Seaweed and heavy metal contamination

[Guest guest]

Hi All,

 

Re: Kelp and Thrombocytopenia, Ihor wtote:

 

Hi Everyone: In researching autoimmune thrombocytopenia........I found

an interesting effect of Kelp that I had not known about. Have you?

 

Pye, Kathryn G., et al, Severe Dyserythropoiesis and Autoimmune

Thrombocytopenia Associated With Ingestion of Kelp Supplements. The

Lancet, June 20, 1992;339:1540. (Address: Kathryn G. Pye, Department

of Hematology, Royal London Hospital, London E1 1BB, United

KingdomIt is noted that kelp can concentrate heavy metals, and that

kelp preparations contain substantial levels of arsenic. It has been noted

that urinary arsenic excretion in patients with peripheral neuropathy, who

have been taking kelp tablets, has increased, and seaweed ingestion

has been linked with chronic thyroiditis. Arsenic intoxication can cause

bone marrow depression and megaloblastic changes. This is a case

report of a 54-year-old woman who had a 1 week history of abnormal

bleeding and petechiae. She had been taking vitamin and kelp tablets

for the previous 6 weeks. Three 550 mg kelp tablets daily with extra

calcium were consumed. The patient had widespread bruises and

petechiae but no other abnormalities. Her blood count was essentially

normal, but she had antiplatelet antibodies that were elevated. Serum

vitamin B12, folate, and direct antiglobulin tests were normal. Bone

marrow aspiration and trephine biopsies showed an increase in

megakaryocytes consistent with autoimmune thrombocytopenic

purpura. Erythropoiesis was grossly abnormal. Analysis of the kelp

tablets showed they contained 1.3 ug/d of arsenic. The patient

therefore had been ingesting 2.2 ug of arsenic/d. The kelp was

withdrawn and the autoimmune thrombocytopenia was treated with

intravenous immunoglobulin and prednisolone. There was a good

response. The authors believe that the kelp was responsible for the

severe dyserythropoiesis in this patient, and it may have been implicated

in either the pathogenesis of autoimmune thrombocytopenia or the

exacerbation of the pre- existing condition. The authors state that

physicians need to be aware of the potential dangers of contaminants in

some kelp preparations. 16295

 

[Other causes [of autoimmune thrombocytopenia] are: Reactions to

vaccines (measles-rubella); over supplementation with Fish Oils (heavy

metals?); over supplementation with B3 niacin; reaction to cow's milk,

and possibly other foods. Ihor ]

 

Ihor, I take the liberty of cross-posting this to CHA and TCM Lists

because you have raised an important question, IMO.

 

IMO, that article has little " scientific value " and its conclusions are

unjustified. But more on that anon ...

 

A Medline search for the profile (kelp or seaweed) AND heavy metal

gave 98 hits. See: http://tinyurl.com/a236o

 

Many seaweed species, including species used medicinally (for

example, Sargassum, Ecklonia, Fucus, Ascophyllum) scavenge heavy

metals, including Ag, As, Au, Cd, Cr, Hg, Pb, Zn. In polluted water, they

can accumulate these metals into their tissues. It follows that quality

control for heavy metals in seaweeds is important and that batches of

seaweed with unacceptably high levels of heavy metals should not be

used medicinally in oral form.

 

The article by Pye et al, above, described ONE patient who appeared to

respond to kelp withdrawal AND iv immunoglobulin and prednisolone.

There was no control. The latter two drugs also may have been effective

had the kelp NOT been withdrawn.

 

The abstract states: " The authors BELIEVE that the kelp was

responsible for the severe dyserythropoiesis in this patient ... [and state

that] ... physicians need to be aware of the potential dangers of

contaminants in some kelp preparations. "

 

I doubt if the arsenic content (estimated on analysis of the tablets to be

circa 2.2 ug/d) in that small kelp dose (1.65g/d) could be significant.

 

For example, Brown KG, Ross GL; American Council on Science and

Health.Arsenic, drinking water, and health: a position paper of the

American Council on Science and Health. Regul Toxicol Pharmacol.

2002 Oct;36(2):162-74. Kbinc, Chapel hill, North Carolina 27516, USA.

say: " ACSH concludes that there is little, if any, evidence of a

detrimental health effect in humans from inorganic arsenic in drinking

water at the current maximum contaminant level (MCL) of 50 microg/L

or below, either in the United States or elsewhere. "

 

Adult humans drink 1-3L water/d. Therefore, according to ACSH,

intakes of 50-150ug As/d should NOT be detrimental to health. One

must wonder how Pye et al could attribute the problem to 2.2ug As/d.

IMO, this is highly speculative and very poor science. It certainly does

not PROVE that the kelp dose or its arsenic load CAUSED the problem.

Nevertheless, it will be cited in future against phytotherapy.

 

The US-NRC recommends maximum of 1mg iodine/d as safe for adult

humans. [ http://homepage.eircom.net/~progers/tahip/i_report.htm#mi ]

On the other hand, sargassum is dosed medicinally at up to 20g/d

according to some authors. Such high seaweed doses could add

excess IODINE, as the iodine content in dried seaweed can be 600-

6000+ mg/kg (i.e. 12-120mg I in 20g). Even 12mg iodine/d is a grossly

excessive iodine intake for humans, especially if taken at that dose for

weeks on end. That dose would be likely to cause thyrotoxicosis, at

least in some people..

 

 

 

 

 

Best regards,

 

 

Tel: (H): +353-(0) or (M): +353-(0)

 

 

 

 

Ireland.

Tel: (W): +353-(0) or (M): +353-(0)

 

 

 

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