After examining how soy, peanuts/cashews, smoking, bromide, and pesticides inhibit iodine/thyroid function, let's now examine another prevalent, powerful iodine usurper: fluoride!
Many writers in previous decades have tried to sound the alarm about fluoride. Many believed that there was a conspiracy to add fluoride to the water supply to "dumb down" the nation.
There is certainly much evidence linking fluoride with lower intelligence and I.Q. scores:
“…children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas…The results support the possibility of an adverse effect of high fluoride exposure on children's neurodevelopment…”
(Environ Health Perspect. 2012 Oct)
“As of June 2018, a total of 60 studies have investigated the relationship between fluoride and human intelligence, and over 40 studies have investigated the relationship fluoride and learning/memory in animals. Of these investigations, 53 studies have found that elevated fluoride exposure is associated with reduced IQ in humans, while 45 animal studies have found that fluoride exposure impairs the learning and/or memory capacity of animals.”
One of the chief ways that fluoride hinders brain function is by competing for iodine in the body. Flouride was once used for the purpose of suppressing thyroid function!:
“Thyroidal, blood and urinary radioiodine studies suggest that fluorine inhibits the thyroid iodide-concentrating mechanism…"
(Journal of Clinical Endocrinology, 1958)
“Goldemberg publishes extensively between 1921 and 1935 on his findings of applying fluorides as anti-thyroid medication…1927 - Gorlitzer von Mundy (Austria) reports that daily intake of 3 mgs of fluoride in rabbits and rats leads to goiter and cretinism-like conditions…1934 - Chang, Phillips, et al. report that in the thyroid of cows fed fluoride for a long time, the fluoride content increased to 240 times as much…1944 - The editorial in the Journal of the American Dental Association (JADA) acknowledges that '...drinking water containing as little as 1.2 to 3ppm of fluorine will cause such developmental disturbances...as goitre'. 1944 - Shrewsbury et al. document toxic effects of fluoride on the thryoid of sheep…1948 - Steyn (Africa) finds that fluoride has definite anti-thyroid effects…1972 - Willems et al. document that sodium fluoride blocks thyroid hormone secretion…” (http://poisonfluoride.com/pfpc/html/thyroid_history.html)
“As early as 1928, Stocks (1928) observed that children consuming well water in the village of Somerset, England exhibited both goiter and mottled enamel (dental fluorosis). Some years later, Wilson (1941) found dental fluorosis (DF) associated with goiter and cretinism among children living in areas of Punjab where fluoride was recognized geologically to be significantly high. Besides dental fluorosis and cretinism, children in endemic fluorosis areas of India often have low IQ…Since fluoride is known to interfere with thyroid gland function and to cause degenerative changes in the central nervous system, impairment of brain function and abnormal development in children (Ha et al. 1989), further investigation is clearly needed, even where iodine intake is not deficient…As it is already known that fluoride is more electronegative than iodine, it easily displaces iodine within the body, thereby affects the functioning of thyroid gland. Fluoride has been known to have shown gross as well as biochemical changes within the body of an individual which included deranged thyroid hormonal level with in the body…Fluoride and iodine are both halogens. The fluoride, the negative ion of the element fluorine easily displaces iodine in the body because it is much lighter and therefore more reactive…fluoride-thyroid-iodine antagonism...[leads] to interference with iodine uptake…Fluoride competes for the receptor sites on the thyroid gland…The results of this study question the validity of the fluoridation of drinking water, milk, fruit juices, and salt by public health authorities…”
(Springerplus. 2014; 3: 7.)
