The relationship between supplements and lead levels in blood has been an ongoing project for researchers in Boston.

In this study, researchers from Beth Israel Deaconess Medical Center report specific herbal supplements are associated with higher blood lead levels among women.

First, the details.

  • Lead blood levels were measured in a sample of adults who participated in the National Health and Nutrition Examination Survey (NHANES).
    • Findings from the NHANES surveys are used to determine the prevalence of and risk factors for major diseases.
  • Associations between lead and self-reported supplement use were estimated.
  • Herbal supplements investigated were those previously reported to contain high heavy metal content:
    • Ayurvedic or traditional Chinese medicine herbs
    • Echinacea
    • Ginkgo
    • Ginseng
    • St. John’s wort
    • “Other” herbs (kava, valerian, black cohosh, bee pollen, and nettle).

And, the results.

  • Among 6712 women who used herbal supplements, lead levels were 10% higher than in non-users — a significant difference.
  • Women using Ayurvedic or traditional Chinese medicine herbs, St. John’s wort, and “other” herbs had lead levels between 21% and 24% higher than non-users — a significant difference.
  • There was no association between herb use and lead levels among men.
  • Among reproductive-aged women (16-45 years), herbal supplement users had lead levels 20% higher than non-users — a significant difference.
  • In contrast, garlic and other dietary supplements were not associated with higher lead levels.

The bottom line?
The authors concluded, “Testing guidelines for herbal supplements and regulations limiting lead in supplements are needed.”

In contrast to these findings, the prevalence of elevated blood lead levels among children and women in the United States, like that in the general population, has declined sharply during the past decade.

This study builds on earlier research that showed 1 of 5  Ayurvedic herbal medicines produced in South Asia and available in Boston South Asian grocery stores contain potentially harmful levels of lead, mercury, and/or arsenic.

In another study of Ayurvedic medicines, “One-fifth of both US-manufactured and Indian-manufactured Ayurvedic medicines purchased via the Internet contain detectable lead, mercury, or arsenic.”

In a third study, researchers reported, “Compared to the patients with lead paint exposure, the Ayurvedic patients [with lead poisoning] on average presented [to the emergency room] with significantly higher blood lead levels and greater effects on blood cells.”

A list of studies and reports since 2006 on the risk of heavy metal poisoning associated with Ayurvedic medicines is here.

With regard to other herbals, search the ConsumerLab website for the results of quality control studies of herbals. Their reports often include the results of lead analysis.

7/4/09 19:02 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.