Read functional medicine or ancestral health websites blogs or print publications and you might come away with the impression that no one has healthy thyroid function these days. While the emphasis on thyroid dysregulation may be a bit overstated and perhaps even scare-mongering at times the undeniable truth is that there are in fact potentially millions of people living with suboptimal thyroid function. And considering the unpleasant—and in extreme cases debilitating—symptoms of a sluggish thyroid (such as depression chronic constipation fatigue weight gain and edema) it’s no wonder healthcare practitioners “in the know” prioritize optimizing thyroid function in their patients. People who had all but given up on ever feeling their best can go from “fat fuzzy and frazzled” to fabulous just by getting their thyroids back up to speed.

Unfortunately roadblocks to healthy thyroid function abound in the modern environment and food supply. Some of these are compounds that displace iodine in the body or make it more difficult for the thyroid gland to concentrate iodine. This can be the kiss of death for optimal thyroid health since iodine is a crucial part of thyroxine (T4 - 4 iodine atoms) and triiodothyronine (T3 - 3 iodine atoms). These compounds include other halogens—elements that fall in the same column (chemical group) on the periodic table. Among them are bromine fluorine and chlorine. Being in the same group means that these elements have similar properties when it comes to chemical bonding which may be problematic if a certain element fits inside the “lock” but fails to turn it and open the biochemical door.

The fluoridation of municipal water supplies has long been a controversial issue and it may have the unintended consequence of contributing to thyroid dysfunction. And considering the general guidelines for drinking plenty of water people may be getting more fluoride than they realize—and indeed more even than the federal government concluded is “necessary.” Due to a rising incidence in dental fluorosis the U.S. Department of Health and Human Services and the Environmental Protection Agency recommended a decrease in the amount of fluoride added to drinking water. The potential effect of high fluoride intake may be exacerbated in individuals who are starting from a place of iodine insufficiency which according to NHANES data is not an insignificant number of people. Many factors contribute to inadequate iodine intake but among individuals following a strict Paleo diet or those who aim simply to “eat clean” avoidance of dairy (a prime source of iodine in the modern diet) as well as favoring unrefined sea salt over use of iodized salt may mean that people who are otherwise following quite healthy diets could inadvertently become iodine insufficient. (Shellfish is an excellent source of iodine [as well as thyroid-critical selenium]; seaweed is a good option for vegetarians and vegans.)

Another halogen element that may interfere with healthy thyroid function is bromine. Bromine has been used in brightly colored soft drinks and sports beverages usually in the form of “brominated vegetable oil” (BVO). BVO helps to stabilize the coloring so it doesn’t separate from the water and other ingredients. (Its use is banned in Europe and Japan and it is not always specifically listed in the ingredients on food labels in the U.S. and Canada.) This compound may be problematic on its own but its effects might be compounded when we consider that these beverages may be displacing more nutritious foods in the diet—including iodine-containing milk.

Other dietary sources of bromine include bread and other products made from dough to which bromine has been added as a conditioner and stabilizer in the form of potassium bromate. Many manufacturers use potassium bromate in place of potassium iodate which was favored in the past and would have been a dependable source of iodine among those who eat bread regularly.

In addition to dietary sources bromine in the body may come from environmental exposure. Bromine is a primary constituent in flame-retardant fabrics upholstery furniture and more. These compounds called polybrominated diphenyl ethers (PBDEs) may accumulate in the body and cause endocrine disruption. Researchers have found that women with higher levels of PBDEs have greater incidence of thyroid dysfunction. The effect is stronger in post-menopausal women leading researchers to speculate that “the disruption of thyroid signaling by PBDEs may be enhanced by the altered estrogen levels during menopause.” According to one study’s lead author “These chemicals are just about everywhere from the blood in polar bears to eagles to humans on every continent. This near ubiquitous exposure means we are all part of a global experiment on the impact of endocrine disrupting chemicals on our bodies.” 

Another thyroid-offending compound is perchlorate found in fireworks vehicle airbag initiators matches signal flares and is naturally occurring in some fertilizers. According to the FDA perchlorate “can affect the functioning of the thyroid gland at sufficiently high doses. Perchlorate is present in some public drinking water systems and in some foods.”

The modern world certainly presents no shortage of challenges to optimal health and wellbeing. And while it’s impossible to completely avoid or eliminate all the risks healthcare practitioners may be able to help patients on their path to feeling better by digging deeper into diet and lifestyle issues they may not even be aware are adversely affecting them.