Health experts call bacteria “good” and “bad”. Bad bacteria make us sick. Good bacteria help us digest food, and a few other things. Let me propose another view. Any bacteria (i.e., bacterial species) will make us sick if it becomes too numerous — so all bacteria are “bad”. All bacteria protect us against other bacteria — so all bacteria are “good”. The terms “good” and “bad” are misleading. It is like saying a person is inherently rich or poor. Anyone, given a lot of money, becomes rich. Anyone whose money is taken away becomes poor. Low bacterial diversity or reduction of diversity makes it more likely that one bacterial species can overwhelm its competitors, producing sickness. When this happens, to say that the species (e.g., H. pylori) that became numerous “caused” the sickness (e.g., ulcers) is to seriously misunderstand what happened and how to prevent it from happening. We are taught that our immune system protects us from infection. We should be taught that bacterial diversity does the same thing. Continue reading “Bacteria are Neither Good nor Bad”