Objectives: Lactose intolerance (LI) is a condition characterized by absent or strongly decreased levels of intestinal lactase. This is a key enzyme for the lactose hydrolysis to monosaccharides, glucose, and galactose. Colonic bacteria metabolize the unabsorbed lactose, producing short-chain fatty acids and gas and resulting in nausea, bloating and diarrhea. Probiotics are gaining interest as a potential compensation for lactase insufficiency, particularly the predominant ones in the gastrointestinal microbiota, such as Bifidobacterium and Lactobacillus. Among the latter species, medical attention is nowadays focusing on a gram-positive strain, Lactobacillus Reuteri, which is able to stabilize intestinal permeability and to reduce flatulence, diarrhea and nausea. The aim of this review is to collect and summarize the current evidence concerning the beneficial effects of L. Reuteri in the treatment of LI.

Materials and Methods: We conducted a thorough search on PubMed concerning evidence spanning from 2011 to 2021.

Results: Lactobacillus Reuteri has been demonstrated to stabilize intestinal permeability and to be effective in attenuating clinical signs and symptoms of LI. In particular, one study shows that Lactobacillus reuteri treatment significantly improves lactose digestion with respect to placebo; however, its effects were lower than those observed with tilactase supplementation.

Conclusions: Although literature is scant on this matter, Lactobacillus Reuteri seems to meet the requirements to be safely used in managing symptoms of lactose intolerance.