, it will be referred to as DSM 17938.

Lactobacillus reuteri ATCC PTA 5289 is another BioGaia patented strain. An examination of BioGaia patents revealed that its true strain name is FJ1. Together with BioGaia’s DSM 17938, it makes the trade strain known as “ProDentis3.”

Lactobacillus reuteri NCIMB 30242 was originally isolated from a pig. This has the trade name of L. reuteri Cardioviva™ and is currently deposited in the National Collection of Industrial and Food Bacteria international culture collection under the number NCIMB 30242. The company Micropharma Ltd. is the holder of the patent4.


All strains of L. reuteri are very well tolerated. The strain ATC 55730 was found to be safe for babies when provided in formula6 and was safe in HIV patients7. DSM 17938 is safe for adults when given daily for 2 months at a concentration of 500 million per day8. No adverse events were recorded when DSM 17938 was provided to children for diarrhea9 or when given to infants for eight weeks10. The strain NCIMB 30242 was safe in adults at a concentration of 50 billion per day for six weeks11. This was also confirmed in a second study12.

Effectiveness in Clinical Trials

Oral Health

The prevention of cavities using probiotics appears to be a possibility, and the company BioGaia is currently pursuing this concept. Initial studies in 2004 and 2006 demonstrated that unspecified strains of L. reuteri could help oral conditions. Consuming yogurt with L. reuteri could decrease oral Streptococcus mutans, which produces acid that breaks down teeth13, and supplementation decreased gingivitis scores and reduced plaque in those with moderate to severe gingivitis5.

In support of these initial studies, a trial using the specific strain ATCC 55730, administered using a straw or lozenge, reduced the levels of salivary S. mutans in young adults14, and BioGaia’s ProDentis appeared to lower periodontal pathogens after one month of supplementation15. However, a study with a more rigorous protocol using mouth sterilization techniques found that ProDentis probiotic lozenges couldn’t inhibit the regrowth of S. mutans16.

In a more clinical setting, BioGaia’s ProDentis had better results. It was found to be effective in improving parameters associated with periodontitis when given for 30 days17.


An early study performed in 1997 indicated that L. reuteri could treat acute viral diarrhea in children18. Later studies using the research strain ATCC 55730 found that supplemented babies had shorter episodes of diarrhea and were, in general, fitter19. This strain also had success reducing the incidence of antibiotic-associated diarrhea in hospitalized patients when given for four weeks20.

BioGaia’s strain DSM 17938 (the daughter strain of ATCC 55730) was found to prevent diarrhea in malnourished Indonesian children21. It also was shown to combat acute diarrhea in children when combined with rehydration therapy in a study performed in 20129. However, DSM 17938 did not prevent diarrhea that developed within three days of admittance to a hospital22 suggesting that short-term treatment is not enough for good prevention of diarrheal infections.


There is some evidence of a positive effect on constipation. The strain DSM 17938 had a positive effect on bowel frequency in infants with chronic constipation10.

Stomach Ulcers

Stomach ulcers are often caused by the pathogen Helicobacter pylori. Probiotic treatment with the strain ATCC 55730 was found to reduce the H. pylori load and dyspeptic symptoms in patients; however, it did not improve the eradication rates of subsequent antibiotic treatment23. Another study, using a breath test to determine the H. pylori burden, confirmed the ability of ATCC 55730 to inhibit this pathogenic bacteria in patients24.

Ulcerative Colitis

One study used ATCC 55730 in an enema to treat children with ulcerative colitis active in the distal region (near the rectum). It was found to improve clinical and immunological parameters25.

High Cholesterol

Lactobacillus reuteri NCIMB 30242 capsules administered to patients with hypercholesterolemia showed positive results in two studies. The treatment significantly lowered cholesterol compared to placebo group26, 27.

General Health

In an interesting study aimed to look at workplace health, daily supplementation with ATCC 55730 could prevent sickness in the workplace. Workers received a probiotic or a placebo, and sick-leave was measured. The frequency of sick days was sharply reduced in those getting ATCC 5573028.

