Districts with more soil zinc samples showed significantly lower stunting rates and underweight children.
According to a new study, there is a strong association between soil micronutrients and people’s nutritional outcomes, with nutrient-deficient soil contributing to nutritional deficits in children and adult women.
The research, titled “Soil Micronutrients and Their Impact on Human Health in India,” which was published in Nature magazine on August 21, 2023, revealed that districts with a higher proportion of soil samples lacking sufficient zinc exhibited notably lower rates of child stunting and underweight cases. Additionally, one study indicated a connection between soil zinc availability and an increase in women’s height. Furthermore, a separate set of studies established a strong correlation between soil iron availability and anemia in women, as well as hemoglobin levels in both children and women.
These discoveries carry notable significance for India due to two primary reasons. Initially, over 35% of the nation’s soil has been identified as lacking adequate zinc content, and an additional 11% is projected to suffer from insufficient iron levels.
Secondly, as per the Global Nutrition Report of 2018, India is home to nearly a second of the global population grappling with micronutrient deficiencies. Within India, iron deficiency stands as the foremost cause of anemia.
While child stunting was over 39% according to the Lancet’s Global Burden of Disease Study 1990-2017, hunger was one of the main risk factors for loss of Disability-Adjusted life years in 1017.
For the current soil micronutrient deficiency study, researchers from Stanford University, Ohio State University, and Deakin University in Australia discovered that “a one standard deviation increase in satisfactory soil zinc is associated with a 0.29 cm increase in women’s heights.”
Inadequate zinc levels in humans are known to impede proper height development, and the research results indicate that crops cultivated in such soil were deficient in the zinc needed for their growth. Similarly, an increase of one standard deviation in sufficient soil zinc is linked to a decrease in stunted growth in children by 10.8 cases per 1000 children and a decrease in underweight cases by 11.7 per 1000 children.
Despite the conversation in India concerning the relationship between soil zinc and human zinc status, this is the first large-scale study to look at the relationship between soil mineral availability and human nutritional status.
The authors used data from approximately 27 million soil tests conducted in recent years by the central government’s Soil Health Card scheme, which was publicly available at the district level, from 2017 to 2019. Data on children’s and women’s health, as well as data from research controls, were obtained from India’s National Family Health Survey (NFHS) in 2015-2016.