Efficacy of a Probiotic Formulation (Lacticaseibacillus Rhamnosus - Limosilactobacillus Fermentum) on Gastrointestinal Symptoms in Adults With Lactose Intolerance and Methanogenic Intestinal Overgrowth

Lactose intolerance (LI) is a syndrome associated with specific symptoms, including abdominal bloating and pain, nausea, flatulence, borborygmi, and diarrhea following the consumption of foods containing lactose, a disaccharide that is hydrolyzed in the intestine by the enzyme lactase (β-D-galactosidase). However, when there is enzymatic inefficiency or deficiency, malabsorption of the carbohydrate occurs; once present in the large intestine, it is fermented by microorganisms that mediate the production of hydrogen gas (H₂), carbon dioxide (CO₂), methane (CH₄), and short-chain fatty acids. Epidemiological data indicate a global prevalence of LI ranging from 65% to 70%; consequently, a significant percentage of people have difficulty consuming dairy products and must follow a treatment regimen that involves reducing or avoiding their intake. Consequently, the search for tools to manage LI has sparked interest in effective probiotic species capable of acting as an enzymatic source of β-galactosidase in the gastrointestinal tract. In particular, certain strains with β-galactosidase activity can contribute to lactose hydrolysis and symptom relief, such as: Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus reuteri, Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium, and Saccharomyces boulardii. Previous clinical trials have noted its use in treating gastrointestinal symptoms and the amount of exhaled H₂ measured by the Hydrogen Breath Test (HBT) before and after probiotic interventions.

However, given that the gut microbiota comprises bacterial communities, viruses, fungi, archaea, and protozoa, it is important to consider its influence on the pathogenesis of certain conditions; in particular, intestinal methanogenic overgrowth (IMO) may have clinical relevance as it is associated with functional gastrointestinal disorders where symptoms may overlap with those of other conditions. It has been suggested that IL may be related to the presence of Small Intestinal Bacterial Overgrowth (SIBO) and share symptoms, since SIBO reduces lactose absorption due to abnormal villus function and the destruction of enzymes in the intestinal mucosa, leading to positive IL cases being secondary to SIBO. Additionally, it has been reported that approximately 30% of SIBO cases present with concomitant IMO. However, the therapeutic targets for IMO include antibiotic administration, dietary modifications, and, it is speculated, the use of probiotics, for which there is limited evidence. Therefore, while it is possible to consider the role of probiotics in modulating the gastrointestinal symptoms associated with IL and IMO, the clinical results of probiotic supplementation are inconclusive. For this reason, we conducted a preliminary pilot efficacy study using the strains Limosilactobacillus fermentum L-33 and Lacticaseibacillus rhamnosus L-134, both isolated from a gastric biopsy and possessing high lactase-producing capacity.

Therefore, the objective of this pilot study was to analyze the efficacy of a capsule formulation containing both probiotics and its effect on gastrointestinal symptoms in adults with lactose intolerance and intestinal methanogenic overgrowth.

Research hypothesis: daily administration, for 12 weeks, of a probiotic formulation with the strains Lacticaseibacillus rhamnosus L-134 and Limosilactobacillus fermentum L-33 with β-galactosidase activity decreases the quantity of exhaled H2 measured through the intervention of HBT and the presentation of gastrointestinal symptoms in adults.

Material and methods: The group of participants was made up of 22 adults of both genders (13 women and 9 men). The group underwent an HBT at the beginning of the intervention to confirm the diagnosis of LI and perform the initial H2 measurement. 12 participants (6 women and 6 men) received a diagnosis of LI. 2 participants tested positive for LI and IMO (2 men) and 8 participants were diagnosed with IMO (7 women and 1 man).