More heavy metals in dietary supplements

Via Terra Sigilatta (who beat me to this one, as I saw the press release yesterday but never got around to blogging about it), we find yet another case of heavy metal contamination of a popular supplement, this time herbal kelp supplements. This discovery was prompted by the investigation of a case of woman who suffered real harm from these supplements:

The new study, published in this month’s issue of Environmental Health Perspectives – available online at – was prompted by the case of a 54-year-old woman who was seen at the UCD Occupational Medicine Clinic following a two-year history of worsening hair loss, fatigue and memory loss.

The woman’s symptoms had begun with minor memory loss and fatigue. Her primary care physician initially found nothing wrong with the woman and thought the symptoms were related to menopause. With no specific diagnosis or treatment recommendations, the patient started taking a variety of herbal therapies, including a kelp supplement, fish oil, ginkgo biloba and grape seed extract. The kelp supplement was the only herbal therapy she took regularly throughout the course of her illness.

Over a period of several months, the woman’s short- and long-term memory became so impaired that she could no longer remember her home address. She also reported having a rash, nausea and vomiting, which made it very difficult to work and forced her to leave a full-time job. The woman actually increased her dosage of kelp from two to four pills a day after her doctors still could not find a clear diagnosis.

Bad move, because this is why the woman was having problems:

A study of herbal kelp supplements led by UC Davis public health expert Marc Schenker concludes that its medicinal use may cause inadvertent arsenic poisoning and health dangers for consumers, especially when overused.

Schenker and two researchers evaluated nine over-the-counter herbal kelp products purchased at Davis stores and found higher-than-acceptable arsenic levels in eight of them.

Names of the brands and stores were not released. Schenker said the samples were tested in a blind study, meaning the samples were not labeled so researchers did not know which brand or store each sample was from.

Further, Schenker said the arsenic levels appear to vary from batch to batch. So, a brand that appears safe in one batch may have high arsenic levels in another.

(Link to original study)

Why the hell didn’t they release the brand names of the kelp supplements with the excessively high levels of arsenic in them? In a blinded study, even a blinded clinical study, there is an investigator who can break the code and unblind the experimental groups to reveal which one is which. The specific brands and lots that were contaminated should have been published in the paper! The only reason I can think of for not publishing them is fear of legal action by the manufacturers. Be that as it may, the woman’s kelp supplements contained 8.5 ppm arsenic, with FDA recommendations being no more than 0.5-2.0 ppm for certain food products. Here are the symptoms of chronic arsenic poisoning, as described in the article:

Chronic arsenic toxicity may cause peripheral neuropathies, parasthesia, ataxia, cognitive deficits, fatigue, and muscular weakness. GI complaints include anorexia, hepatomegaly, jaundice, nausea, and vomiting. Skin afflictions may include erythema, eczema, pigmentation (arsenic melanosis), diffuse alopecia, keratosis (especially of palms and soles), scaling and desquamation, brittle nails, white lines or bands in the nails (Mees lines), and localized subcutaneous edema. White striae in the fingernails are consistent with a diagnosis of arsenical polyneuritis, even though urine and hair arsenic concentrations may be within normal limits (Heyman et al. 1956).

Manifestations of chronic arsenic ingestion depend on both the intensity and duration of exposure. Our case had a more severe presentation than would be expected with an elevated urinary arsenic concentration of 83.6 μg/g creatinine. The intensity of her symptoms may have been the result of her lengthy duration of exposure or perhaps of an undiagnosed underlying condition. Also, that a single spot urine may not be as accurate as a 24-hr urine sample, despite adjustment for creatinine concentration.

And this is far from the only example of such problems:

A number of published studies have highlighted cases in which homeopathic remedies cause clinical arsenic toxicity. One such study describes 74 patients in Singapore who were victims of chronic arsenic poisoning caused by local antiasthmatic herbal preparations (Tay and Seah 1975). Systemic involvement mainly affected the patients’ skin (hyperpigmentation, hyperkeratosis), nervous system (polyneuropathy, tremors, headache), and GI system (gastroenteritis, toxic hepatitis). Of the 74 patients studied, 10 presented with malignancies. Of the 29 herbal preparations analyzed in this study, 16 contained inorganic arsenic in concentrations of 25-1,000 ppm, and 10 contained 1,001-50,000 ppm.

Mitchell-Heggs et al. (1990) reported on a 33-year-old Korean woman who presented with malaise, difficulty walking, arthralgia, and diarrhea. Her elevated urine and blood arsenic levels were linked to an herbal treatment for hemorrhoids, which contained 10,000 ppm arsenic. The patient recovered completely after ceasing her usual dosage of 90 pills/day (50 mg/day).

Espinoza et al. (1995) analyzed traditional Chinese herbal balls, which are taken for a variety of conditions, including rheumatism and cataracts. The herbal balls were found to contain up to 36.6 mg arsenic per ball. The authors concluded that with a “recommended dose” of two herbal balls daily, the preparation “poses a potentially serious health risk to consumers.” They advised that “health professionals should be aware that patients who consume traditional Chinese remedies may be exposed to potentially toxic substances” (Espinoza et al. 1995).

Fortunately, the story that prompted this study has a happy ending:

At her physician’s suggestion, the patient discontinued the kelp supplement. Within weeks, her symptoms disappeared, and within several months arsenic was no longer detected in her urine and its levels had dropped significantly in her blood.

She later was referred to the UCD Occupational Medicine Clinic as a follow-up to her primary care.

When I say that I want to see “alternative” medicines treated the same way as “conventional” medicines, cases like this one are another reason why.