Associate Professor at Bryan College of Health Sciences Participates in International Study Showing Rising Levels of Carbon Dioxide Diminish Nutritional Content in Rice
A new study shows, for the first time, pervasive declines in the levels of vitamins B1, B2, B5, and B9 in rice grown at carbon dioxide (CO2) concentrations anticipated in this century. The study linked reductions in the nutritional quality of rice to dietary impacts for approximately 600 million people living in the poorest rice-dependent countries.
The study, published in Science Advances, a peer-reviewed open access journal of the American Association for the Advancement of Science, also confirms earlier findings of lower mineral and protein concentrations in rice and most other plants exposed to elevated CO2 levels. “As CO2 concentrations keep rising, the quality of plants keeps declining globally,” said co-author Irakli Loladze, a mathematical biologist and an Associate Professor at Bryan College of Health Sciences. “The footprint of such a chronic nutritional impoverishment in crops on human health is increasing with every passing year.”
An international team of scientists, including researchers from Bryan College of Health Sciences in Lincoln, Nebraska, the United States Department of Agriculture, and institutions in Washington, Australia, China and Japan, estimated the dietary impact of lower rice quality on individual countries and found the impact to be greatest for countries with the lowest per capita gross domestic product (GDP).
Researchers raised common rice varieties in open fields in China and Japan under current and elevated CO2 conditions. They found that rice grains from the elevated CO2 plots had 17% less Vitamins B1 (thiamine) and B2 (riboflavin), 13% less Vitamin B5 (pantothenic acid); and 30% less Vitamin B9 (folate) – vitamins essential for humans. “Rice has been a dietary staple for thousands of years for many populations in Asia and is the fastest growing food staple in Africa,” said co-author Kristie Ebi, director of the Center for Health and the Global Environment (CHanGE) at the University of Washington. “Reductions in the nutritional quality of rice could affect maternal and child health for millions of people.”
Elevated concentrations of CO2 stimulate plant growth and boost the synthesis of sugars and starch, diluting the levels of other nutrients in plant tissues. “We recognize that CO2 is plant food; but as with humans, more food can result in unforeseen consequences,” said Lewis Ziska, research plant physiologist for the Adaptive Cropping Systems Lab of the USDA-Agricultural Research Service. “For plants those consequences, from medicines to poison ivy, from herbicide effectiveness to nutrition, are, for the most part, not well understood. Unfortunately, not understanding them will have consequences for humanity as a whole.”
Chunwu Zhu of the State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences is the senior author. Lewis Ziska is the corresponding author. The research team also included the University of Washington, Seattle; the University of Tokyo; Bryan College of Health Sciences; and the University of Southern Queensland.