Health researchers have called for enhanced regulatory scrutiny of turmeric in south Asia after they detected evidence of what they suspect was “intentional adulteration” of turmeric with toxic lead chromate pigment in samples from seven cities, including three in India.
The researchers at Stanford University in the US have found lead levels that exceeded India’s standard limit of 10 micrograms per gram in 24 (7 per cent) of 356 turmeric samples from Patna, Guwahati, Chennai, Islamabad, Karachi, Peshawar and Kathmandu, among 23 cities surveyed.
Each of the 12 turmeric samples analysed from Patna contained lead, with a median-average lead concentration of 1,200 micrograms per gram, 120-fold higher than the limit set by the Food Safety Standards Authority of India (FSSAI), the country’s apex food regulatory authority.
Among samples from 17 Indian cities, lead concentrations exceeded the FSSAI limit in 11 of 12 samples in Patna, two of 18 samples in Guwahati, and one of 19 samples in Chennai. Lead concentrations were within the limit in all the samples from the other 14 cities.
The study was based on samples collected between December 2020 and March 2021 but its findings remain relevant because ongoing research findings indicate that intentional adulteration continues, said Jenna Forsyth, an environmental health scientist who led the study.
“Even 7 per cent translates into a large population affected given that this was a snapshot of big cities across south Asian countries,” Forsyth, who is studying lead exposure in south Asia, told The Telegraph via email. “Lead has no physiological purpose and is toxic to every system in the body.”
Long-term lead exposure can impair brain function, leading to cognitive decline, or impaired intellect. The researchers have used modelling calculations to estimate that children exposed to lead levels found in turmeric samples in Bihar would have IQ levels 7 points lower than unexposed children.
Not only children, adults too can be adversely affected by cognitive decline from lead exposure, by cardiovascular disease, renal failure and premature mortality from lead exposure, Forsyth said.
Turmeric is among the most common spices consumed daily in households across south Asia.
A chemical analysis of the lead-chromium ratio in the tainted samples indicates that the lead came from intentional adulteration of turmeric with toxic lead chromate pigments and not from the unintentional contamination of turmeric with polluted dust or soil, the researchers said.
The presence of lead chromate, albeit in a small proportion of turmeric samples, suggests that the practice of adding artificial colour has not been eliminated.
The FSSAI, which has issued public advisories in the past offering guidance to consumers on an easy, home-based test to detect lead chromate in turmeric, has not yet responded to an email query from this newspaper sent on Tuesday seeking its comments on the Stanford study.
The FSSAI also did not respond to a question asking how many, if any, turmeric samples had been tested for lead chromate by central or state authorities during 2021, 2022 and 2023 and whether the pigment had been found in any sample.
One sample in Patna had a lead concentration of over 2,274 micrograms per gram, more than 200 times higher than the limit set by the FSSAI. “Consuming turmeric at these levels would likely contribute to lead poisoning… particularly for children,” the researchers wrote in their study paper.
Long-term lead exposure can impair brain function, leading to cognitive decline, or impaired intellect. The researchers have used modelling calculations to estimate that children exposed to lead levels found in turmeric samples in Bihar would have IQ levels 7 points lower than unexposed children.
Not only children, adults too can be adversely affected by cognitive decline from lead exposure, by cardiovascular disease, renal failure and premature mortality from lead exposure, Forsyth said.
