Micronutrients and the Link to Human Nutrition.

Food production has increased and needs to increase more, but undernutrition of micronutrients (e.g. iron, zinc, selenium) and other essential components of diets is also occurring. We know that nutrient yields of staple crops have decreased and some of the reasons for this are emerging. It seems that advances intended to increase yields have ignored the micronutrients, and that basically a dilution of those essential elements with carbohydrate is occurring in staple crops.

Working with the African Soil Information Service, we are using new methods to rapidly assess croplands in Africa and to quantify the geospatial, geochemical and geographical constraints on crop production and nutritional value. We are also developing new diagnostic techniques based on dry spectral techniques (XRF, MIR, XRD and laser PSA) and their standardization to collect analytical data very rapidly in Ghana, Nigeria, Ethiopia and Tanzania. In this way, soil and crop information can be analyzed and new diagnostic tools created that can be used to tailor fertilizer compositions to specific soil conditions.

Biofortification efforts for crop and human nutrition can benefit from this approach, as we can use it to determine the limiting factors for nutrient supply. Examples will be given of the specific conditions in which Zn deficiency occurs, and where crops contain concentrations of Se that are insufficient for human and animal nutrition. Genetic techniques for reversing the lack of micronutrients hold great promise. But we see that some of these biofortification techniques may not supply sufficient nutrients for human diets, at least not in the short term. Rapid techniques that we have developed to survey and map bioavailability of micronutrients are useful to determine where such approaches will work and where they will not, and point to situations in which other interventions will be needed, such as supplementation.