Dietary deficiencies of zinc and iron are a substantial global public health problem. An estimated two billion people suffer these deficiencies1, causing a loss of 63 million life-years annually2,3. Most of these people depend on C3 grains and legumes as their primary dietary source of zinc and iron. Here we report that C3 grains and legumes have lower concentrations of zinc and iron when grown under field conditions at the elevated atmospheric CO2 concentration predicted for the middle of this century. C3 crops other than legumes also have lower concentrations of protein, whereas C4 crops seem to be less affected. Differences between cultivars of a single crop suggest that breeding for decreased sensitivity to atmospheric CO2 concentration could partly address these new challenges to global health.

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We thank L. S. De la Puente, M. Erbs, A. Fangmeier, P. Högy, M. Lieffering, R. Manderscheid, H. Pleijel and S. Prior for sharing data from their groups with us; H. Nakamura, T. Tokida, C. Zhu and S. Yoshinaga for contributions to the rice FACE project; and M. Hambidge, W. Willett, D. Schrag, K. Brown, R. Wessells, N. Fernando, J. Peerson and B. Kimball for reviews of earlier drafts or conceptual contributions to this project. V.R. thanks A. L. Harvey for her efforts in producing the phytate data included here. The National Agriculture and Food Research Organization (Japan) provided the grain samples of some rice cultivars. We thank the following for financial support of this work: the Bill & Melinda Gates Foundation; the Winslow Foundation; the Commonwealth Department of Agriculture (Australia), the International Plant Nutrition Institute, (Australia), the Grains Research and Development Corporation (Australia), the Ministry of Agriculture, Forestry and Fisheries (Japan); the National Science Foundation (NSF IOS-08-18435); USDA NIFA 2008-35100-044459; research at SoyFACE was supported by the US Department of Agriculture Agricultural Research Service; Illinois Council for Food and Agricultural Research (CFAR); Department of Energy’s Office of Science (BER) Midwestern Regional Center of the National Institute for Climatic Change Research at Michigan Technological University, under Award Number DEFC02- 06ER64158; and the National Research Initiative of Agriculture and Food Research Initiative Competitive Grants Program Grant no. 2010–65114–20343 from the USDA National Institute of Food and Agriculture. Early stages of this work received support from Harvard Catalyst | The Harvard Clinical and Translational Science Center (National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health Award 8UL1TR000170-05).

Author information


  1. Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, 02215, USA

    • Samuel S. Myers
    • , Antonella Zanobetti
    •  & Joel Schwartz
  2. Harvard University Center for the Environment, Cambridge, Massachusetts 02138, USA

    • Samuel S. Myers
  3. The Department of Geography and Environmental Development, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva, Israel

    • Itai Kloog
  4. Department of Earth and Planetary Science, Harvard University, Cambridge, Massachusetts 02138, USA

    • Peter Huybers
  5. Department of Plant Biology and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA

    • Andrew D. B. Leakey
  6. Department of Plant Sciences, University of California at Davis, Davis, California 95616, USA

    • Arnold J. Bloom
    •  & Eli Carlisle
  7. University of Pennsylvania, Department of Biology, Philadelphia, Pennsylvania 19104, USA

    • Lee H. Dietterich
  8. Department of Environment and Primary Industries, Horsham, Victoria 3001, Australia

    • Glenn Fitzgerald
  9. National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki, 305-8604, Japan

    • Toshihiro Hasegawa
    • , Hidemitsu Sakai
    •  & Yasuhiro Usui
  10. Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA

    • N. Michele Holbrook
  11. United States Department of Agriculture Agricultural Research Service, Soybean/Maize Germplasm, Pathology, and Genetics Research Unit, Department of Crop Sciences, University of Illinois, Urbana, Illinois 61801, USA

    • Randall L. Nelson
  12. School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA

    • Michael J. Ottman
  13. United States Department of Agriculture Agricultural Research Service, Aberdeen, Idaho 83210, USA

    • Victor Raboy
  14. The Nature Conservancy, Santa Fe, New Mexico 87544, USA

    • Karla A. Sartor
  15. Department of Agriculture and Food Systems, Melbourne School of Land and Environment, The University of Melbourne, Creswick, Victoria 3363, Australia

    • Saman Seneweera
  16. Department of Forest and Ecosystem Science, Melbourne School of Land and Environment, The University of Melbourne, Creswick, Victoria 3363, Australia

    • Michael Tausz


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S.S.M. conceived the overall project and drafted the manuscript. A.Z., I.K., J.S. and P.H. performed statistical analyses. P.H. and A.D.B.L. provided substantial input into methods descriptions. A.J.B., E.C. and V.R. analysed grain samples for nutrient content. G.F., T.H., A.D.B.L., R.L.N., M.J.O., H.S., S.S., M.T. and Y.U. conducted FACE experiments and supplied grain for analysis. N.M.H. and P.H. assisted with elements of experimental design. K.A.S. and L.H.D. assisted with data collection and analysis. All authors contributed to manuscript preparation.

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The authors declare no competing financial interests.

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Correspondence to Samuel S. Myers.

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