Hidden shift of the ionome of plants exposed to elevated CO(2) depletes minerals at the base of human nutrition

Mineral malnutrition stemming from undiversified plant-based diets is a top global challenge. In C(3) plants (e.g., rice, wheat), elevated concentrations of atmospheric carbon dioxide (eCO(2)) reduce protein and nitrogen concentrations, and can increase the total non-structural carbohydrates (TNC; mainly starch, sugars). However, contradictory findings have obscured the effect of eCO(2) on the ionome—the mineral and trace-element composition—of plants. Consequently, CO(2)-induced shifts in plant quality have been ignored in the estimation of the impact of global change on humans. This study shows that eCO(2) reduces the overall mineral concentrations (−8%, 95% confidence interval: −9.1 to −6.9, p<0.00001) and increases TNC:minerals > carbon:minerals in C(3) plants. The meta-analysis of 7761 observations, including 2264 observations at state of the art FACE centers, covers 130 species/cultivars. The attained statistical power reveals that the shift is systemic and global. Its potential to exacerbate the prevalence of ‘hidden hunger’ and obesity is discussed. DOI: http://dx.doi.org/10.7554/eLife.02245.001