Improving iron bioavailability with ferritin overexpression in low phytate maize

Abstract

Iron deficiency anemia (IDA) is a major global nutritional problem may be due to lack of diversity in the diet, with maize as a staple crop. Iron bioavailability from maize is low due to its high phytate content. Iron content can be increased by expressing ferritin but this in itself may not overcome the inhibitory effect of phytate on bioavailability. We hypothesized that iron from low phytate maize (lpa‐1‐1 with 50–60% lower phytate than wild type) is more bioavailable than from wild type maize (A188), and increasing the iron content of lpa‐1‐1 will further increase iron bioavailability. We generated transgenic maize lines with enhanced iron content by over expressing soybean ferritin, and used the Caco‐2 cell culture model to determine iron bioavailability from these transgenic lines. Total iron content in transgenic maize was 2.5‐fold and 1.8‐fold higher in A188 and lpa‐1‐1 maize, respectively. Iron bioavailability from non‐transgenic lpa1‐1 was 50% (p<0.01) higher than A188 maize. Ferritin over expression improved iron bioavailability by 60% in A188 maize. Overall, transgenic lpa1‐1 showed higher bioavailability (16–38%; p<0.02) when compared to A188 transgenic maize. Our results suggest that over expression of ferritin in low phytate maize significantly improves iron bioavailability from maize, and is a potential approach to alleviate IDA. Supported by NWRC, Iowa State University