Obtaining the Right Lactobacillus reuteri Strains

The strain ATCC 55730 is a research strain. However, DSM 17938 is a related strain with the same properties. DSM 17938 is found in the ProTectis strain products of BioGaia (including an unique straw product). This strain is also found in some Nestlé baby formulas found outside of the US. The Gerber Soothe Colic drops also carries the ProTectis (DSM 17938) strain. The Italian company Probiotical also has some rights to the DSM 17938 strain, but at this time, they do not seem to have any clear product.

If you are interested in oral benefits, the ProDentis strain product of BioGaia have two strains: DSM 17938 and PTA 5289. Together with GUM, they make a probiotic lozenge to help teeth and gums.

The strain used for the cholesterol studies is NCIMB 30242. This found in the Cardioviva™ probiotic from Micropharma.


Lactobacillus reuteri strains appear very promising for a variety of conditions. Also seeing that there are limited numbers of strains studied and some are the same (ATCC 55730 and DSM 17938), L. reuteri supplementation can be expected to have multiple proven benefits including gastrointestinal health, oral health and general vitality. And considering its excellent safety record, it’s probably worth a try for mild health conditions.

For those with serious health conditions like ulcerative colitis, it’s still wise to see a doctor. As with any attempt to use probiotics to improve health, it’s important to realize that clinical studies can sometimes be misleading. Just because a study states a particular significant effect does not mean that every participant saw improvements.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment.


1.         Lactobacillus reuteri., Accessed Date Accessed.

2.         Lactobacillus reuteri, SD2112 (ATCC® 55730™)., Accessed Date Accessed.

3.         Questions and answers. – prodentis, Accessed Date Accessed.

4.         Lactobacillus reuteri NCIMB 30242 GRAS Notice., 2011, Accessed Date Accessed 2011 Accessed.

5.         Krasse P, Carlsson B, Dahl C, Paulsson A, Nilsson A, Sinkiewicz G. Decreased gum bleeding and reduced gingivitis by the probiotic Lactobacillus reuteri. Swed Dent J 2006; 30(2): 55-60.

6.         Weizman Z, Alsheikh A. Safety and tolerance of a probiotic formula in early infancy comparing two probiotic agents: a pilot study. J Am Coll Nutr 2006; 25(5): 415-419.

7.         Wolf BW, Wheeler KB, Ataya DG, Garleb KA. Safety and tolerance of Lactobacillus reuteri supplementation to a population infected with the human immunodeficiency virus. Food Chem Toxicol 1998; 36(12): 1085-1094

8.         Mangalat N, Liu Y, Fatheree NY, Ferris MJ, Van Arsdall MR, Chen Z et al. Safety and tolerability of Lactobacillus reuteri DSM 17938 and effects on biomarkers in healthy adults: results from a randomized masked trial. PLoS One 2012; 7(9): e43910.

9.         Francavilla R, Lionetti E, Castellaneta S, Ciruzzi F, Indrio F, Masciale A et al. Randomised clinical trial: Lactobacillus reuteri DSM 17938 vs. placebo in children with acute diarrhoea–a double-blind study. Aliment Pharmacol Ther 2012; 36(4): 363-369.

10.       Coccorullo P, Strisciuglio C, Martinelli M, Miele E, Greco L, Staiano A. Lactobacillus reuteri (DSM 17938) in infants with functional chronic constipation: a double-blind, randomized, placebo-controlled study. J Pediatr 2010; 157(4): 598-602.

11.       Jones ML, Martoni CJ, Tamber S, Parent M, Prakash S. Evaluation of safety and tolerance of microencapsulated Lactobacillus reuteri NCIMB 30242 in a yogurt formulation: a randomized, placebo-controlled, double-blind study. Food Chem Toxicol 2012; 50(6): 2216-2223.

12.       Jones ML, Martoni CJ, Di Pietro E, Simon RR, Prakash S. Evaluation of clinical safety and tolerance of a Lactobacillus reuteri NCIMB 30242 supplement capsule: a randomized control trial. Regul Toxicol Pharmacol 2012; 63(2): 313-320.

13.       Nikawa H, Makihira S, Fukushima H, Nishimura H, Ozaki Y, Ishida K et al. Lactobacillus reuteri in bovine milk fermented decreases the oral carriage of mutans streptococci. Int J Food Microbiol 2004; 95(2): 219-223.

