Food

The gut microbiome is a transducer of the health effects of many food ingredients because of its ability to convert them into health-impacting compounds. Plant-forward diets and plant ingredients are recognized as health promoting, with recent added impetus provided by the drive to provide consumers with more sustainable protein sources than meat. Soy-based foods are good protein sources, and they contain a variety of other ingredients such as fibre that can impact the microbiome. This review explores the health benefits reported for soy-containing foods and the role of microbiome involvement in health effects. It describes the bi-directional relationship between dietary soy and the human gut microbiome whereby microbial metabolism transforms soy-derived compounds into bioactive forms that influence host physiology, while soy consumption shapes gut microbiota composition and activity. Factors modulating the health effects of soy such as fermentation, bioavailability, and consumers’ individual microbiome configurations are discussed. Current research limitations, including inconsistent methodologies and a lack of longitudinal dietary intervention studies are addressed, as well as the need for multiple omics approaches in microbiome research. Finally, we present an interdisciplinary perspective of the complexity of soy-microbiome interactions, potential for health promotion, and relationship to sustainability.

The human gut microbiome is a modifier of the risk for many non-communicable diseases throughout the lifespan. In ageing, the effect of the microbiome appears to be more pronounced because of the lower physiological reserve. Microbial metabolites and other bioactive products act upon some of the key physiological processes involved in the Hallmarks of Ageing. Dietary interventions that delay age-related change in the microbiome have also led to delayed onset of ageing-related health loss, and improved levels of cognitive function, inflammatory status and frailty. Cross-sectional analysis of thousands of gut microbiome datasets from around the world has identified key taxa that are depleted during accelerated health loss, and other taxa that become more abundant, but these signatures differ in some geographical regions. The key challenges for research in this area are to experimentally prove that particular species or strains directly contribute to health-related ageing outcomes, and to develop practical ways of retaining or re-administering them on a Population basis. The promotion of a health-associated gut microbiome in ageing mirrors the challenge of maintaining planetary microbial ecosystems in the face of anthropogenic effects and climate change. Lessons learned from acting at the individual level can inform microbiome-targeting strategies for achieving Sustainable Development Goals at a global level.