Dr Jay Berkley tells us about his work on childhood nutrition and immunity in East Africa. Malnutrition is responsible for almost a third of childhood mortality worldwide. A better understanding of the bacteria in a child's gut will assist researchers in developing better treatment options. Dr Jay Berkley works in the KEMRI/Wellcome Trust Collaborative Research Programme in Kilifi, Kenya. His research interests include tackling the infection and inflammation of the gut to prevent mortality in malnourished children. He is also an expert advisor on severe acute malnutrition to the Ministries of Health, and the World Health Organisation. Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales; http://creativecommons.org/licenses/by-nc-sa/2.0/uk/