Have you heard of prebiotic foods? They are foods that promote the growth of good bacteria in the gut. They are mainly fiber or complex carbs that can not be digested by human cells, but certain species of bacteria in the gut break them down and use them for fuel. This is turn promotes a healthy gut biome. Oats are a prebiotic food. They contain large amounts of beta-glucan fiber. This type of fiber helps aid the gut by feeding healthy bacteria. Flax seeds are also an excellent prebiotic. They are jammed full of soluble and insoluble fiber which furthers the process of a healthy gut flora.