A study published in Nature (486(7402): 222–227. doi:10.1038/nature11053) examines the human gut microbiome across age and geography. The research analyzed 531 individuals from three populations: healthy Amerindians from Venezuela's Amazonas, rural Malawian communities, and residents of U.S. metropolitan areas. Fecal samples were collected, and the microbiome's gene content was characterized. The study found that the gut microbiome undergoes functional maturation during the first three years of life, with age-related changes in genes involved in vitamin biosynthesis and metabolism. Pronounced differences in bacterial species and functional gene repertoires were observed between individuals in the U.S. and the other two countries. These differences were evident in early infancy and adulthood. The similarity of fecal microbiomes among family members extended across cultures, highlighting the importance of considering the microbiome when evaluating human development, nutrition, and physiological variations. The study also found that the microbiome's functional changes correlate with age and geography, with U.S. microbiomes clustering separately from non-U.S. ones. Bacterial diversity increased with age in all populations, with U.S. adults having the least diverse microbiomes. The study also examined the functional changes in the microbiome as children matured. It found that the representation of functional gene groups, such as those involved in vitamin biosynthesis and metabolism, varied with age and population. The microbiome's functional changes were influenced by diet and lifestyle, with differences in the representation of certain genes reflecting variations in dietary habits. For example, U.S. infants had higher representation of certain genes related to the metabolism of sugars, while Malawian and Amerindian infants had higher representation of genes related to the metabolism of glycans found in breast milk. The study also found that the microbiome's composition varied significantly between populations, with differences in the representation of certain bacterial taxa and functional genes. These differences were influenced by factors such as diet, cultural traditions, and geographic location. The study also found that kinship influenced the microbiome's composition, with family members showing similar microbial profiles despite differences in geography and culture. Overall, the study highlights the importance of considering the microbiome when evaluating human health and development. It underscores the need for broader cross-cultural and cross-age sampling to fully understand the variability in the human gut microbiome. The findings suggest that the microbiome is shaped by a combination of genetic, environmental, and lifestyle factors, and that understanding these factors is essential for developing effective strategies for health and nutrition.A study published in Nature (486(7402): 222–227. doi:10.1038/nature11053) examines the human gut microbiome across age and geography. The research analyzed 531 individuals from three populations: healthy Amerindians from Venezuela's Amazonas, rural Malawian communities, and residents of U.S. metropolitan areas. Fecal samples were collected, and the microbiome's gene content was characterized. The study found that the gut microbiome undergoes functional maturation during the first three years of life, with age-related changes in genes involved in vitamin biosynthesis and metabolism. Pronounced differences in bacterial species and functional gene repertoires were observed between individuals in the U.S. and the other two countries. These differences were evident in early infancy and adulthood. The similarity of fecal microbiomes among family members extended across cultures, highlighting the importance of considering the microbiome when evaluating human development, nutrition, and physiological variations. The study also found that the microbiome's functional changes correlate with age and geography, with U.S. microbiomes clustering separately from non-U.S. ones. Bacterial diversity increased with age in all populations, with U.S. adults having the least diverse microbiomes. The study also examined the functional changes in the microbiome as children matured. It found that the representation of functional gene groups, such as those involved in vitamin biosynthesis and metabolism, varied with age and population. The microbiome's functional changes were influenced by diet and lifestyle, with differences in the representation of certain genes reflecting variations in dietary habits. For example, U.S. infants had higher representation of certain genes related to the metabolism of sugars, while Malawian and Amerindian infants had higher representation of genes related to the metabolism of glycans found in breast milk. The study also found that the microbiome's composition varied significantly between populations, with differences in the representation of certain bacterial taxa and functional genes. These differences were influenced by factors such as diet, cultural traditions, and geographic location. The study also found that kinship influenced the microbiome's composition, with family members showing similar microbial profiles despite differences in geography and culture. Overall, the study highlights the importance of considering the microbiome when evaluating human health and development. It underscores the need for broader cross-cultural and cross-age sampling to fully understand the variability in the human gut microbiome. The findings suggest that the microbiome is shaped by a combination of genetic, environmental, and lifestyle factors, and that understanding these factors is essential for developing effective strategies for health and nutrition.