"A consistent body of animal and human research shows that fluoride exposure worsens the impact of an iodine deficiency. Iodine is the basic building block of the T3 and T4 hormones and thus an adequate iodine intake is essential for the proper functioning of the thyroid gland. When iodine intake is inadequate during infancy and early childhood, the child’s brain can suffer permanent damage, including mental retardation…In China, researchers have repeatedly found that an iodine deficiency coupled with fluoride exposure produces a significantly more damaging effect on neurological development than iodine deficiency alone…In the first study to investigate the issue, Ren reported that: 'From the results it is evident that disrupted child intellectual development is among the effects on the human body from a harmful environment containing both high fluoride and low iodine, and this disruption is clearly much more serious than the effects of iodine deficiency alone.' [SOURCE: Ren D, et al. (1989). A study of the intellectual ability of 8-14 year-old children in high fluoride, low iodine areas. Chinese Journal of Control of Endemic Diseases 4(4):251 (republished in Fluoride 2008; 41:319-20).]" (http://fluoridealert.org/studies/thyroid01/)
"In 1991, a UNICEF-funded study concluded that fluoride levels of just 0.9 ppm (less than the level added to many water supplies for fluoridation) were sufficient to worsen the effects of iodine deficiency. The authors found that, when compared to children with iodine deficiency in a low-fluoride area, the children with iodine deficiency in the 0.9 ppm area had increased TSH levels, reduced T3, reduced intelligence, retarded bone development, and reduced hearing. According to the authors: 'Statistically significant differences existed between these areas, suggesting that a low iodine intake coupled with high fluoride intake exacerbates the central nervous lesions and the somatic developmental disturbance of iodine deficiency.' [SOURCE: Lin Fa-Fu; et al (1991). The relationship of a low-iodine and high-fluoride environment to subclinical cretinism in Xinjiang. Endemic Disease Bulletin 6(2):62-67 (republished in Iodine Deficiency Disorder Newsletter Vol. 7(3):24-25).]"
"In 1994, Xu and colleagues measured the IQ rates of children living in 8 areas with differing levels of both iodine and fluoride in exposure. Of all the areas studied, the region with the high fluoride/low iodine content had the lowest IQ…In 2004, Wang and colleagues reported that: 'In comparison with control rats, the learning and memory ability of the offspring rats was depressed by high fluoride, low iodine, or the combination of high fluoride and low iodine. Brain protein was decreased by low iodine and even more by the combined interaction of high fluoride and low iodine. The activity of cholinesterase (ChE) in the brain was affected to some extent by high fluoride and low iodine but was especially affected by high fluoride and low iodine together.' [SOURCE: Wang J, et al. (2004). Effects of high fluoride and low iodine on biochemical indexes of the brain and learning-memory of offspring rats. Fluoride 37(4): 201-208.]"
"In an animal study by Guan (1988), fluoride's effect on thyroid function occurred at lower doses, and was more severe, when the animals (rats) had an iodine deficiency. Similarly, the effects of iodine deficiency were more severe with fluoride exposure, than without...In addition to Guan's study, an animal study by Zhao et al (1998) found that fluoride and low iodine have 'mutually interacting effects' on the thyroid gland…Over the past few decades, the rate of iodine deficiency has increased in the United States…"
Fluoride is not a nutrient! And most children are exposed to dangerous levels of fluoride:
“A single strip of toothpaste covering the length of a child’s brush contains between 0.75 to 1.5 mg of fluoride. This exceeds the amount of fluoride in most prescription fluoride supplements (0.25 to 1.0 mg).”
"Today, fluoride is everywhere from the drinking water, to non-stick pans, toothpastes and many medications. It is estimated that the average American takes in somewhere between 1.6 to 6.6 mg/day of fluoride each day…Research in the fifties showed that all it took to suppress the thyroid was 2-5 mg of fluoride per day for a couple of months…In the past 30 years, iodine levels have decreased by 50% in the general population…Iodine deficiency may be the major reason why the thyroid is so vulnerable to environmental toxins…In numerous studies, iodine supplementation has been found to significantly increase in the urinary detoxification of both fluoride and bromide…In one study, only one day after supplementing with 50 mg of iodine, urinary excretion of bromide increased by nearly 50% and fluoride excretions increased by 78%...[https://www.ncbi.nlm.nih.gov/pubmed/11275672/, etc.]…Research has indicated that the current RDA for iodine, at 150 mcg per day, may be too low…Many folks who have a 'normal' TSH test are actually found to have low T3 or T4 thyroid hormone levels…There are many factors that can cause poor thyroid function. Perhaps the most dangerous to normal thyroid function: fluoride!"
(John Douillard, June 27, 2017)