is useful to think of your microbial community as your own garden that you are responsible for. We need to make sure the soil (your intestines) that the plants (your microbes) grow in is healthy, containing plenty of nutrients; and to stop weeds or poisonous plants (toxic or disease microbes) taking over we need to cultivate the widest variety of different plants and seeds possible. I will give you a clue how we do this. Diversity is the key.
