Halogens, Halogenated Chemicals, and Thyroid Health
Written by Ryah Nabielski, MS, RDN
I’m endlessly curious about how the environment affects our health and hormones. We are exposed to toxic chemicals in our water, food, air, and even materials and products in our homes. Many of these chemicals are invisible sources of hormone disruption.
If you have symptoms of low thyroid function (fatigue, cold intolerance, weight gain), have been diagnosed with a thyroid condition, or want to prevent thyroid issues, today’s article is for you.
Halogens and halogenated chemicals might be disrupting your thyroid health. Keep reading to learn more about:
· What are halogens, and where are they found?
· How halogens impact thyroid function
· What you can do to reduce your exposure to unwanted halogens in your environment
Let’s get started!
What Are Halogens?
Halogens are a group of elements that share similar properties. You’ll find halogens on the periodic table in the second column from the right. Halogens include:
· Fluorine
· Chlorine
· Bromine
· Iodine
They are all naturally occurring elements, but only one is essential to human health: iodine. We may be exposed to others in trace amounts through contact with the natural world (like rocks and soil). But we are increasingly exposed to higher levels of fluorine, chlorine, and bromine through human activity and industrial chemicals.
The Importance of Iodine
Iodine is a mineral building block for thyroid hormones thyroxine (T4) and triiodothyronine (T3). T4 contains four molecules of iodine, and T3, your active thyroid hormone, contains three molecules of iodine.
Seventy to 80% of the iodine in the body is concentrated in the thyroid gland for thyroid hormone production. The rest is found in breast tissue and throughout the body. [1]
When we don’t have enough iodine in the body, it affects thyroid hormone production and breast health. Deficiencies in other micronutrients involved in thyroid metabolism, namely selenium, iron, and vitamin A, can make an iodine deficiency more severe. [1]
Iodine is a critical nutrient during pregnancy and breastfeeding; baseline daily needs increase during this time. Iodine deficiency can lead to irreversible problems with fetal and infant brain development. [1]
In addition to pregnant and lactating women, vegetarians/vegans, infants, and children are at risk for deficiency because they might not get enough iodine in their diet. [1]
Halogens and Thyroid Function
While iodine is necessary and critical for thyroid health, other halogens disrupt thyroid function. Because all halogens have similar properties, when halogens (fluorine, chlorine, bromine) and chemicals containing them enter the body, they concentrate in the thyroid gland and displace the iodine required for thyroid hormone production.
From this perspective, halogens and halogenated chemicals are endocrine disruptors; they disrupt normal hormone function. And every cell in the body depends upon thyroid hormones for metabolic function, so the physical effects can be widespread.
Signs, symptoms, and conditions that may be related to suboptimal thyroid hormone levels include:
· Weight gain or weight loss resistance
· Slow digestion, constipation, acid reflux
· Hair loss
· Cold intolerance, cold hands and feet
· Fatigue, sluggishness
· Fibrocystic breasts
· Fertility challenges, miscarriage
· Imbalances in sex hormones, changes in the menstrual cycle
· Hypothyroidism (clinically low thyroid hormone)
· Hashimoto’s thyroiditis (autoimmune hypothyroidism)
· Subclinical hypothyroidism or low T3 syndrome (signs and symptoms of low thyroid hormone, but labs may still be within range)
Toxic Halogens and Halogenated Chemicals
Halogens and halogenated chemicals displace iodine, impacting thyroid hormone production and body-wide metabolic health. In addition, these chemicals are directly toxic to the body, impacting tissue and organ systems, detoxification pathways, and the immune system.
Let’s take a closer look at fluorine and fluorinated chemicals, chlorine and chlorinated chemicals, and bromine and brominated chemicals.
Fluorine
Fluorine is a naturally occurring element found in the earth’s crust, but we are exposed to greater levels via:
· Fluoride toothpaste
· Fluoridated water
· Fluorinated chemicals like PFAS
Fluoride pros and cons: There is no doubt that fluoride toothpaste reduces cavities with topical use when fluoride contacts the teeth. Fluoride has been added to municipal water in the United States since 1945 with the same goal of preventing cavities. However, systemic fluoride exposure carries health risks, including brain toxicity.
Current literature reviews state that fluoride exposure has the potential for significant adverse health effects and that the risk of fluoride is not worth the reward of reducing cavities. [2] In other words, teeth are easier to fix than the brain.
