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Case Reports
. 2007 Apr;115(4):606-8.
doi: 10.1289/ehp.9495. Epub 2007 Jan 18.

Case Report: Potential Arsenic Toxicosis Secondary to Herbal Kelp Supplement

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Case Reports

Case Report: Potential Arsenic Toxicosis Secondary to Herbal Kelp Supplement

Eric Amster et al. Environ Health Perspect. .
Free PMC article


Context: Medicinal use of dietary herbal supplements can cause inadvertent arsenic toxicosis.

Case presentation: A 54-year-old woman was referred to the University of California, Davis, Occupational Medicine Clinic with a 2-year history of worsening alopecia and memory loss. She also reported having a rash, increasing fatigue, nausea, and vomiting, disabling her to the point where she could no longer work full-time. A thorough exposure history revealed that she took daily kelp supplements. A urine sample showed an arsenic level of 83.6 microg/g creatinine (normal < 50 microg/g creatinine). A sample from her kelp supplements contained 8.5 mg/kg (ppm) arsenic. Within weeks of discontinuing the supplements, her symptoms resolved and arsenic blood and urine levels were undetectable.

Discussion: To evaluate the extent of arsenic contamination in commercially available kelp, we analyzed nine samples randomly obtained from local health food stores. Eight of the nine samples showed detectable levels of arsenic higher than the Food and Drug Administration tolerance level of 0.5 to 2 ppm for certain food products. None of the supplements contained information regarding the possibility of contamination with arsenic or other heavy metals. The 1994 Dietary Supplement Health and Education Act (DSHEA) has changed the way dietary herbal therapies are marketed and regulated in the United States. Less regulation of dietary herbal therapies will make inadvertent toxicities a more frequent occurrence.

Relevance to clinical practice: Clinicians should be aware of the potential for heavy metal toxicity due to chronic use of dietary herbal supplements. Inquiring about use of dietary supplements is an important element of the medical history.

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    1. Agency for Toxic Substances and Disease Registry 2006. Case Studies in Environmental Medicine: Arsenic Toxicity Standards and Regulations. Available: [accessed 26 February 2007].
    1. [Anonymous] 2002. Annual industry overview VII. Nutr Business Journal May/June:1–11.
    1. Bennett BG. Exposure of man to environmental arsenic—an exposure commitment assessment. Sci Total Environ. 1981;20(2):99–107. - PubMed
    1. Dietary Supplement Health and Education Act of 1994 1994. Public Law 103–417.
    1. Espinoza EO, Mann MJ, Bleasdell B. Arsenic and mercury in traditional Chinese herbal balls. N Eng J Med. 1995;333(12):803–804. - PubMed

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