Biofortification of Food Legumes and Bioavailability of Nutrients

Abstract

Growing sufficient food will not in itself assure adequate nutrition and healthy productive lives. The diets of over two-thirds of the world’s population lack one or more essential mineral elements; as a result, micronutrient malnutrition, the so-called hidden hunger, affects more than one-half of the world’s population, especially women and preschool children. In developing countries, the rise in micronutrient deficiencies is linked to the shift in cultivation with dominance by cereals. High cereal productivity, the result of extensive research, has ensured that cereal production is relatively profitable with a relatively low risk of failure due to biotic and abiotic stresses. Food systems dominated by cereals are low in micronutrients. To address micronutrient deficiencies in the comprehensive way, several new approaches are needed simultaneously. Despite past progress in controlling micronutrient decencies through supplementation and food fortification, new approaches are needed to expand the reach of food-based interventions. Biofortification, a new approach that relies on conventional plant breeding and modern biotechnology to increase the micronutrient density of staple crops, holds great promise for improving the nutritional status and health of poor populations in both rural and urban areas of the developing world. Available genetic variation influences the level of micronutrient increments that can be achieved through breeding, but contribution to nutritional status largely depends on factors related to bioavailability that have to be considered when setting nutritional target levels for breeding. Critical information is needed on how much nutrient is retained after storage, processing, and cooking; on micronutrient bioconversion and bioavailability once the nutrient is ingested; and on micronutrient requirements of the target population. Many of these parameters are interrelated in a highly complex manner, since human micronutrient status, dietary composition, and health status affect bioavailability and its components’ bioaccessibility, bioconversion, and bioefficacy. The bioavailability of Fe and Zn is associated with the presence of antinutrients and/or the lack of promoter substances for micronutrients. Since an increase in bioavailability translates into a proportional decrease in the nutritional target increment (increasing Fe bioavailability from 5 % to 10 % reduces the target increment by 50 %), breeding strategies for micronutrient density should consider indirect breeding for increased bioavailability, increased retention, or reduced postharvest micronutrient deterioration. Although not well understood, breeding for increased bioavailability offers tremendous potential.