The first non-infectious disease that comes to mind is obesity. Although I don’t know a ton about possible relationships between obesity and microorganisms, I know that our gut is full of microorganisms that help us digest our food. Perhaps lacking certain microorganisms could result in obesity. Under the same train of thought, I think that Irritable Bowel Syndrome (IBS) is another non-infectious disease that may be the result of missing certain microorganisms in the body to help break down waste. Autoimmune disorders are the result of the body attacking itself so I believe that microorganisms could play a role in some of these diseases as well, although I do not know specifics.
