Iron bio-fortification and heavy metal/(loid)s contamination in cereals: successes, issues, and challenges

Abstract

Biofortification of micronutrients, particularly of the iron (Fe) in cereals, is a viable, attractive, and sustainable strategy to cope with malnutrition as cereals are the major staple diets, particularly in developing countries. Increased concentrations of heavy metal/(loid)s (HMs); i.e. cadmium (Cd), lead (Pb), arsenic (As) etc. in agricultural soils is an increasing and serious challenge, posing severe health problems through food chain contamination. Accumulation of HMs in plants is challenging and contrasts to the development of biofortification strategies to combat micronutrient deficiencies. Agricultural biofortification strategies aim to increase plant uptake of mineral nutrients from soil and the translocation/storage of micronutrients to edible portions of cereal grains. However, it also means that any strategy to increase the uptake of Fe in plants may result in increased uptake of other toxic HMs. Therefore, the issue of HM contamination in cereals needs further understanding. This review describes the advancements in Fe biofortification strategies and the conflicting issue of HM accumulation in the grain of cereals.