Background: India has made important strides in reducing nutritional deficiencies over the past several decades. However, for micronutrients such as zinc, previous studies have suggested a worsening situation, contrary to most other dietary indicators. Adding to this burden, higher carbon dioxide (CO2) levels of 550 ppm, projected to potentially occur within decades, could reduce the zinc content of many staple crops.
Objective: To assess the historical prevalence of inadequate zinc intake, as well as to estimate the future prevalence attributable to rising CO2.
Methods: Seven household food consumption surveys between 1983 and 2012 were used to calculate total dietary zinc, phytate, and absorbable zinc intakes and to assess the prevalence of historic inadequacy in zinc intake. The added nutritional effect of elevated CO2 on zinc intake is then modeled.
Results: Prevalence of inadequate absorbable zinc intake has increased from 17.1% (15.3%-19.0%) in 1983 to 24.6% (22.3%-27.1%) in 2011-12, corresponding to an additional 82 million people consuming inadequate zinc than would have otherwise if 1983 rates had persisted. These increases in inadequacy have been driven by a relatively constant zinc intake being increasingly insufficient to meet a 5% growth in zinc requirements due to the aging of the population. Reaching 550 ppm CO2 by 2050 could potentially increase the prevalence of inadequate zinc intake by another 3.9 percentage points (2.1-5.8), corresponding to 65 million additional people having inadequate zinc intake.
Conclusions: The persistently worsening trend for zinc-opposite most other measures of human nutrition-shows that it may pose an ongoing risk unless addressed.
Keywords: India; climate; household expenditure surveys; micronutrient deficiency; nutrient intake; zinc.