The RDA established for iodine is based on the minimum daily amount needed to prevent goiter, supposedly 0.15 mg/day (150 mcg/day). Goiter is the enlargement of the thyroid in response to extremely low iodine intake.
Iodized salt is the government's mainstay for prevention of goiter, therefore anyone who is not using adequate amounts of iodized salt in his diet will most likely be deficient in iodine because iodine occurs in such small quantities in food. Even though the USA is considered an iodine-sufficient nation by the bureaucrats, the USA is not in the least bit iodine sufficient. First of all, less than 50% of Americans use salt in their diets, and of the 50% who do, only half of them use iodinized salt. So how could the others who are not using the main goiter preventative (iodinized salt) really be iodine sufficient? Furthermore iodine is not evenly distributed in iodinized salt, and even the entire 1 pound Morton salt container only has, supposedly, 37 mg of iodine. Dr. Brownstein recommends 50 mg/day of iodine, not the insignificant 0.15 mg/day. The coastal Japanese have been taking the equivalent of 100 mg/day of iodine for thousands of years in the form of kelp. They have far fewer chronic diseases and cancers than the Japanese (and non-Japanese) living in the USA.
Since the thyroid gland is the most effective iodine-trapping organ in the body, the appearance of a goiter will be one of the very last signs of iodine deficiency. Before a goiter occurs there will likely be many other signs and symptoms of iodine deficiency such as fibrocystic breast disease, ovarian cysts, skin problems, atherosclerosis, elevated cholesterol levels, decreased mental status, depression, and fatigue.
Acta Endocrinol (Copenh). 1990 Dec;123(6):577-90. Iodine deficiency diseases in Switzerland one hundred years after Theodor Kocher's survey: a historical review with some new goitre prevalence data.Bürgi H, Supersaxo Z, Selz B. Medizinische Klinik, Bürgerspital, Solothurn, Switzerland.
In certain regions of Switzerland, before prophylaxis, 0.5% of the inhabitants were cretins, almost 100% of schoolchildren had large goitres and up to 30% of young men were unfit for military service owing to a large goitre.
Iodization of salt was introduced in 1922 at 3.75 mg I per kg and the iodine content was doubled twice, in 1962 and 1980, to the present 15 mg I per kg. In 1988, 92% of retail salt and 76% of all salt for human consumption (including food industry) was iodized, even though its use is voluntary. Urinary iodine excretion, previously between 18 and 64 micrograms per day, has now risen to 150 micrograms per day. No new endemic cretins born after 1930 have been identified. Goitre disappeared rapidly in newborns and schoolchildren, more slowly in army recruits, and incompletely in elderly adults. In some Cantons (by constitution in charge of health matters and the salt monopoly) which allowed iodized salt only in 1952, disappearance of goitre lagged behind accordingly, proof that iodized salt was the cause of regression.
The Swiss data provide evidence that isolated deafness, mental deficiency, and short stature, each without the other attributes of cretinism have also decreased. Adverse effects of iodized salt were minimal, possibly because the initial iodine content of salt was chosen very low. Iodization of salt has proved a highly cost-effective preventive measure in Switzerland.
In view of the fact that, during the first period of life, thyroid hormones are critical for brain development, we investigated whether even transient congenital hypothyroidism could affect the long-term intellectual development of affected infants.
DESIGN:
A case-control study of intellectual development, auxometric parameters and thyroid function performed in late infancy in children with documented transient congenital hypothyroidism or hyperthyrotrophinaemia at birth.
PATIENTS:
Nine children born in an endemic goitre area who had short-term transient congenital hypothyroidism or hyperthyrotrophinaemia after birth (TCH) were studied and compared to nine matched children born in the same area at the same time but having normal thyroid function at birth (N).
MEASUREMENTS:
Global, verbal and performance IQs were evaluated on the Wechsler scale. Height, bone age, total and free thyroid hormones, thyroid volume, thyroglobulin, basal and TRH stimulated TSH were also measured.
RESULTS:
Height and bone age were similar in the two groups. Thyroid function tests were also similar in the two groups except for basal and TRH stimulated serum TSH and serum Tg which were higher in the TCH than in the control group. Global, verbal and performance IQs were systematically lower in the TCH than in the N group. (78.3 +/- 11.1 vs 90.9 +/- 14.2, P < 0.05; 84.4 +/- 15.4 vs 96.2 +/- 14.8, P NS; 75.0 +/- 8.5 vs 89.2 +/- 12.5, P < 0.01 respectively).
CONCLUSION:
Infants born and living in an academic goitre area, who had biochemical signs of thyroid hypo-function at birth, had a lower intelligence quotient at the age of 7-8 years than matched controls living in the same environmental conditions but with normal thyroid function at birth. The present findings strongly suggest that abnormalities in thyroid function at birth, even when transient, can adversely affect long-term intellectual development.
Severe iodine deficiency still occurs in many countries, and causes cretinism and mental impairment. In southern Xinjiang province, China, after usual methods of iodine supplementation had failed, we iodinated irrigation water to increase iodine in soil, crops, animals, and human beings. 5% potassium iodate solution, dripped into an irrigation canal for 12 or 24 days, increased soil iodine 3-fold, and crop and animal iodine 2-fold. Median urinary iodine excretion in children increased from 18 to 49 micrograms/L (two groups of similar age). The cost for iodine was US $0.05 per person per year. Soil iodine remained stable over one winter, and dripping of iodine during the second year (US $0.12 per person per year) resulted in a further 4-fold increase in soil iodine and a 1.8-fold increase in iodine in crops. We conclude that iodination of irrigation water is an advantageous and cost-effective method of supplying iodine in southern Xinjiang, and may be useful in other areas dependent on irrigation. Med Hypotheses. 2008 Nov;71(5):645-8. Iodinedeficiency, more than cretinism and goiter. Verheesen RH, Schweitzer CM.Regionaal Reuma Centrum Z.O. Brabant, Máxima Medisch Centrum, Ds. Th. Fliednerstraat 1, 5631 BM, Postbus 90052, 5600 PD Eindhoven, The Netherlands. rh.verheesen@mmc.nl
Recent reports of the World Health Organization show iodinedeficiency to be a worldwide occurring health problem. As iodine status is based on median urinary iodine excretion, even in countries regarded as iodine sufficient, a considerable part of the population may be iodine deficient. Iodine is a key element in the synthesis of thyroid hormones and as a consequence, severe iodinedeficiency results in hypothyroidism, goiter, and cretinism with the well known biochemical alterations. However, it is also known that iodinedeficiency may give rise to clinical symptoms of hypothyroidism without abnormality of thyroid hormone values. This led us to the hypothesis that iodinedeficiency may give rise to subtle impairment of thyroid function leading to clinical syndromes resembling hypothyroidism or diseases that have been associated with the occurrence of hypothyroidism. We describe several clinical conditions possibly linked to iodinedeficiency, a connection that has not been made thus far. In this paper we will focus on the relationship between iodinedeficiency and obesity, attention deficit hyperactivity disorder (ADHD), psychiatric disorders, fibromyalgia, and malignancies. (2588-8-11; 2657-8-13; 3150-8-23; 5500-10-12; 6230-10-28; 6875-11-11; 8326-12-15; 9392-01-09; 10146-01-25; 11199-02-15; 14667-04-15)
