Scientists from the Stanford School of Medicine have discovered that both ethnicity and geographic location can significantly influence human biology, including metabolism, immunity, gut bacteria, and the aging process.

The research, published in the journal Cell, analyzed molecular data from 322 healthy participants of European, East Asian, and South Asian ancestry who were living across Asia, Europe, and North America. By comparing people with similar ethnic backgrounds living in different regions, researchers were able to separate genetic influences from environmental effects.

The team examined a wide range of biological markers, including proteins, lipids, microbes, and metabolites, to create a detailed molecular map of human diversity. According to study co-author Michael Snyder, the project offered one of the most comprehensive global molecular profiles ever conducted.

Researchers identified several ethnicity-related biological patterns. South Asian participants showed signs of greater pathogen exposure, while people of European ancestry demonstrated more diverse gut microbiomes and higher levels of metabolites linked to cardiovascular disease. These trends appeared regardless of where participants lived, suggesting a strong genetic contribution.

At the same time, geography also had a measurable impact on biology. People living outside their ancestral regions displayed changes in cholesterol metabolism, bile acid pathways, and gut microbiota composition.

One of the study’s most notable findings involved biological aging. East Asians living outside Asia appeared biologically older than those residing in Asia, while Europeans living outside Europe showed signs of younger biological age. Researchers say these differences may reflect the effects of diet, lifestyle, and environmental conditions on aging.

The scientists also uncovered a potential molecular connection between gut bacteria and cellular aging. They identified a relationship involving the telomerase gene, the gut microbe Oscillospiraceae UCG-002, and a lipid molecule called sphingomyelin, opening new directions for aging research.

According to the authors, the findings could help advance precision medicine by improving understanding of how genetics and environment jointly influence health and disease risk in diverse populations.