Biofortification is an umbrella term for a diverse range of projects and possibilities. It is best understood on three levels: as a range of technologies for developing micronutrient – dense crops; a development intervention to improve public health; and an idea that links agriculture, nutrition and health in a particular way. This paper focuses on the Golden Rice project as a well – known example of biofortification. It show how two sets of questions – concerning effectiveness of Golden Rice as a delivery mechanism for vitamin A to malnourished populations; and its acceptance by those populations as a rice variety and staple food item – have been narrowed down to parameters set by an increasingly polarised GM crop debate. It is not too late for these trends to be reversed, however. The Golden Rice project is a case study in the non – linearity of complex innovation processes , which exposes limitations of binaries such as ‘upstream’ and ‘downstream’. Recent developments point to the possibility of a more open debate about outstanding uncertainties and how they might be resolved.