Halides & Your Thyroid: A Balancing Act
The thyroid is a small but mighty butterfly-shaped gland in your neck, responsible for regulating metabolism, energy, and overall hormonal balance. But did you know that its function can be significantly impacted by a group of elements called halides? Fluoride, chlorine, bromide, and iodine all belong to this family, but while iodine is essential for thyroid health, its chemical siblings can sometimes disrupt the gland’s delicate balance.
Want to learn more about the thyroid itself, what it does, and how to get testing? Check out my previous blog post on the thyroid here!
THE THYROID & IODINE: A CRITICAL RELATIONSHIP
Iodine is a non-negotiable nutrient for the thyroid. It’s the building block of thyroid hormones T3 and T4, which regulate everything from metabolism to brain function. In the past, iodine deficiency led to widespread goiter (thyroid enlargement), prompting the introduction of iodized salt in the early 1900s. This intervention largely solved the problem of goiter, but modern-day iodine concerns have taken a different turn.
Today, some people get too little iodine, while others may unknowingly disrupt their thyroid by consuming competing halides that block iodine uptake.
HALIDE COMPETITION: WHEN THE WRONG ELEMENTS TAKE OVER
Halides share similar chemical properties and can compete for iodine’s place in the thyroid. The problem? Some of these elements—fluoride, bromide, and chlorine—are now common in daily life, potentially interfering with thyroid health.
Fluoride: The Quiet Thyroid Suppressor
Fluoride was once used to treat hyperthyroidism because of its ability to slow down thyroid function.
Studies suggest that fluoride competes with iodine uptake, making it harder for the thyroid to produce hormones.
Most drinking water in the U.S. is fluoridated, and reverse osmosis (RO) filters are one of the only reliable ways to remove it.
Bromide: A Hidden Endocrine Disruptor
Found in bromated flour, certain sodas, and flame retardants, bromide is another iodine competitor.
Unlike iodine, bromide does not support thyroid function—it just takes up space, leading to potential thyroid dysfunction.
Some researchers question whether bromated flour contributes to non-celiac gluten sensitivity, making the case that gluten intolerance in the U.S. may be more about flour processing than gluten itself.
Chlorine: The Overlooked Contaminant
Found in tap water, swimming pools, and cleaning products, chlorine exposure is nearly unavoidable.
While the body can handle some chlorine, excess exposure may disrupt iodine absorption and contribute to thyroid imbalances.
The good news? Most shower filters can effectively remove chlorine, reducing exposure through skin and inhalation.
WHY IS OUR WATER FLUORIDATED?
Fluoridation of water began in the 1940s as a public health effort to reduce tooth decay, but emerging research has questioned whether the benefits outweigh the risks. Fluoride was once used medically to suppress overactive thyroids (i.e., as a hyperthyroid treatment), which raises concerns about its potential impact on overall thyroid function when consumed long-term.
If you’re looking for toothpaste alternatives that support dental health without fluoride, hydroxyapatite-based toothpaste is an excellent option. Hydroxyapatite is a naturally occurring component of teeth and bones that has been shown to strengthen enamel and promote remineralization without interfering with thyroid health.
WHY IS FLOUR BROMATED?
Bromated flour was introduced in the 1940s and 1950s as a way to improve the texture and elasticity of bread. Potassium bromate, an oxidizing agent, helps strengthen dough, allowing it to rise higher and creating a more uniform crumb structure. However, research later revealed that bromate is a known endocrine disruptor and potential carcinogen, leading to its ban in countries like Canada, the UK, and the EU. Despite this, it is still used in some baked goods in the U.S., where alternatives like ascorbic acid (vitamin C) can achieve similar results without the health risks.
WHY IS CHLORINE USED IN WATER?
Chlorination of drinking water became widespread in the early 1900s as a method to prevent waterborne diseases like cholera and typhoid. It was a major public health breakthrough, significantly reducing infection rates. However, while chlorine effectively kills harmful bacteria, its long-term impact on human health is debated. Chlorine byproducts, known as trihalomethanes (THMs), have been linked to health concerns, including thyroid dysfunction and potential carcinogenic effects. Although drinking chlorinated water may not be a major risk in small amounts, daily exposure through drinking, bathing, and cooking can add up over time.
HOW ARE HALIDES PROCESSED IN THE BODY?
Halides are primarily processed through the kidneys and liver, but their presence can interfere with thyroid hormone metabolism. The liver plays a crucial role in converting T4 (inactive thyroid hormone) into T3 (active thyroid hormone), and excess halides may disrupt this conversion by altering liver detoxification pathways. Additionally, halides can accumulate in tissues and require specific pathways—such as glutathione-based detoxification—to be efficiently excreted.
SUPPORTING YOUR THYROID IN A HALIDE-SATURATED WORLD
If you’re concerned about thyroid health and halide exposure, here are practical ways to protect and support your thyroid:
Optimize Iodine Intake—But Carefully
Seaweed, eggs, and fish are natural iodine sources.
Be mindful with iodine supplements—too much can be as problematic as too little, especially for those with autoimmune thyroid conditions like Hashimoto’s.
Reduce Halide Exposure
Use an RO filter for drinking water to remove fluoride.
Switch to unbromated flour and avoid bromated baked goods.
Install a shower filter to reduce chlorine absorption.
Support Detox Pathways
Sweat it out: Infrared saunas and exercise can help eliminate stored halides.
Eat cruciferous veggies (broccoli, cauliflower) to support liver detoxification by enhancing glutathione production, which helps bind and clear excess halides.
Support glutathione-based detoxification: through supplements like NAC, B6, selenium, vitamin C, and vitamin E; milk thistle is also wonderful liver protective herb.
Stay hydrated to flush out unwanted compounds.
FINAL THOUGHTS
While the modern world makes avoiding halides nearly impossible, awareness is the first step toward protecting thyroid health. Understanding how fluoride, bromide, and chlorine compete with iodine can help you make informed choices about diet, water filtration, and detox strategies.
Curious about your own thyroid health? Consider working with a practitioner to assess iodine levels and optimize your overall thyroid function!
