Ithaca, New York
November 29, 2005
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.
By Susan S. Lang |