[R.B.]

A question that has been bothering me for a while is does chlorine in forms other than perchlorate block iodine uptake and or thyroid function.

This paper which I found after several hours searching (in total) suggests it might well do so.

Mechanistic Aspects of Ingested Chlorine Dioxide on Thyroid Function: Impact of Oxidants on Iodide Metabolism

Environmental Health Perspectives
Vol. 69, pp. 249-255, 1986

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1474311/

"Toxicological studies dealing with recent findings of health effects of drinking water disinfectants are
reviewed. Experiments with monkeys and rodents indicate that the biological activity of ingested disinfectants is expressed via their chemical interaction with the mucosal epithelia, secretory products, and nutritional contents of the alimentary tract. Evidence exists that a principal partner of this redox interaction is the iodide of nutritional origin that is ubiquitous in the gastrointestinal tract. Thus the observation that subchronic exposure to chlorine dioxide (CI02) in drinking water decreases serum thyroxine levels in mammalian species can be best explained with changes produced in the chemical form of the bioavailable iodide. Ongoing and previously reported mechanistic studies indicate that oxidizing agents such as chlorine-based disinfectants oxidize the basal iodide content of the gastrointestinal tract. The resulting reactive iodine species readily attaches to organic matter by covalent bonding. Evidence suggests that the extent to which such iodinated organics are formed is proportional to the magnitude of the electromotive force and stoichiometry of the redox couple between iodide and the disinfectant. Because the extent of thyroid uptake of the bioavailable iodide does not decrease during C102 ingestion, it seems that C102 does not cause iodide deficiency of sufficient magnitude to account for the decrease in hormonogenesis. Absorption of one or more of iodinated molecules, e.g., nutrients, hormones, or cellular constituents of the alimentary tract having thyromimetic or thyroid inhibitory properties, is a better hypothesis for the effects seen."


They confirm that "The most surprising observation in our studies was that chlorine dioxide is a relatively potent thyroid inhibitor, showing clear physiologic effects at about 9 mg/kg/day dose in 11 of 13 animals studied (1)."


A WHO document suggest chlorinated water contains about 1 mg per litre but it seems the allowable amount is up to 15mg per kg of body weight per day - so the amount in your water would depend on your local provider water quality etc.

This is scary in its potential implication where significant amounts of chlorine dioxide are present in water mainly because we know so many are already low in iodine, because it is them who are generally affected by and at significant risk from iodine blockers in their generality.

Blockers also include brassicas, many soy products, and something found in water in varying concentration called perchlorate, fluoride and bromide. Fluoride is put in water as well as some toothpaste, and in the USA bromide is it seems is often put in bread and in some popular drinks.

Both flouride and bromide are found in seawater and so marine organisms, which again points to the problem at heart being lack of iodine.

The paper suggests that what ever is causing the iodine blocking is likely to be something made in the mouth or upper intestinal tract by reaction with the chlorine, rather than the chlorine alone itself. Iodine has important roles in the mucal tissues including the salivary duct. What other effects these alterations of natural processes have we do not know.

Some have asked why we do not use iodine to 'purify' water they suggest solving two problems at once. Apparently it was tried in a prison with no harm to the population, I presume a very long time ago !