Fluorine is a component of fluorinated industrial chemicals like PFAS (per- and polyFLUOROalkyl substances). Known as “forever chemicals” because they don’t break down, PFAS are found in:
· Tap and bottled water
· Food packaging
· Waterproof or water-resistant apparel and gear
· Carpets and upholstery
· Cleaning products
· Makeup (waterproof mascara, for example)
· Non-stick coatings (Teflon cookware, for example)
· Sports bras and period panties [3, 4]
PFAS contaminate the air, water, and soil around the globe. We are exposed through drinking water, food, and skin contact. Just about every one of us has detectable PFAS in our blood. [3]
The health consequences of PFAS are widespread. Exposures correlate with:
· Negative impact on fertility [5]
· Weight gain and reduced metabolic rate [6]
· Increased risk of type 2 diabetes [7]
· Alterations of thyroid function and reduced levels of T4 [8]
Chlorine
Chlorine and chlorinated chemicals are added to municipal water, swimming pools, and cleaning supplies as disinfectants, designed to keep us safe by killing pathogens. Toxic byproducts of chlorinated chemicals are formed when they contact other molecules. [9]
We are exposed to these chemicals and their toxic byproducts by
· Drinking chlorinated tap water
· Drinking shower water or pool water
· Transdermal absorption (through the skin) when bathing, swimming, or cleaning
· Breathing in chlorinated chemicals in a hot shower or fumes from cleaning products
While the chlorination of municipal water has benefits, it doesn’t necessarily ensure the safety of drinking water as organisms may become resistant to disinfectants (similar to antibiotic resistance). [10]
Chlorine and other disinfectants don’t just kill bacteria and microorganisms in water, they can kill or alter beneficial organisms in the gut. New research suggests that the source of drinking water has a profound impact on the microbiome and therefore, overall health. [11]
Bromine
Bromine is another naturally occurring element in the earth’s crust, which is highly toxic in manufactured products.
Bromine and chemicals containing bromine ions or bromine salts include:
· Flame retardants (PBDE - polyBROMINATED diphenyl ethers)
· Agricultural and aerosol chemicals – although there are efforts to move away from methyl bromide, it is still applied to non-organic strawberries and some other crops
· Sanitation chemicals - alternative to chlorine used in swimming pools
· Potassium bromate - used in ultra-processed bread and flour products
· Brominated vegetable oils – found in soda and other ultra-processed items [12, 13]
Humans are exposed to bromine via food, water, air, and skin contact. An acute high-level exposure (bromine poisoning) is immediately toxic to organs. One study found pregnant women living near agricultural methyl bromine use displayed markers of fetal growth restriction. [12, 14]
However, most of us are exposed to lower levels over a lifetime, which may equate to thyroid or other issues. In addition, there isn’t much data on low-level exposure to hundreds or thousands of chemicals simultaneously. Because of unknown cumulative effects, it makes sense to avoid the toxins that we can.
How To Naturally Increase T3 and Improve Thyroid Health
Here are some tips for avoiding toxic halogens and halogenated chemicals to improve thyroid function:
1. Eat organic, whole foods. Choose unprocessed, organic options as much as possible to avoid exposure to pesticides and additives. Read ingredient lists for every product you buy. While there are many ingredients to avoid in processed food, avoid products containing bromine, bromide, or brominated on the label. Assume that all products containing bromide are toxic. Be sure to choose organic strawberries.
2. Filter your water. The best water for hypothyroidism is filtered water. Choose a quality water filter that removes chlorine and fluoride from drinking water. I personally use a ProOne countertop filter (no affiliation).
Consider filtering your bath/shower water to remove chlorine. You can get a filter to attach to your shower head or utilize a whole-house filter. A simple way to reduce chlorine in bath water is by adding ¼ teaspoon of vitamin C powder to a full bath.
3. Rethink your toothpaste. Because of the connection between changes in the thyroid and fluoride, consider using an alternative toothpaste.
Unfortunately, most natural toothpaste doesn’t contain an active ingredient that works to mineralize teeth. Luckily, hydroxyapatite toothpaste is a safe and effective option. Hydroxyapatite is the natural matrix of your teeth that works to fill in deposits, prevent cavities, and whiten teeth. It’s a wonderful, fluoride-free option with a long history of successful use, especially in Japan. [15]
Boka and RiseWell are brands I like and use (no affiliation).
4. Incorporate iodine-rich foods into the diet. Just as halogens displace iodine, having enough iodine crowds out any halogens that make their way to your thyroid.
