Cannabis and Microbiome: A Systematic Review and Meta-Analysis.

BackgroundWith cannabis legalization spreading to more countries for both medicinal and recreational use, grasping its effects on the human body is vital. The endocannabinoid system, governed by natural and external cannabinoid compounds, significantly impacts host metabolism. Working alongside the hosts immunomodulation, it shapes the gut microbiota, yielding benefits for the GI and immune systems. ObjectiveTo assess the link between cannabis treatment and the gut/oral microbiome. MethodsWe extensively searched PubMed, Embase, and Cochrane Librarys CENTRAL until December 9, 2023, for English studies involving adults with clinical abnormalities. Identified studies were analyzed, categorizing by different clinical aspects. Data was then qualitatively and quantitatively synthesized. ResultThe study involved 10 studies encompassing 2511 participants, comprising 2 clinical trials and 8 observational studies. The review provided a range of microbiota by the influence of cannabis usage within different clinical contexts: HIV infection, pain/inflammation, systemic aspergillosis, obesity, cognitive deficits, and oral diseases. Users with anhedonia and HIV infection showed lower -diversity, but those with knee arthritis showed higher -diversity. According to research, 21.4% of MJ cigarette users experienced adverse outcomes; however, these lessened once they stopped smoking. ConclusionThese findings shed light on the complex effects of cannabis use on the human microbiota, underscoring the need for future research on the therapeutic potential of cannabis. This review provides valuable insights to guide future investigations in this field. Registration IDPROSPERO 2022 CRD42022354331 Short SummaryWith the global expansion of cannabis legalization, understanding the effects of cannabis on the human body, particularly among individuals with diverse clinical conditions, is of paramount importance. Through a meticulous systematic review utilizing comprehensive data, our findings uncover that cannabis consumption in adults with varied clinical conditions leads to discernable alterations in the human microbiome. These noteworthy modifications necessitate careful consideration in future investigations exploring the potential beneficial or adverse effects of cannabis treatment on patients.