Our gut microorganisms, collectively known as the gut microbiota, affect far more than digestion. Bacteria in our intestinal tracts influence brain activity -- and even the likelihood of developing mental disorders. Decades of research have shown that a bacterially imbalanced gut can disrupt many systems in the human body, contributing to obesity, malnutrition and even cancer. In a study published May 10 in Nature, Stanford Medicine researchers and collaborators used an ingestible device to capture the diversity of microorganisms, viruses, proteins and bile in the small intestine.