Ensure you are meeting your daily iodine needs by including seaweed and seafood in the diet. Other whole food sources include eggs, grass-fed dairy, and beans. Iodized sea salt is quite processed and often contains anti-caking agents or contamination. I prefer using quality sea salt and incorporating seaweed into my diet.
(When you sign up for my email list below, you’ll get my hormone guide which includes a green salt recipe, a delicious way to add iodine and other to seasoning salt).
An important caveat about seaweed, iodized salt, and iodine supplements is for those with thyroid disease. It’s important to have enough iodine, but too much can be detrimental for some people. If you have a thyroid condition, work with your healthcare provider or nutritionist to determine the best solution for you.
Halogens and halogenated chemicals are just one of many interactions between the environment and women’s health. When we understand the connection, we can make small shifts in our lifestyle to help limit toxin exposures and optimize our health and hormones.
The contents of this post and website are for informational purposes only and are not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions regarding a medical condition.
References
1. Linus Pauling Institute Micronutrient Information Center. Iodine. Accessed 10.27.22.
2. Peckham, S., & Awofeso, N. (2014). Water fluoridation: a critical review of the physiological effects of ingested fluoride as a public health intervention. TheScientificWorldJournal, 2014, 293019.
3. Starnes, H. M., Rock, K. D., Jackson, T. W., & Belcher, S. M. (2022). A Critical Review and Meta-Analysis of Impacts of Per- and Polyfluorinated Substances on the Brain and Behavior. Frontiers in toxicology, 4, 881584.
5. Bach, C. C., Vested, A., Jørgensen, K. T., Bonde, J. P., Henriksen, T. B., & Toft, G. (2016). Perfluoroalkyl and polyfluoroalkyl substances and measures of human fertility: a systematic review. Critical reviews in toxicology, 46(9), 735–755.
6. Liu, G., Dhana, K., Furtado, J. D., Rood, J., Zong, G., Liang, L., Qi, L., Bray, G. A., DeJonge, L., Coull, B., Grandjean, P., & Sun, Q. (2018). Perfluoroalkyl substances and changes in body weight and resting metabolic rate in response to weight-loss diets: A prospective study. PLoS medicine, 15(2), e1002502.
7. Sun, Q., Zong, G., Valvi, D., Nielsen, F., Coull, B., & Grandjean, P. (2018). Plasma Concentrations of Perfluoroalkyl Substances and Risk of Type 2 Diabetes: A Prospective Investigation among U.S. Women. Environmental health perspectives, 126(3), 037001.
8. Kim, M. J., Moon, S., Oh, B. C., Jung, D., Ji, K., Choi, K., & Park, Y. J. (2018). Association between perfluoroalkyl substances exposure and thyroid function in adults: A meta-analysis. PloS one, 13(5), e0197244.
9. Srivastav, A. L., Patel, N., & Chaudhary, V. K. (2020). Disinfection by-products in drinking water: Occurrence, toxicity and abatement. Environmental pollution (Barking, Essex : 1987), 267, 115474.
10. Fish, K. E., Reeves-McLaren, N., Husband, S., & Boxall, J. (2020). Unchartered waters: the unintended impacts of residual chlorine on water quality and biofilms. NPJ biofilms and microbiomes, 6(1), 34.
11. Vanhaecke, T., Bretin, O., Poirel, M., & Tap, J. (2022). Drinking Water Source and Intake Are Associated with Distinct Gut Microbiota Signatures in US and UK Populations. The Journal of nutrition, 152(1), 171–182.
12. https://emergency.cdc.gov/agent/bromine/basics/facts.asp
13. Holmes, G. J., Mansouripour, S. M., & Hewavitharana, S. S. (2020). Strawberries at the Crossroads: Management of Soilborne Diseases in California Without Methyl Bromide. Phytopathology, 110(5), 956–968.
14. Gemmill, A., Gunier, R. B., Bradman, A., Eskenazi, B., & Harley, K. G. (2013). Residential proximity to methyl bromide use and birth outcomes in an agricultural population in California. Environmental health perspectives, 121(6), 737–743.
15. Bossù, M., Saccucci, M., Salucci, A., Di Giorgio, G., Bruni, E., Uccelletti, D., Sarto, M. S., Familiari, G., Relucenti, M., & Polimeni, A. (2019). Enamel remineralization and repair results of Biomimetic Hydroxyapatite toothpaste on deciduous teeth: an effective option to fluoride toothpaste. Journal of nanobiotechnology, 17(1), 17.