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Herbal Products and Lead

A study of 12,807,women of childbearing age between 199-2004 taking herbal supplements were tested.

Women taking echinacea, ginkgo, ginseng and St. John's wort had their blood tested and results found some patients with high levels of heavy metal including lead and some patients with lead toxicity. Since wide spread use of the above herbs in U.S. as alternative medicine, elevated blood lead levels are of concern.

1.  Since benefits of herbal supplements in this study are largely unproven, the potential for harm from their use may be greater than the benefit, especially in women who could prenatally expose fetuses to lead, said Dr. Buettner of Harvard Medical School, Boston.

2.  The list included echinacea, ginkgo, ginseng, St. John's wort, "traditional" herbs such as those used in Ayurvedic medicine or traditional Chinese medicine, and, less commonly, others such as kava, valerian, black cohosh, bee pollen and nettle.

3.  In a subanalysis of women aged 16-45 years, those who used any of the herbal supplements had lead levels 20% higher, ranging from 10% to 40%, depending on the specific supplement, compared with women who did not use them. Lead levels of 10mcg/dL or above the current public health threshold of concern were seen in just 0.6% of the entire cohort, to few to determine differences between supplement users and nonusers above that threshold. However, that threshold has become controversial in recent years, Dr. Buettner said in a follow-up interview.  Indeed, increasing evidence suggests that adverse health effects may actually occur at far lower levels.  For example, a study involving 172 children aged 3-5 years showed declines in IQ of 7.4 points as lifetime average blood lead concentrations increased from 1 to 10 mcg/dL (N. Engl. Med. 2003;348:1517-26).  In another, blood lead levels below 10 mcg/dL measured in a nationally representative sample of 13,946 adults followed for 12 years were significantly associated with both myocardial infarction and stroke mortality, with the association evident at levels above 2mcg/dL (Circulation 2006;114:1388-94).  Dr. Buettner's data suggest a dose-response relationship between lead levels below 10mcg/dL and peripheral neuropathy.


June 08