Limosilactobacillus reuteri is a naturally occurring species of lactic acid bacteria that is widely recognized for its probiotic properties. The species, formerly known as Lactobacillus reuteri, was reclassified into the genus Limosilactobacillus in 2020 following advancements in biomolecular research. This microbe is a gram-positive, rod-shaped bacterium that is found in the gastrointestinal tracts of various mammals, including humans. L. reuteri is considered a facultative anaerobe, meaning it can survive in environments with or without oxygen, which allows it to thrive in diverse ecological niches throughout the body, such as the oral cavity, gut, and skin.
The Unique Action of Limosilactobacillus reuteri
The distinguishing feature of L. reuteri among probiotics is its capacity to produce a powerful, broad-spectrum antimicrobial compound called reuterin. Reuterin is synthesized during the metabolism of glycerol under anaerobic conditions. This production provides L. reuteri with a competitive advantage in the gut microbiome.
Reuterin exhibits activity against a wide range of harmful microorganisms, targeting Gram-positive and Gram-negative bacteria, yeasts, fungi, and some protozoa. The mechanism by which reuterin inhibits pathogens involves interfering with their cellular processes, such as compromising DNA synthesis. This unique metabolite production allows L. reuteri to directly modulate the microbial landscape of the gut, suppressing the growth of potential invaders.
Supporting Digestive and Infant Health
One of the most evidence-based applications of L. reuteri is in improving digestive comfort, particularly in infants. Clinical trials have demonstrated that supplementation with specific strains, such as L. reuteri DSM 17938, significantly reduces crying time in breastfed infants suffering from infantile colic. The reduction in crying is linked to the probiotic’s ability to modulate the gut microbiota composition, potentially reducing gas production and intestinal inflammation.
The species also plays a supportive role in managing acute infectious diarrhea, particularly in young children. When administered as an adjunct to rehydration therapy, L. reuteri has been shown to slightly reduce the duration of diarrhea, often by 32 to 33 hours. This effect is attributed to its general anti-inflammatory properties within the gut.
L. reuteri contributes to the integrity of the intestinal lining. Certain strains enhance the function of the intestinal barrier by strengthening the tight junctions between intestinal cells. A stronger intestinal barrier helps prevent the passage of toxins and pathogens from the gut lumen into the bloodstream, supporting overall gastrointestinal tolerance.
Roles Beyond the Gut
While its primary effects are observed in the digestive tract, the influence of L. reuteri extends systemically through immune system modulation. The bacterium interacts with host immune cells and regulates the body’s inflammatory response by influencing signaling molecules called cytokines, leading to antibacterial and anti-inflammatory effects.
This modulatory function holds promise for conditions outside the gut, including oral health. L. reuteri strains can inhibit the colonization of bacteria that cause cavities, such as Streptococcus mutans, and those linked to gum disease. By competing for adhesion sites, the probiotic helps maintain a beneficial microbial balance in the mouth.
Emerging research suggests potential links between L. reuteri and other body systems. Certain strains influence bone metabolism in animal models, suggesting a possible role in reducing bone loss. Furthermore, the gut-skin axis indicates a connection between the gut microbiome and skin health, with L. reuteri being investigated for its potential to alleviate symptoms in conditions like atopic dermatitis.
Supplementation and Safety Profile
Limosilactobacillus reuteri supplements are widely accessible and come in several forms to suit different populations, particularly infants. Common delivery formats include liquid drops, chewable tablets, and capsules. The effective dose varies depending on the specific strain and the condition being targeted, often ranging from \(10^8\) to \(10^{10}\) Colony Forming Units (CFU) per day.
The species has a strong safety profile and is generally regarded as safe for both children and adults, with some strains having received Generally Recognized As Safe (GRAS) status. Side effects are infrequent and usually mild, occasionally including temporary digestive discomfort such as increased gas or bloating as the gut adjusts.
The beneficial effects of probiotics are often strain-specific; the positive results observed with one strain, such as L. reuteri DSM 17938, may not apply to all others. Taking the supplement at least two hours before or after antibiotics is recommended to ensure the viability of the probiotic bacteria.