It’s hard to miss the headlines these days about the newest darling of the research world: gut bacteria. These microscopic cells reside in the human intestine in a big way, in the trillions by recent estimates. A growing body of research shows that keeping this bacterial community in proper balance has serious health benefits from a strong immune system to a positive mood to a healthy body weight and beyond. This balancing act fascinates me for two reasons. Not only does it have a profound potential for human health, but it adapts, often rapidly, to simple dietary changes. So we can add one more advantage to making smart choices about the foods and supplements we consume. We can dramatically change our gut bacteria– and health – for the better.