You are only 43% human! Who lives inside?

The human body inhabits countless microorganisms that can not only “be friends” with us, but also lead to health problems. In this issue we will describe both of them.

According to the latest research, more than half of the cells in our bodies are non-human. The remaining 57 % of the human body are bacteria, viruses, fungi and archaea that populate not only the outer skin layer, but also all the internal organs. At the same time, if we consider that the human genome consists of only 20 thousand genes, and the microflora of the human body exceeds that figure by a factor of a hundred, it becomes clear that we are “an upright-walking home” for the other Earth creatures. Scientists call this “our second genome”, which greatly affects human life. It is, for example, responsible for the development of allergies, obesity and Parkinson’s disease. Moreover, small creatures living in our body affect depression and autism, as well as regulate the uptake of cancer-fighting drugs.

Probably, each of you heard of some beneficial bacteria and probiotics that are supposedly “terribly” useful for our body and are contained in special medicines and yoghurts. As it turned out, there is more marketing than truth. In September 2018, an extensive study was published saying that the majority of beneficial bacteria almost immediately leave our body naturally, and those that remain have only a minor effect, since they are not appropriate for a particular person. It means that the selection of probiotics should be done individually, without selling a millions copies of them in pharmacies.

In conclusion, we would like to say about the bacteria and space. At NASA, there are so-called clean rooms, absolutely sterile places where spacecrafts are assembled in order to avoid transfer of harmful organisms to other planets. In 2007, scientists collected samples from these rooms that were influenced extreme temperatures, radiation, hydrogen peroxide and other powerful antibacterial agents. What a surprise it was to find about a hundred species of surviving bacteria, 45 of which were unknown at the time. Since then, NASA can only guess how many unknown pathogens have been sent from Earth to Mars or the Moon, which have been studied for years now.