New rices may improve human health
Jo Anne Pamplona
December 1999, BAR Digest
Iron- and Zinc- Enriched Rice Undergoing Trial in Convent;Vitamin A-Enhanced and Iron-Enriched Rice Varieties to Be Tested
Nuns at a convent in the Philippines are eating iron-enriched, experimental rice as part of their daily diet in the hopes of improving the health of some 3.7 billion iron-deficient people around the world. The postulants and novitiates at the convent, who eat the same amount of food every day, are providing scientists with a unique opportunity to test whether the minerals that have been bred into new rice varieties will be absorbed by the human body.
“Rice is a staple food in many poor countries, particularly in Asia,” said Ronald Cantrell, director general of the Manila-based International Rice Research Institute (IRRI). “While rice fills the stomach, it is missing critical nutrients for human health such as iron and zinc.” An estimated 2 billion people worldwide–nearly one-third of the world’s population–suffer ill health due to iron-deficiency anemia, the most widespread nutrient deficiency in the world. Between 40 and 50 percent of children under the age of five in developing countries are iron deficient. The disorder hits pregnant women especially hard, accounting for up to 20 percent of all maternal deaths. It also impairs immunity and reduces the physical and mental capacities of people of all ages. The prevalence of zinc deficiency is unknown, but it is a likely problem wherever malnutrition occurs. “Fortification programs have proven too expensive and relatively ineffective in reaching the billions of malnourished people who need them,” said Cantrell. “For a country such as India, it would cost $93 million each year for an iron supplement program.”
A concerted effort at IRRI has yielded an approach that is far cheaper — packing rice with minerals through traditional plant breeding. After extensive analysis and breeding over a four-year period, scientists have developed a rice variety that has an extremely high iron and zinc content, as well as good yield flavor, texture, and cooking qualities, explained Cantrell.
Now scientists are poised to discover whether the nutrients are still present in the rice following the milling process and whether they are “bioavailable” for humans after they are digested. Experiments in rats and in human colon cell cultures at Cornell University have verified that the extra iron is available. But these initial results need to be duplicated in human trials.
With the Institute of Human Nutrition of the University of the Philippines Los Baños, IRRI is conducting a feeding trial in the convent in the Philippines. The postulants and novitiates are all young women of about the same age. The trial has been in progress since April and will continue for several more months. A large-scale feeding trial is planned to confirm the results from this initial trial.
In a related advance, Swiss researchers recently announced a breakthrough in genetically modifying rice grains to contain more iron and vitamin A. Vitamin A deficiency causes more than 1 million childhood deaths each year and is the single most important cause of blindness among children in developing countries. Researchers from The Swiss Federal Institute of Technology’s Institute for Plant Sciences inserted genes from a daffodil and a bacterium into rice plants. The resulting rice plant produces a grain with sufficient beta-carotene — converted to vitamin A in humans — to meet total vitamin A requirements in a typical Asian diet. To double the iron content in rice, the research team added a gene from a French bean.
The Swiss research was conducted with funding from governments and not-for-profit organizations, including The Rockefeller Foundation, and will be freely available to national and international agricultural research centers. Researchers at IRRI will also carry out further research. They will adapt and develop rice varieties and test them to determine their effect on human health and the environment.
“After acceptance by national biosafety authorities, these novel varieties of rice will be distributed free of charge to farmers who will have unrestricted rights to them,” said Gurdev Khush, principal plant breeder at IRRI.