Bromine (Br)

Br – Bromine is a “halogen” related to iodine and is found in igneous rocks at 3.0 to 5.0 ppm; shale at 4.0 ppm; sandstone 1.0 ppm; limestone 0.2 ppm; fresh water 0.2 ppm; sea water 65 ppm; soil 5 ppm; marine plants 740 m (highest in brown algae); land plants 15 ppm; marine animals 60 to 1000 ppm; land animals 6.0 ppm; functions by brominated amino acids; strong evidence for essentiality for mammals.


Anke et al. (1988) reported that, when compared to goats fed 20 mg of bromine per kg diet, goats fed a diet containing

Bromine is one of the most abundant and ubiquitous of the recognized trace elements in the biosphere. It has not been conclusively shown to perform any essential function in plants, microorganisms, or animals. However, there are numerous findings that indicate the possible essentiality of bromine should be studied further. Bromide can completely replace chloride to support growth of several halophytic algal species and can substitute for part of the chloride requirement of chicks. A small significant growth response to dietary trace additions of bromide has been reported for chicks and mice fed a semisynthetic diet containing iodinated casein to produce a hyperthyroid-induced growth retardation.

In 1981, Oe et al. found unusually low bromide concentrations in serum and brain of patients subjected to chronic hemodialysis; apparently the artificial kidney removed bromine. They associated the insomnia exhibited by many hemodialysis patients with the bromine deficit. Subsequently, they did a double-blind trial in which either bromide or chloride was added to the dialysate of four patients on maintenance hemodialysis. Quality of sleep improved markedly in the two patients who received bromide but not in those who received chloride.

The findings of Oe et al. are not the first association between bromide and quality of sleep. Before barbiturates were used, doctors prescribed bromide for sleep. Many years ago, Zondek and Bier reported the possible presence of a bromine-containing sleep hormone in dog pituitary gland. A bromine-containing compound has been isolated from human cerebrospinal fluid, with properties corresponding to 1-methylheptyl–y-bromoacetoacetate (synonym of 2acetylbromoacetoacetate). This organic bromine compound has been shown to “provoke paradoxical sleep” when administered intravenously to cats.

All animal tissues contain 50-100 times more bromine than iodine, except the thyroid, where the reverse is true. Species differences in tissue bromine concentrations are small, and the element does not accumulate to any marked degree in any particular organ or tissue.

Most foods contained no more than a few micrograms of bromine per gram. An occasional grain or flour would contain a high level of bromine; however, bakery products made from those grains and flours contained no more bromine than other foods, and no occasional high value was seen. Furr et al. found four kinds of nuts relatively rich in bromine. In their analyses, almond, Brazil nut, English walnut, and pistachio contained 20, 87, 76, and 16 mcg bromine per gram dry weight, respectively.

As an ion in diets, bromine apparently has a low order of toxicity. Growing pigs tolerated 200 mcg/g, growing chickens tolerated 5000 mcg/g, and growing rats tolerated 4800 mcg/g without adverse effects.


J Trace Elem Electrolytes Health Dis 1990 Mar;4(1):25-30

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


Food Chem Toxicol 1983 Aug;21(4):391-404

Effect of sodium bromide on endocrine parameters in the rat as studied by immunocytochemistry and radioimmunoassay.
Loeber JG, Franken MA, van Leeuwen FX

Male rats were fed a normal or sodium bromide-enriched diet for 4 or 12 weeks. Sodium bromide concentrations were 0, 20, 75, 300, 1200 and 19,200 mg/kg diet. At the end of the experiments the pituitary gland, thyroid and testes were examined by histopathological and immunocytochemical techniques, while serum hormone levels were established by radioimmunoassay. Histopathological examination revealed an activation of the thyroid and a decreased spermatogenesis in the testes in the highest dose group. Using immunocytochemical techniques a decrease was noted in the amount of thyroxine in the thyroid. No effect was found in growth hormone-producing cells in the pituitary gland, while immunoreactivity for thyroid-stimulating hormone and for adrenocorticotropic hormone was increased. The concentration of thyroxine, testosterone and corticosterone in the serum appeared to be decreased. Due to feedback regulation, the pituitary gland was stimulated to produce and release thyroid-stimulating hormone, follicle-stimulating hormone, adrenocorticotropic hormone and insulin, whereas the release of growth hormone was suppressed. Most of these changes were restricted to rats on the highest treatment level. It is concluded that sodium bromide, at least in high doses, directly disturbs the function of the thyroid, testes and adrenals.