Meet the ‘psychobiome’: the gut bacteria that may alter how you think, feel, and act

OVER THE PAST 20 YEARS, the recognition that the microbes living inside us outnumber our body’s own cells has turned our view of ourselves inside out. The gut microbiome, as it’s known, weighs about 2 kilograms—more than the 1.4-kilogram human brain—and may have just as much influence over our bodies. Thousands of species of microbes (not only bacteria but also viruses, fungi, and archaea) reside in the gut. And with as many as 20 million genes among them, those microbes pack a genomic punch that our measly 20,000 genes can’t match. Gut bacteria can make and use nutrients and other molecules in ways the human body can’t—a tantalizing source of new therapies. | READ THE FULL STORY