There is a  saying that we are what we eat. For a long time we have been talking about food in terms of energy value, vitamins, minerals, and other components that are directly assimilable by human. However, over the past few years it has become more and more clear that the bacteria living in our gut (microbiota) have a great impact on our health. In fact, there are as many bacterial cells in the intestine than we have our own cells. Bacteria are small, and therefore in the terms of mass they weigh less, but the large number of bacterial cells must be highlighted. The bacteria living in our intestine are not all the same, but they belong to hundreds of different species. It has also become clear that dysbiosis in bacterial communities are associated with different diseases. The major attention in this context is on allergies and food intoleranceobesity, as well as the side effects of antibiotic therapy. There is an increasing amount of evidence that intestinal bacteria influence other organsystems establishing links to brain activity, respiratory diseases, diabetis and others.




One of the most important sources for intestinal bacteria is our food that acts both as a source of bacteria (probiotics) and it also shapes the composition of bacterial communities through the nutrients available for the bacteria to consume (prebiotics). 

In case the two effects are combined we will get synbiotics, foods that influence the gut microbiome through two different mechanisms.

Various pre- and probiotics are produced in form of capsules and fermented foods. Are these the only options to influence our bacterial communities? Considering the high number of different bacterial groups in our gut, we would expect that the effective probiotics do not contain one bacterial strain but help to introduce a new set of bacteria into our gut. 

Many diseases that are linked to bacterial communities are becoming more common in western societies. Studies among people from different cultures have shown more diverse bacterial communities in people living in traditional argicultural societies. Interesting discussion on the topic can be found here

(part I, part II).