Changes in lifestyle, particularly those associated with industrialization and diet, can substantially affect the gut microbiome, which leads to reduced microbial diversity and loss of beneficial immunomodulatory microorganisms. A Western diet — high in saturated fat, ultra-processed food and animal protein, while low in fibres, fruits and vegetables — has been consistently associated with a higher risk of non-communicable diseases and reduced gut microbiome diversity. It is unclear whether restoring the industrialized gut microbiome through increased dietary fibre intake or reintroduction of beneficial microorganisms provides real benefits to human health. In a recent study, Li et al. investigated in a randomized clinical feeding trial the effects of a microbiome restoration strategy that combines a bacterium nearly absent in industrialized gut microbiomes with a diet with non-industrialized features.

The restore diet was safe and well tolerated; it reduced gut transit time, likely due to the higher fibre intake, and increased gastrointestinal symptoms (flatulence, abdominal tension). L. reuteri had no detectable effects, and no serious adverse events were detected related to the intervention.