Submitted to: Nature
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/24/2014
Publication Date: 5/7/2014
Citation: Myers, S.S., Zanobetti, A., Kloog, I., Bloom, A., Carlisle, E., Dietterich, L.H., Fitzgerald, G., Hasegawa, T., Holbrook, N.M., Huybers, P., Leakey, A.D., Nelson, R.L., Ottman, M.J., Raboy, V., Sakai, H., Sartor, K.A., Schwartz, J., Seneweera, S., Tausz, M., Usui, Y. 2014. Rising atmospheric CO2 lowers food zinc, iron, and protein concentrations. Nature. 510:139-142. Interpretive Summary: More research is needed to understand how global climatic change might impact the nutritional quality of basic food crops. One of the most important aspects of cereal and legume nutritional quality when used in human foods is their bioavailability of mineral nutrients like iron, zinc and protein. Factors which affect mineral bioavailability include the amount of minerals in grain- or legume-derived foods, but also include the levels of antinutrients like phytic acid. In this study of several food crops including wheat, rice, maize, soybeans and field pea, it was demonstrated that elevated CO2, a possible component of climate change, can result in reduced levels of zinc, iron and protein in “C3” crops such as wheat, rice, soybean and field pea, but not in a “C4” crop like maize. The biological basis for this is probably that “C4” crops utilize CO2 more efficiently, and in a different manner, than do C3 crops. Reductions in phytic acid were also observed, but were not observed consistently across different crops, and the differences observed would not greatly alter nutritional quality. Therefore, global climate change may have a negative impact on crop nutritional quality in terms of their zinc, iron and protein levels. Crop breeders will need to include breeding for maintenance or increase of these nutritionally important food constituents as global climate change occurs in the future.
Technical Abstract: Dietary deficiencies of zinc and iron are a major global public health problem. Most people who experience these deficiencies depend on agricultural crops for zinc and iron. In this context, the influence of rising concentrations of atmospheric CO2 on the availability of these nutrients from crops is important but unresolved. We report that C3 grasses and legumes, which comprise the bulk of global caloric intake, have lower concentrations of zinc and iron when grown at elevated atmospheric CO2 concentrations. C3 crops other than legumes also have lower concentrations of protein, whereas C4 crops are unaffected. Response differences between cultivars suggest breeding crops for reduced sensitivity to changes in atmospheric CO2 concentration. Such breeding efforts may partly address the new challenges to global health that these findings highlight.