Nitrates
Another suggestion that I had seen was that nitrate was a 'goitrogen' (used here and elsewhere in the loose sense that it affects thyroid function by inhibiting iodine metabolism in some way).
It appears they are likely goitrogens - and of particular significance in part because they are found in drinking water and so effect large parts of the population.
Logically the effect will be additive or maybe multiply goitrogenic effects of chlorination and fluoridation of water.
Nitrates are also used as food preservatives.
Not to forget organochlorines, and how little we know about the downstream effect of disinfecting foods with chlorine based products, (all those bagged salads, packaged veg fruit etc)
Then we have new foods such as soy products . . . to add to the foods we have long eaten which are goitrogens.
In moderation none of which individually would probably for most be a problem of significance for those with adequate iodine intake, but combined . . .
Disease by a thousand cuts it appears!
Our best intentioned additions to water and foods in our war against bacteria (which does not differentiate between friend and foe) may have tipped the balance all of which argues for a likely greater need of iodine; increased iodine may not be optimal but is surely better than all of the downstream possible consequences of deficiency.
Indian J Physiol Pharmacol. 2005 Jul-Sep;49(3):284-8.
Evaluation of possible goitrogenic and anti-thyroidal effect of nitrate, a potential environmental pollutant.
Mukhopadhyay S, Ghosh D, Chatterjee A, Sinha S, Tripathy S, Chandra AK.
Source
Endocrinology and Reproductive Physiology Laboratory, Department of Physiology, University of Calcutta, University College of Science and Technology, Kolkata.
"The overall results indicated the development of a relative state of functional hypothyroidism with enlarged thyroid after nitrate exposure. This study can explain a part for the persistence of residual goitre in the post-salt iodization phase."
Nitrate intake and the risk of thyroid cancer and thyroid disease.
Ward MH, Kilfoy BA, Weyer PJ, Anderson KE, Folsom AR, Cerhan JR.
Source
Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, National Institutes of Health, Rockville, MD, USA.
wardm@mail.nih.gov
BACKGROUND:
Nitrate is a contaminant of drinking water in agricultural areas and is found at high levels in some vegetables. Nitrate competes with uptake of iodide by the thyroid, thus potentially affecting thyroid function.
Increased thyroid volume and frequency of thyroid disorders signs in schoolchildren from nitrate polluted area.
Tajtáková M, Semanová Z, Tomková Z, Szökeová E, Majoros J, Rádiková Z, Seböková E, Klimes I, Langer P.
Source
Clinic of Internal Medicine, Faculty of Medicine, P.J. Safárik University, Trieda SNP 1, 040 66 Kosice, Slovakia.
It was concluded that long-term exposure to high nitrate intake by drinking water and home made meals from local products results in increased thyroid volume and increased frequency of signs of subclinical thyroid disorders (thyroid hypoechogenicity by ultrasound, increased TSH level and positive anti-TPO).
Comments on California’s Draft Public Health Goal for Perchlorate
February 23, 2011
http://www.google.com/url?sa=t&rct=j...AZ-E-vVD_oV2XA
My comments address a failure to account for ubiquitous exposure to
nitrate and thiocyanate, which have the same biological mode of action as
perchlorate, in setting the PHG. Potential perchlorate risks are unlikely to be
distinguishable from the ubiquitous background of other naturally occurring
substances present at much higher exposures that can affect the thyroid via the same biological mode of action as perchlorate, especially nitrate.