Gut Microbiota in Nutrition and Health

This article, on the role of the gut microbiota in nutrition and health, is another in the BMJ series of open access, peer-reviewed articles examining controversial nutrition topics where there are uncertainties in the evidence and debate among experts. 

Most of the human studies of the gut microbiota and its associations with disease conditions are case control observational studies, conducted at one point in time (1). It is not possible from these studies to know whether the patterns...