From birth on, we encounter and become home to hundreds of microbial species. In fact, the 100 trillion bacterial cells inside us outnumber our cells ten to one and bring eight million bacterial genes to cohabitate with our 22,000 genes. This enormous and diverse ecosystem — the human microbiome — functions as another organ.
Scientists are only just beginning to understand its influence on human development, physiology, immunity, and nutrition. Some microbes may affect diseases like obesity, Type 1 diabetes, Crohn’s, asthma, multiple sclerosis, and even our mental health. Venture into the mysterious realm of the gut and learn how the microbiome impacts human health.