There are good bacteria and bad bacteria. For millennia, we humans never made a distinction: bacteria were associated with diseases and death, no exception. It was known that we are carrying along a large assortment of microbes in our gut, but this was considered to be an evolutionary accident or a coincidence rather than a lucky occurrence for us. Recently, in the last 10-15 years, the scientists’ view on the bacteria living in our gut has changed drastically. Now we know that they are good for us in ways that we are just beginning to understand. What is already clear is that, without the bugs in our gut, we would be way worse off than we are.
Let us start with some numbers to put things in proportion: bacteria make up 1 to 3% of our body mass, which does not seem much. However, in absolute number, it means that we have approximately 10X more bacteria than we have cells in our body, which by itself is quite remarkable. The bacteria we carry around are also so diverse, belonging to literally hundreds of different species, that it is very hard to figure out the exact composition of one person’s bacterial population in detail. Not only they are more than “us