It's billed as a health booster and healing agent, but according to a new study by the University of Stanford, turmeric contains lead compounds and may be the source of severe ailments.
Long banned from food products, lead is a potent neurotoxin considered unsafe in any quantity. According to the World Health Organization (WHO), lead increases the risk of heart and brain disease in adults and interferes with children's brain development.
Former studies showed elevating blood lead levels in Bangladesh, one of the world's predominant turmeric-growing regions. The new study, published in the Environmental Research journal, examined various potential sources of blood lead level contamination in Bangladeshis, and found that turmeric, a commonly used spice throughout South Asia, is the culprit.
Lead comes in various forms, called isotopes, and the ratios of those isotopes vary by the lead's origin. The researchers were able to fingerprint lead chromate-adulterated turmeric as the most likely culprit by matching it to lead isotopes in people's blood.
The adulterated turmeric issue dates back to the 1980s when a massive flood left turmeric crops wet and relatively dull in color. Demand for bright yellow curry led turmeric processors to add lead chromate, an industrial yellow pigment commonly used to color toys and furniture to their product. The practice continued as a cheap, fast way to produce a desirable color.
In a report released by the Stanford University, Lead author Jenna Forsyth wrote: "This problem can be solved in two ways: urging the producers to use more effective and efficient drying technologies for turmeric processing; and importing inspectors around the world screen turmeric with X-ray devices that can detect lead and other chemicals."
"The current system of periodic food safety checks may catch only a fraction of the adulterated turmeric being traded worldwide. It's a serious problem, as even the smallest amounts of lead should not be permissible," said Forsyth.
For his part, Author Stephen Luby, director of research for Stanford's Center for Innovation in Global Health, said: "It's a neurotoxin in its totality. We cannot console ourselves proposing that if the contamination were down to such and such level, it would have been safe."
