Selenium deficiency risk may increase due to climate change: Study
Climate-change models revealed that changes in climate and soil organic carbon content could lead to decreased soil selenium (Se) concentrations.
According to the team, these decreases could increase the prevalence of Se deficiency in humans.
In addition, the climate–soil interactions suggested that other trace elements, including copper, zinc and selenium, could be similarly affected by climate change.
“Coupled with micronutrient stripping from agricultural lands, predicted losses of total Se in soils indicate that the nutritional quality of food may decrease, thereby increasing the worldwide risk of micronutrient deficiency,” the study predicted.
A data intensive method
Using a data-mining approach, the team from the Swiss Federal Institute of Aquatic Science and Technology were able to model global soil Se concentrations.
In total, 16 datasets were assessed that consisted of 33,241 soil data points taken from 1994 to 2016.
Closer inspection of the Se concentrations contained in the top 30 centimetres (cms) of soil, were recorded along with their change in quantity when combined with 26 environmental variables.
These variables included precipitation, which can lead to leaching of Se from the soil.
According to the team, higher Se concentrations were likely to be found in locations with low to moderate precipitation and high clay content.
Equally, lower Se concentrations were likely to occur in dry areas with high pH and low clay content.
Taking these insights, the team then demonstrated average soil Se concentrations for the years 1980 to 1999 and 2080 to 2099.
Results indicated that selenium levels were generally predicted to decrease by the end of the century (2080–2099).
Approximately 66% of croplands would lose selenium with agricultural areas of Europe and south-western United States particularly affected.
“These losses could have implications for human health – at present, up to 1 billion people are thought to be affected by low dietary selenium intake,” the study’s authors said.
They added that the study served as an early warning for humanitarian organisations and the agro-industry.
“Where soils cannot be manipulated to increase the long-term retention of Se, broad-scale micronutrient fertilisation may be necessary to maintain an adequate nutrient content in crops,” the study added.
Although they are needed in only trace amounts, inadequate dietary Se intake affects up to 1 in 7 people.
The European Food Safety Authority (EFSA) in 2014, set an Adequate Intake (AI) for selenium at 70 microgram (µg) per day for adults, and an AI of 15 µg/day for infants aged 7-11 months.
More about selenium
Selenium deficiency can contribute to Kashin-Beck disease that can eventually lead to weakening of the heart.
The condition can also cause the body to become more susceptible to illness caused by other nutritional or physiological disorders.
The condition is most prevalent in certain regions of China where the intake is low because the soil is deficient in selenium.
Studies have demonstrated a reduction in the prevalence of these conditions by taking selenium supplements.
In Finland, selenium salts were added to chemical fertilisers, as a method to increase selenium in soils.
Source: Proceedings of the National Academy of Sciences
Published online ahead of print: doi: 10.1073/pnas.1611576114
“Selenium deficiency risk predicted to increase under future climate change.”
Authors: Gerrad Jones, et al
