The use of probiotics and prebiotics can enable the ingestion of dairy products by lactose intolerant individuals

To investigate, through a systematic review, the efficiency of the clinical application of probiotic and prebiotic supplements in reducing the symptoms of lactose intolerance (LI).This systematic review was conducted without limits for publication time and followed the PRISMA 2020 guidelines. The study was registered at the PROSPERO platform (CRD42022295691). The inclusion criteria were: studies addressing the issue of LI associated with the use of probiotics and prebiotics of any nature; studies performed with adults; randomized, placebo-controlled trials; and open access scientific articles, theses, or dissertations. The studies were retrieved from the following databases: SciELO, PubMed, LILACS, ScienceDirect, and gray literature, with no restrictions imposed regarding the years of publication of the investigations. To document the risk of bias, the RoB 2.0 tool was adopted, and to assess the certainty of the evidence, the GRADE tool was used.A total of 830 studies were found; however, after applying the inclusion and exclusion criteria, only five studies remained. Two studies used the prebiotic GOS (RP-G28) for the treatment of LI and, together, included 462 subjects. The results of these studies showed improvement of LI symptoms during treatment phase and up to 30 days after cessation of GOS use (RP-G28). Three studies used the probiotics Bifidobacterium bifidum 900791, Limosilactobacillus reuteri DSM 17938 (Lactobacillus reuteri), and Lactobacillus acidophilus DDS-1 to evaluate their effects on LI and comprised 117 subjects. The results showed that B. bifidum 900791 did not significantly improve LI symptoms, and only Limosilactobacillus reuteri DSM 17938 showed significant improvement in symptoms and in reduction of expired hydrogen, while Lactobacillus acidophilus DDS-1 showed significant improvement for LI symptoms. The risk of bias for studies on probiotics suggested concerns in all studies, whereas the risk of bias was low in investigations evaluating prebiotics, with only one study classified as concerning. The certainty of evidence was high for the studies using the GOS (RP-G28) prebiotic and low for the probiotics. Pooling for meta-analysis could not be performed due to the lack of similar probiotic strains or lack of common outcomes.In summary, the probiotics Limosilactobacillus reuteri DSM 17938 and Lactobacillus acidophilus DDS-1 showed the best results in the management of LI symptoms. The prebiotic GOS (RP-G28) appeared to be more efficient in reducing post-treatment symptoms. However, it is noteworthy that evidence regarding the use of probiotics for the management of LI is considerably scarce; as for prebiotics, data are limited. Studies adopting robust methodologies, especially regarding the complete reporting of data, are therefore warranted.