BENGALURU: A first-of-its-kind study led by the National Institute of Mental Health & Neuro Sciences (Nimhans) and King’s College, London, has indicated a worrisome possibility of arsenic affecting brain functions of children, adolescents and young adults even in regions in and around Bengaluru where arsenic presence in soil and water is found to be much lower than the known danger levels.
This is because the study found that even low exposure to arsenic, far below the thresholds set by the World Health Organization (WHO), can “alter” brain structures and impair cognitive abilities among the 6-23 age segment, making them more vulnerable to serious mental illnesses.
Arsenic, a naturally occurring toxic chemical element, is found in water, air, and soil in varying quantities. Long-term exposure to arsenic can cause cancer and skin lesions, and is associated with cardiovascular disease, diabetes and linked to negative impacts on cognitive development and increased deaths in young adults, according to the WHO. Arsenic-contaminated food, water and soil in which crops are grown, pose a grave threat to public health from arsenic.
The study found that the impact of exposure to low-level arsenic is not limited to people living in the flood plains and deltas of large river networks — such as the Indus, the Ganges-Brahmaputra-Meghna rivers, the Mekong, and the Red River, all of which have their origins from the arsenic laden rocks of the Himalayas — but has also been found in far-flung cities like Bengaluru.
The study, ‘The Consortium on Vulnerability to Externalizing Disorders and Addictions (cVEDA)’, was a multi-centre, population-based cohort study of over 9,000 children, adolescents and young adults in seven centres across India. “It discovered that minimal exposure to arsenic, far below the WHO threshold, during the developmental period (six to 23 years), can harm the development of brain structure and function and increase vulnerability to mental illnesses like schizophrenia, bipolar disorder, attention deficit/hyperactivity disorder, addiction among others,” said the study’s principal investigator Vivek Benegal, Professor, Psychiatry, Centre for De-addiction Medicine, NIMHANS.
Arsenic closely associated with dietary intake, particularly rice: Researchers
“The study found children and young adults in Bengaluru having greater difficulties in their brains than those living in the flood plains of the Himalayas because of the former’s rice eating habits,” said Benegal.
According to the researchers arsenic was found to be closely associated with dietary intake, particularly rice consumption. A naturally occurring chemical element arsenic may be found in food, including rice and some fish, due to its presence in soil or water.
It is not possible to remove arsenic entirely from the environment or food supply. “The detrimental effects of arsenic exposure were amplified by other risk factors such as malnutrition and poverty. Participants from economically disadvantaged backgrounds and those with a low body mass index (BMI) were identified as being at an increased risk of experiencing the negative effects of arsenic exposure.
The implications of the findings of the study are significant for public health policies and practices, especially in regions where rice is a dietary staple and socio-economic status is low, like many parts of Asia. Simple cooking methods to flush arsenic out of rice and low-cost filters for arsenic and iron from contaminated water are available but rarely used,” said the principal investigator.
He added: “These insights can offer policymakers and public health officials a fresh perspective on the risks tied to low-level arsenic exposure, assisting in the development and deployment of effective interventions.”
The research study is funded by the Indian Council of Medical Research and the Medical Research Council (UK) and published in the Journal of the American Medical Association (JAMA) and Network Open.