Interplay between natural environment, human microbiota and immune system: A scoping review of interventions and future perspectives towards allergy prevention

• Published in: The Science of the total environment 2022-05, Vol.821, p.153422-153422, Article 153422
• Main Authors: Tischer, Christina, Kirjavainen, Pirkka, Matterne, Uwe, Tempes, Jana, Willeke, Kristina, Keil, Thomas, Apfelbacher, Christian, Täubel, Martin
• Format: Article
• Language: English
• Subjects: Biodiversity; Human microbiota; Humans; Hypersensitivity - prevention & control; Immune response; Immune System; Intervention; Microbiota; Natural environment; Prevention; Soil
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.153422

Urbanization and biodiversity loss are linked to chronic disorders, in particular allergic diseases. The aim of this scoping review was to provide a synopsis of intervention studies specifically examining the influence of exposure to natural environments on human microbiota as well as immunological markers as suggested interlink between natural environment and the development of allergic diseases. We searched PubMed (MEDLINE®) and all references cited in the included studies following the PRISMA statement guidelines. No restrictions regarding age and sex of study participants, language or publication date were made. The protocol was registered at OSF REGISTRIES (https://osf.io/musgr). After screening, eight intervention studies were included. The interventions reported were mainly of pilot character and various, ranging from nature-related educational programs, biodiversity interventions in day-cares to short-term contact with soil- and sand-preparations. Most of the studied interventions appeared to increase human microbiota richness and diversity in specific taxa groups in the short-time. Immunological markers were assessed in only two studies. In these, their associations with human microbiota richness were pre-dominantly reported. Conclusion: There is some evidence that the so-called biodiversity interventions have the potential to diversify human microbiota, at least over a short period. Adequately powered randomized controlled trials with long term follow-up are required to examine sustainable effects on microbiota and immune system. [Display omitted] •Only few environmental intervention studies of mainly pilot character were identified.•Environmental interventions appear to diversify human microbiota.•Changes in microbiota diversity partly associate with immunoregulatory markers.•Environmental interventions might be translated into allergy preventive approaches.•Adequately powered studies with long-term follow up are needed.