Nutrition

Biography

Biography: Ann-Sofie Sandberg

Abstract

Two billion people in the world suffer from iron deficiency. The magnitude of zinc deficiency is likely of the same order. Low absorption from plant-based diets is considered a major factor in the etiology of iron and zinc deficiency. Thus there is a need for sustainable methods for providing more bioavailable iron and zinc. The bioavailability of iron and zinc in plant foods is low due to the presence of inhibitors of iron and zinc absorption, despite a sometimes high content of theses metals. Inhibitors (phytate, and for iron also polyphenols) and enhancers (amino acids, for iron also ascorbic acid) in a meal affect the complexation and solubility of iron and zinc at the site of absorption in the gut and thus the availability. The speciation of iron is also crucial for uptake. Furthermore recent advances in knowledge concerning regulation of iron absorption show that dietary factors (ascorbic acid, calcium, polyphenols) have intracellular effects by influencing the iron uptake and transport proteins in the intestinal epithelial cells. Optimized biological processing techniques (malting, fermentation, addition of enzymes) are a means to substantially improve iron and zinc absorption from plant foods by enzymatic degradation of inhibitors or formation of enhancers. These methods can be used in combination with breeding and genetic engineering for biofortification with zinc, iron (ferritin), reduction of inhibitors and engineered yeast and lactobacillus strains for use in fermentation. Plant based foods then can become good sources of dietary iron and zinc. Efficacy trials in humans are still needed to prove the consequences for prevalence of iron and zinc deficiency on a population level.