The importance of dietary protein in human health: combating protein deficiency in sub-Saharan Africa through transgenic biofortified sorghum.

Child malnutrition is increasing in Africa. Protein deficiency is an important cause since protein is essential for both growth and maintenance of muscle mass. Sorghum is a major staple food in Africa on account of its hardiness as a crop. However, sorghum protein is very deficient in the indispensable amino acid lysine and on cooking has poor protein digestibility. This results in sorghum having a very low Protein Digestibility Corrected Amino Acid Score (PDCAAS). The Africa Biofortified Sorghum project, a Grand Challenges in Global Heath project, is undertaking research to biofortify sorghum in terms of protein and micronutrient quality using genetic engineering. Lysine and protein digestibility have been improved by suppression of synthesis of the kafirin storage proteins. Transgenic biofortified sorghum has double the PDCAAS of conventional sorghum. This improvement should enable a young child to meet most of its protein and energy requirements from biofortified sorghum porridge. This together with the improvement in micronutrients could provide the basis of a sustainable and broadly comprehensive solution to child malnutrition in many African countries.