Anahad O’Connor in The Washington Post:
Every time you eat, you are feeding trillions of bacteria, viruses and fungi that live inside your gut. But are you feeding them the right foods? Scientists used to know very little about these communities of microbes that collectively make up the gut microbiota, also known as your gut microbiome. But a growing body of research suggests that these vast communities of microbes are the gateway to your health and well-being — and that one of the simplest and most powerful ways to shape and nurture them is through your diet. Studies show that our gut microbes transform the foods we eat into thousands of enzymes, hormones, vitamins and other metabolites that influence everything from your mental health and immune system to your likelihood of gaining weight and developing chronic diseases.
Gut bacteria can even affect your mental state by producing mood-altering neurotransmitters like dopamine, which regulates pleasure, learning and motivation, and serotonin, which plays a role in happiness, appetite and sexual desire. Some recent studies suggest that the composition of your gut microbiome can even play a role in how well you sleep.