Hakala Research - Home where I had my testing done, also tests for bromide. I had both iodine and bromide tested. I was low in iodine, and high in bromide. When I retest, I expect to find that's I'm high in iodine and low in bromide, which will mean that iodine has kicked out the bromide. My diet during this time is consistant, I've been gluten free for 2 years, and totally grain free for 1 year.
From Hakala Labs Hakala Research - Home
"If the body is exposed to excess bromide, it can result in the bromide interfering with Iodine utilization in the body and creating a state of iodine deficiency.
While your body has receptors for and needs iodine to make thyroid hormone, there is no known physiologic usefor bromide in the body. When bromide binds to the iodine receptors in the thyroid gland, it disrupts the normal physiologic functioning of that gland.
The body is very slow at eliminating bromide. The normal half life of Bromide is 12 days and in cases of salt restriction and chronic bromide exposure, the half life of Bromide can be as high as 40-50 days.
People who ingest bromide may feel dull and apathetic and have difficulty concentration. Bromide also causes depression, headaches and irritability.
When iodine is deficient, the toxicity of bromide is accelerated.
Bromide toxicity may develop when bromide, acquired through environmental or dietary exposure causes bromide levels in the body to rise high enough to inhibit iodine utilization. Iodine supplementation will increase bromide excretion thereby reducing bromide toxicity."
This article from King Arthur Flour shows that potassium bromate used to condition bread dough is also a possible carcinogen, and has been banned in many countries. Bromate Fact Sheet - King Arthur Flour