For the past decade, plant breeders have been trying to boost the vitamin and mineral content of rice and other staples through traditional plant breeding and genetic engineering. But the foods have never been tested to see if they actually improve the health of the people who eat them.
Now, in the first study to test people who eat foods that have been bred for higher-than-normal concentrations of micronutrients, researchers have confirmed that conventional plant breeding can affect human nutritional status. In a nine-month, double-blind study -- the gold standard of research methods -- the iron status of women who ate biofortified, iron-rich rice was 20 percent higher than in women who ate traditional rice.
"Although this sounds like a modest increase, it means that instead of 50 percent of women getting adequate iron, 71 percent of the women who consumed the biofortified rice, while eating a traditional Philippine diet, met the estimated average requirement for iron," said Jere Haas, the Nancy Schlegel Meinig Professor of Maternal and Child Nutrition at Cornell University and the lead author of the study, published in the December issue of the Journal of Nutrition (Vol. 135:12). "The greatest improvements in iron status were in non-anemic women who had the lowest body iron reserves at the beginning of the study and in women who consumed the most rice and, therefore, the most iron from rice," he said.
"The beauty of these findings is that using rice that is bred to be higher in iron has great potential as a sustainable approach to reducing the micronutrient deficiency problems so common in developing countries."
Haas and his colleagues tested the biofortified rice in the Philippines, where they monitored the diets of 192 Catholic religious sisters in 10 convents.
Lack of iron is the most common micronutrient deficiency in the world, afflicting more than 3.5 billion people, particularly in developing countries, according to the United Nations. During childhood and adolescence, iron deficiency impairs physical growth, mental development and learning capacity. In adults, it reduces the capacity to do physical labor. Severe anemia increases the risk of women dying in childbirth.
"It is estimated that about 56 percent of women in developing countries are anemic due mostly to iron deficiency," said Haas. "In the Philippines, where this study was conducted, as many as 60 percent of the women may be iron deficient." The experimental rice used in the study has four to five times more iron content than commercially available rice in the Philippines.
Many women in developing countries cannot afford or do not have access to commercially fortified foods, compared with women in industrialized countries who commonly consume foods fortified with vitamins and minerals.
Current methods to improve iron in diets in developing countries, such as providing dietary supplements and fortifying the food supply, have limitations, he said, or are not sustainable in countries where resources are scarce.
"This study shows that developing new varieties of staple foods, such as rice, maize, wheat, beans and cassava, by selectively breeding to enhance nutritional qualities has merit for reducing micronutrient deficiencies in the developing world," said Haas.
The biofortified rice was developed by the International Rice Research Institute (IRRI) in the Philippines. One of its major sponsors is HarvestPlus, an international, interdisciplinary research program that collaborates with Cornell and other universities and agencies to reduce micronutrient malnutrition by breeding nutrient-dense staple foods. One of the first crops to be biofortified under this initiative is rice, which is a staple food of some 3 billion people, many of them among the world's poorest.
Now that researchers know that the biofortified rice can actually improve the nutritional status of people who eat it under controlled experimental conditions, follow-up studies will not only seek to confirm these findings but also will look at how well the rice is accepted by the general population, Haas said.
Although researchers at Cornell were not involved in the development of the biofortified rice, they are actively involved in developing disease-, drought- and pest-resistant as well as higher yield rice varieties through genetic engineering.
Co-authors of the study include John L. Beard and Laura Murray-Kolb of Pennsylvania State University; Angelina Felix and the late Angelita del Mundo, University of the Philippines/Los Banos; and Glenn Gregorio, IRRI. The study was supported by the Canadian Micronutrient Initiative, Asian Development Bank, the Danish (DANIDA) Trust Fund and the International Food Policy Research Institute. It was presented last year at the Experimental Biology conference in San Diego, the American Society of Agronomy conference in Seattle and the World Rice Research Conference in Japan.