14.       Caglar E, Cildir SK, Ergeneli S, Sandalli N, Twetman S. Salivary mutans streptococci and lactobacilli levels after ingestion of the probiotic bacterium Lactobacillus reuteri ATCC 55730 by straws or tablets. Acta Odontol Scand 2006; 64(5): 314-318.

15.       Iniesta M, Herrera D, Montero E, Zurbriggen M, Matos AR, Marin MJ et al. Probiotic effects of orally administered Lactobacillus reuteri-containing tablets on the subgingival and salivary microbiota in patients with gingivitis. A randomized clinical trial. J Clin Periodontol 2012; 39(8): 736-744.

16.       Keller MK, Hasslof P, Dahlen G, Stecksen-Blicks C, Twetman S. Probiotic supplements (Lactobacillus reuteri DSM 17938 and ATCC PTA 5289) do not affect regrowth of mutans streptococci after full-mouth disinfection with chlorhexidine: a randomized controlled multicenter trial. Caries Res 2012; 46(2): 140-146.

17.       Vicario M, Santos A, Violant D, Nart J, Giner L. Clinical changes in periodontal subjects with the probiotic Lactobacillus reuteri Prodentis: a preliminary randomized clinical trial. Acta Odontol Scand 2013; 71(3-4): 813-819.

18.       Shornikova AV, Casas IA, Isolauri E, Mykkanen H, Vesikari T. Lactobacillus reuteri as a therapeutic agent in acute diarrhea in young children. J Pediatr Gastroenterol Nutr 1997; 24(4): 399-404.

19.       Weizman Z, Asli G, Alsheikh A. Effect of a probiotic infant formula on infections in child care centers: comparison of two probiotic agents. Pediatrics 2005; 115(1): 5-9.

20.       Cimperman L, Bayless G, Best K, Diligente A, Mordarski B, Oster M et al. A randomized, double-blind, placebo-controlled pilot study of Lactobacillus reuteri ATCC 55730 for the prevention of antibiotic-associated diarrhea in hospitalized adults. J Clin Gastroenterol 2011; 45(9): 785-789.

21.       Agustina R, Kok FJ, van de Rest O, Fahmida U, Firmansyah A, Lukito W et al. Randomized trial of probiotics and calcium on diarrhea and respiratory tract infections in Indonesian children. Pediatrics 2012; 129(5): e1155-1164.

22.       Wanke M, Szajewska H. Lack of an effect of Lactobacillus reuteri DSM 17938 in preventing nosocomial diarrhea in children: a randomized, double-blind, placebo-controlled trial. J Pediatr 2012; 161(1): 40-43 e41.

23.       Francavilla R, Lionetti E, Castellaneta SP, Magista AM, Maurogiovanni G, Bucci N et al. Inhibition of Helicobacter pylori infection in humans by Lactobacillus reuteri ATCC 55730 and effect on eradication therapy: a pilot study. Helicobacter 2008; 13(2): 127-134.

24.       Imase K, Tanaka A, Tokunaga K, Sugano H, Ishida H, Takahashi S. Lactobacillus reuteri tablets suppress Helicobacter pylori infection–a double-blind randomised placebo-controlled cross-over clinical study. Kansenshogaku Zasshi 2007; 81(4): 387-393.

25.       Oliva S, Di Nardo G, Ferrari F, Mallardo S, Rossi P, Patrizi G et al. Randomised clinical trial: the effectiveness of Lactobacillus reuteri ATCC 55730 rectal enema in children with active distal ulcerative colitis. Aliment Pharmacol Ther 2012; 35(3): 327-334.

26.       Jones ML, Martoni CJ, Prakash S. Cholesterol lowering and inhibition of sterol absorption by Lactobacillus reuteri NCIMB 30242: a randomized controlled trial. Eur J Clin Nutr 2012; 66(11): 1234-1241.

27.       Jones ML, Martoni CJ, Parent M, Prakash S. Cholesterol-lowering efficacy of a microencapsulated bile salt hydrolase-active Lactobacillus reuteri NCIMB 30242 yoghurt formulation in hypercholesterolaemic adults. Br J Nutr 2012; 107(10): 1505-1513.

28.       Tubelius P, Stan V, Zachrisson A. Increasing work-place healthiness with the probiotic Lactobacillus reuteri: a randomised, double-blind placebo-controlled study. Environ Health 2005; 4: 25.