DuPont Pioneer advancements in biofortification increase availability, longevity of beta-carotene in sorghum grain

DuPont Pioneer and Africa Harvest Biotech Foundation International researchers have demonstrated that increasing vitamin E and beta-carotene production in sorghum markedly improves the availability and longevity of beta-carotene, which the body converts to vitamin A. This could be especially meaningful for Sub-Saharan Africa, where the prevalence of vitamin A deficiency has remained high and unchanged since the early 1990’s.

For children up to age three who rely on sorghum as a staple, we should be able to provide 100 percent of vitamin A Estimated Average Requirement (EAR) for up to a month after harvest, via beta-carotene. We also should be able to provide more than 20 percent EAR needs for extended periods of time after sorghum grain harvest,” said Ping Che, DuPont Pioneer research scientist. “And we’re not finished – we believe even higher levels of vitamin A throughout the year are possible.”

Without biofortification, sorghum grain -- a mainstay in many diets -- is seriously deficient in vitamin A, iron and zinc. Vitamin A deficiency causes a number of symptoms, including blindness and an increase in mortality from measles and diarrhea. Long-term deficiencies can cause permanent mental and physical impairment.

The DuPont Pioneer research team identified oxidation as the main factor in rapid breakdown of beta-carotene in sorghum grain. They were able to slow degradation by inserting a gene from barley, which serves to increase vitamin E. A powerful anti-oxidant, vitamin E also helps more than double the half-life of beta-carotene in grain stored under normal conditions. In this case, it improved an unprotected half-life of 2-3 weeks to 8-10 weeks. The finding was recently reported in the journal Proceedings of the National Academy of Sciences.

Biofortified crops have improved the human condition wherever implemented and are also an economical and sustainable means of providing higher levels of micronutrients in diets of at-risk populations. Biofortified crops already making a difference in Africa and Asia include beans, sweet potato, millet, and maize, with increases in iron, zinc, and vitamin A as the target micronutrients. While dietary diversity remains the long term goal, biofortified crops can play an important role until improved diets are more common.

“We’re pleased that we’ve made continual progress and have been able to develop a more nutritious sorghum grain,” said Marc Albertsen, DuPont Pioneer research director. “We look forward to the day when the most at-risk members of African society can benefit from this research. We appreciate the collaborators who help us move the effort forward.”

The Bill and Melinda Gates Foundation provided the initial funding for the biofortified sorghum project, with help from the Howard G. Buffett Foundation. More recent efforts have relied upon funding and in-kind donations from the Pioneer Foundation and DuPont Pioneer. African leadership for the effort has come from African Harvest, a non-governmental organization based in Nairobi, Kenya, who worked closely with the Nigerian Institute of Agricultural Research and the Kenya Agriculture and Livestock Research Institute.