Our gut bacteria may act as a foe of our brain

Fatty acids, the simplest form of lipids, are basic building blocks of our life. With their various structure diversity (such as the length of carbon chain, numbers of double bonds, cis-trans forms and other functional residues on the main carbon chain, for example hydroxyl or methyl groups), they are expected to perform various unique and critical functions in biological process. Otherwise those structural diversity would be gradually lost during the billions years of natural selection (1). Unfortunately, our knowledges about fatty acid functions are still very limited. It is important to know that except our own cells and food uptake, the gastrointestinal bacteria residing in our body can also produce a lot of fatty acids during fermentation processes, in particular, acetate, propionate, and butyrate (2). The effects of those SCFAs were not attracting much attending until recent several exciting discoveries (3).