Lead is particularly dangerous when ingested by young children or pregnant women – it can impact the central nervous system and cause cognitive impairments or increase risks of miscarriages and premature births. To add to the detrimental effects, researchers from Stanford University, California, have recently presented evidence of increased lead exposure in rural Bangladesh, with its concentrations in turmeric exceeding the national limit by as much as 500 times.

While the production of spices, including turmeric, can bring about accidental lead contamination, some regions are susceptible to deliberate adulteration of the spice. Spice processors may choose to add an industrial lead chromate pigment to discolored turmeric roots as a cheap and quick way of giving it that characteristic yellow tinge.

This turmeric tampering was seen in seven of Bangladesh’s nine turmeric-producing regions, largely driven by consumer demand. However, the workers doing the polishing were unaware of the pigment’s neurotoxic effects. Stanford’s early investigations found that more than 30% of pregnant Bangladeshi women had elevated levels of lead in their blood. In some cases, the lead concentrations in the turmeric exceeded the national limit by up to 500 times, and were much higher than that reported in other studies.

Even if there is no clear evidence of the contaminated turmeric making its way beyond Bangladesh, current food safety checks “may catch only a fraction of the adulterated turmeric being traded worldwide.”

Hence, the researchers are advocating for measures to lessen turmeric adulteration through new and improved processing techniques. They also call for import inspectors to be equipped with X-ray devices for lead-detection at global trade centres.