Soil micronutrients linked to human health in India

Trace soil minerals are a critical determinant of both crop productivity and the mineral concentration of crops, therefore potentially impacting the nutritional status of human populations relying on those crops. We link health data from nearly 0.3 million children and one million adult women across India with over 27 million soil tests drawn from a nationwide soil health program. We find that soil zinc availability is positively associated with children’s linear height growth, and soil iron availability is positively associated with hemoglobin levels. The link between soil zinc and childhood stunting is particularly robust—a one standard deviation increase in satisfactory soil zinc tests is associated with approximately 11 fewer children stunted per 1000. We also find that this zinc-stunting relationship is strongest in wealthier households. Our results suggest that soil mineral availability impacts human nutritional status and health in at least some areas of India, and that agronomic fortification may be a beneficial intervention.