Expert: Walter Hintz - 10/11/2007

Question
A discover magazine web article states that 90 percent of the cells in the human body is not human in origin but are microbes. This percentage is surprising to me. Is there scientific consensus for this claim. What percentage of weight and volume of our body is from microbes?

Link http://discovermagazine.com/2007/jun/your-body-is-a-planet


Answer
I believe this is a generalization.  The author is considering other microbes as well as bacteria and it would constantly change. The microbes would be on the surface of the body and in the intestinal tract.  Take a shower and have a bowel movement and a lot of them are gone. Blow your nose and more are gone.
I am not aware of any scientific studies about this. I did not see any bibliography at the end of the article.
 It if were true then they would not take up a lot of the total body mass.