Ann Prentice is Director of the MRC’s Human Nutrition Research Laboratory in Cambridge. She has championed the application of rigorous methodology to human nutrition in order to develop an evidence base for policy and practice. Her research in the UK, Gambia and China established that approaches to assessing calcium and phosphate metabolism and vitamin D supplementation that prevent rickets and osteoporosis in the developed world cannot be transferred simply to less developed countries. This is because of profound differences in genetic background and environmental exposures. Dr Prentice is also Chair of the Department of Health’s Science Advisory Committee on Nutrition.