A new study led by Danforth Center principal investigator Nigel Taylor and research scientist Narayanan Narayanan, demonstrated that it is possible to raise the iron and zinc content of cassava roots while maintaining yield and other plant characteristics that are important to farmers and consumers.
With the help of Ihuoma Okwuonu of the National Root Crops Research Institute, in Umudike, Nigeria, the team also confirmed that the higher mineral levels don’t disappear during cooking common West African foods, which means that better nutrition can actually reach the dinner plate and the digestive tract. In West Africa, micronutrient deficiency of minerals like iron and zinc has caused “hidden hunger” and other health problems, including anemia. Developing new varieties of a staple food crop like cassava with elevated levels of these two minerals could significantly improve diets and health.
Taylor, Narayanan, Okwuonu and other researchers in the VIRCA Plus project are now integrating the high iron and zinc trait into cassava varieties that are popular in Nigeria, with more field evaluations and assessments planned for 2019. Further development, testing and regulatory review are needed before iron and zinc biofortified cassava could be made available to farmers and consumers in the coming years.
Read the Danforth Center’s press release and the paper published today in Nature Biotechnology.
Ultimately it was a combination of two genes, IRT1 and FER1, from the model plant species Arabidopisis that led to cassava plants with iron concentration levels 6-12 times higher than conventional cassava and zinc concentrations that were 3-10 times higher. “It was a real challenge to find a combination of genes that would raise both iron and zinc levels and maintain them under field conditions without impacting yields,” stated the paper’s lead author, Dr. Narayanan Narayanan. To identify the impact of food processing on mineral levels in the biofortified cassava, researchers prepared gari and fufu, two common West African foods, by chopping, soaking, fermenting, pressing and roasting cassava. They found that high levels of iron and zinc were retained through these cooking processes and remained available for absorption in the gut following digestion. Ultimately the biofortified cassava could provide 40-50 percent of Estimated Average Requirements (EAR) for iron and 60-70 percent of EAR for zinc for children and women in West Africa. “Biofortified cassava has the potential to improve the nutrition and health of millions of people in West Africa,” said Taylor. “The higher iron and zinc would be present in every root harvested from these special plants, and therefore in every bite of food prepared from them.”