Urban indoor gardening enhances immune regulation and diversifies skin microbiota — A placebo-controlled double-blinded intervention study

Urban Farm DB summary

A one-month randomized, placebo-controlled, double-blind trial had volunteers grow edible plants indoors during winter, when natural exposure to environmental microbiota is low, comparing a microbially diverse growing medium against a visually similar but microbially poor placebo medium. Skin microbiota and seven immune markers were measured at baseline and after one month. The diversity of five bacterial phyla (Bacteroidetes, Planctomycetes, Proteobacteria, Cyanobacteria, Verrucomicrobia) and one class (Bacteroidia) increased on participants' skin in the intervention group, with no change in the placebo group, and the number of nodes and edges in skin-bacteria co-occurrence networks increased roughly three times more in the intervention group. Plasma interleukin-10 rose in the intervention group relative to placebo, with a similar trend for interleukin-17A and the IL-10:IL-17A ratio, while satisfaction and adherence were high in both groups.