Katherine Daiy

Human obesity and metabolic disease may be partly explained by an evolutionary mismatch between evolutionarily novel exposures and the sensitive development of the human gut microbiome. The human gut microbiome is a community of microorganisms integral to energy metabolism. The gut microbiome assembles in a ‘sensitive period’ within the first year of life. Exposure to ultra-processed Western diets and antibiotics during infancy may radically shift early microbial ecology in ways that alter gut microbiome composition and consequentially, microbial energy-extractive capacity. This may facilitate adipose tissue deposition during infancy, ultimately affecting long-term risk for obesity and metabolic disease. At the same time, exposures affecting microbial development and growth are likely embedded in local contexts. By integrating the concepts of sensitive periods, evolutionary mismatch, and situated biologies, this project will examine how infant complementary feeding and antibiotic exposure modulates the infant gut microbiome and growth in Samoa, a nation with rising obesity prevalence. I will test the hypothesis that both Western complementary feeding patterns and antibiotic exposure alter the infant gut microbiome of Samoan infants in ways that promote fat deposition and program later metabolic phenotype, while examining how local cultural contexts in Samoa shape these exposures.