The gut microbiota generate diverse bioactive compounds that can potentially affect host physiology. During bouts of malnutrition, the microbiota also become depleted, which can compound the harm to the host, especially in childhood. Cheng et al. have identified an organism producing a suite of metabolites that associate with increased weight of recovering malnourished Bangladeshi children on a designed diet; Faecalibacterium prausnitzii is abundant in the guts of children on this diet. This bacterial strain has an analog of a bidirectional fatty acid amide hydrolase with broad substrate specificity that hydrolyzes N-acylethanolamines and synthesizes N-acylamides into active products at the gut mucosa. This versatility indicates a specific bacterial capacity to regulate signaling in the human gut, affecting immunity, appetite, and growth. —Caroline Ash
