History of development of the concept and definition for “Probiotics” and “Prebiotics” and their perspective for future consensus

The terms “Probiotics” and “Prebiotics” which represent beneficial microbes and beneficial food substances for human health, respectively, have been used for several decades since they were firstly developed. The original ideas showing the importance of the gut microbiota for health were already argued more than a hundred years ago, and since then many efforts to demonstrate and practice the actual beneficial effects of certain microbes and substances have been implemented by a huge number of investigators. In this review article, I would like to summarize the history of argument of the concepts and definitions for “Probiotics” and “Prebiotics”, and see how we can find appropriate ways to reach future consensus.