Bromine and Fluorine: Thyroid Disruption

The CR Mardi Gras was so much fun! It’s wonderful to see CR Way practitioners who actually look younger than when we saw them almost a year ago. As usual, this CR Way party was filled with enriching conversations.

Certainly one of them was with our good friend, Anthony, who brought up concerns about bromine (bromide, bromate), displacing iodine in the thyroid and thus causing thyroid malfunction. Anthony reminded us that bromine is a halogen – the same family of elements as fluorine, chlorine, and iodine. Bromine is more reactive than iodine, so in the body, bromine might end up binding to cellular receptors usually used by iodine.

That would have profound health consequences because iodine plays leading roles in tissues and organs throughout the body. So, thank you, Anthony, for your logical and well supported ideas about bromine.

He also described bromine’s use in pesticides (which end up in vegetables) and breads (used as a “bread improver,” which gives the bread bigger volume and better shape – other bread improvers are available, e.g., ascorbic acid. Regulators have begun to consider bromine’s potential danger, and millers and bakers have begun switching even though it changes the timing of their processing). As we began to research it, we found bromine sources everywhere – plastics, medications, and polluted air for example. The good news is that most CR Way travelers do not eat some of the worst bromine-containing foods like soft drinks and baked goods with bromine added.

An EPA assessment of bromine in medicines indicates that it is well tolerated, but that is not reassuring if it has a long-term effect of occupying receptors that iodine “should” be using to benefit our good health. In fact, research has established that if your iodine intake is low to moderate (like most people), bromine will interfere with production of  thyroid hormones:


Effects of sodium bromide on the biosynthesis of thyroid hormones and brominated/iodinated thyronines.

Journal of Trace Elements and Electrolytes in Health and Disease. 1990 Mar;4(1):25-30.

Buchberger W, Holler W, Winsauer K.

Paracelsus-Institut, Chemische Abteilung, Bad Hall, Austria.



The influence of bromide on thyroid function was studied in iodine-deficient rats, fed on a diet containing 4-16 g/kg sodium bromide for 4 weeks.

Measurement of total and free thyroxine and thyroid-stimulating hormone in blood, as well as the thyroid hormones in the thyroid gland, revealed typical signs of hypothyroidism, which were significantly enhanced by bromide intake. Special attention was paid to the possible formation of bromo/iodosubstituted thyronines in the thyroid. These measurements were performed by high-performance liquid chromatography with off-line radioimmunoassay detection. Such thyroid hormone analogues could be detected in all groups of animals with additional bromide intake, but the amounts were found to be too low to compensate adequately for the reduced amounts of thyroid hormones. The results of this study also indicate that bromide toxicity is dependent upon the state of the iodine supply, which should be taken into account for evaluation of acceptable daily intake values for bromide.

PMID: 2135954, NIH, NLM, PubMed access to MEDLINE citations


On the way home from the CR Mardi Gras we also wondered about fluorine, which is even more reactive than bromine. Wouldn’t fluorine be as bad as or worse than bromine? Could fluoridated water contribute to an unhealthy thyroid and  result in a cascade of other problems? The research results were even worse than expected, for example:

Fluoride toxicity and status of serum thyroid hormones, brain histopathology, and learning memory in rats: a multigenerational assessment.

Biological Trace Elements Research. 2011 Dec; 144(1-3):1083-94.

Basha PM, Rai P, Begum S.

Department of Zoology, Bangalore University, Bangalore, 560 056,


High-fluoride (100 and 200 ppm) water was administered to rats orally to study the fluoride-induced changes on the thyroid hormone status, the histopathology [the study of the microscopic anatomical changes in diseased tissue] of discrete brain regions, the acetylcholine esterase activity, and the learning and memory abilities in multigeneration rats. Significant

·         decrease in the serum-free thyroxine (FT4) and free triiodothyronine (FT3) levels and

·         decrease in acetylcholine esterase activity [disabling the cholinergic signaling, which is important in both peripheral nerves and the central nervous system: think memory!]

in fluoride-treated group were observed.

·         Presence of  [all of the following examples of brain deterioration and damage:]

o   eosinophilic [readily stained with acidic dyes such as eosin]  Purkinje cells [neurons of the brain’s cerebellar cortex],

o   degenerating neurons,

o   decreased granular cells, and

o   vacuolations [vacuoles – small cavities or spaces in tissue, especially in nervous tissue as the result of disease]

were noted in discrete brain regions of the fluoride-treated group.


In the T-maze experiments,

·         the fluoride-treated group showed poor acquisition and retention and higher latency when compared with the control.

·         The alterations were more profound in the third generation when compared with the first- and second-generation fluoride-treated group.

Changes in the thyroid hormone levels in the present study might have imbalanced the oxidant/antioxidant system, which further led to a reduction in learning memory ability. Hence, presence of generational or cumulative effects of fluoride on the development of the offspring when it is ingested continuously through multiple generations is evident from the present study.

PMID: 21755305, NIH,NLM, PubMed access to M EDLINE citations

This is serious. We will discuss this and the new How to Avoid Thyroid Disruptors page on tonight’s  (February 29, 2012) teleconference. The page and the teleconference are accessible to full members.

For a start, a good strategy may be to include an iodine source in your diet that approaches the RDA of 150 mcg. on most days of the week. Please note that excessive iodine intake can also artificially depress thyroid hormones. For this reason, daily intake of iodine may not be optimal. Any artificial reduction of thyroid function by bromine or fluorine interferes with the true assessment of whether your thyroid is healthfully lowered because of following the CR Way and may seriously damage your health.

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