Our environment is just as important as the food we eat to maintain optimal thyroid health. The thyroid is very susceptible to damage from environmental toxins. Several environmental toxins contain substances that mimic the thyroid structure and invade the thyroid gland. This disruption can negatively impact thyroid hormone production, thyroid hormone conversion, and overall thyroid health. Regular exposure to these toxins increases the risk of thyroid gland damage and dysfunction. It is important to learn where these toxins are found so you can do your best to avoid them.
How environmental toxins impact thyroid health
The thyroid is very susceptible to damage from influences outside of the body, such as environmental toxins. The structure of thyroid hormones increases the thyroid’s susceptibility to damage. Several environmental toxins contain substances (i.e., bromine, chlorine, fluorine) that can mimic thyroid hormone structure, displace iodine (an essential building block), and invade the thyroid gland.
The 4 main groups of environmental toxins & how they can affect the thyroid
1. Heavy Metals
- Aluminum
- Induces oxidative stress on the thyroid gland.
- Inhibits iodide uptake.
- Limits thyroid hormone production.
- Can mislead the immune system to attack the thyroid.
- Cadmium
- Triggers thyroid enlargement.
- Produces multinodular goiters of the thyroid.
- Reduces thyroglobulin secretion.
- Can induce thyroid cancer.
- Present in batteries, pigments, plastics, sewage, & phosphate-based fertilizers.
- Lead
- Linked to reduced thyroid function & increased levels TSH.
- Found in paint used in old housing, some metal jewelry, some children’s toys, mining, and other forms of industrialization.
- Mercury
- Lowers iodide uptake in the thyroid.
- Prevents thyroid hormone production.
- Found in seafood, dental amalgams, and pollution produced by coal-burning power plants.
2. Household Products
- BPA & Phthalates
- Mimics the structure of thyroid hormones.
- Changes the structure of the thyroid gland and inhibits T3 from binding to hormone receptors.
- Found in plastic food and beverage containers, the lining of some canned foods, some children’s toys, and cash register receipts.
- Triclosan
- Antibacterial chemical found in products such as liquid hand soap, body wash, toothpaste, cosmetics, and personal care products.
- Decreases T4 production.
- Polybrominated Diphenyl ethers (PBDEs)
- A flame retardant found in computer and TV screens, furniture, carpet padding, and synthetic textiles.
- Imitate thyroid hormone structure & bind to T4 receptors, blocking T4 transport in the blood.
3. Agricultural Agents
- Pesticides, Herbicides, & Fungicides
- Alter thyroid hormone gene expression.
- Prevent the uptake of iodine into the thyroid.
- Block thyroid hormone from binding to its transport proteins.
- Lower the absorption of thyroid hormone into thyroid cells.
- Promote thyroid hormone removal from the body.
- Exposure to organochlorine pesticides, the herbicide paraquat, and the fungicides benomyl and maneb/mancozeb has been associated with an increased incidence of hypothyroidism in women.
- Exposure to organophosphates & carbamates has been associated with hypothyroidism in men.
4. Industrial Chemicals
- Perchlorate
- Competes with iodide, a building block of T4, for uptake by the thyroid gland resulting in reduced thyroid hormone production.
- Found in rocket fuel, explosives and used in manufacturing leather, rubber, paint, and batteries. Water and soil can become polluted with percolate. Drinking water, grains, produce, and dairy products from animals raised on contaminated soil may contain elevated levels of perchlorate.
- Perfluorinated Chemicals (PFCs)
- Either increase thyroid hormone production to dangerously high levels (more common in women) or decrease thyroid hormone production to dangerously low levels (more common in men).
- Used to make coatings & products that resist heat, oil, stains, grease, and water. It is often found in nonstick cookware, stain and/or water-resistant carpet, clothing, and furniture.
- Polychlorinated Biphenyls (PCBs)
- Suppresses the production of the thyroid hormone receptor, reducing the number of receptors available for T3 to bind to.
- Decreases the amount of T4 circulating in the bloodstream.
- Prevents liver enzymes from converting T4 into T3.
- Have been found to raise thyroid antibody levels and promote enlargement of the thyroid gland.
- Widely used as lubricants, in electrical equipment, and for adhesive, paint, or plastic production.
- Dioxin
- Mimics thyroid hormone structure and binds to cell receptors that enhance hormone excretion.
- Linked with decreased T4 and reduced thyroid function.
- Byproduct of manufacturing processes, including pesticide and plastic production.
Tips to reduce toxin exposure
While it is impossible to avoid toxins completely, focus on swaps you can make in your home and personal environment to help lower your overall toxic burden. Every small change can add up to make a significant impact and protect your thyroid.
- Avoid BPA
- Use glass, ceramic, and silicone containers for food storage and drinking.
- Avoid cash register receipts when possible.
- Choose “BPA-Free” canned foods, fresh foods, or foods packaged in glass.
- NOTE: “BPA-free” plastic may still contain endocrine-disrupting properties.
- Avoid heating plastic containers in the microwave and dishwasher.
- Purchase Safer Cleaning & Beauty Products
- Avoid personal care products with “triclosan” on the label & products labeled “antimicrobial.”
- Switch to toiletries & beauty products free of heavy metals.
- Avoid PFCs
- Replace non-stick cookware with cast iron or stainless steel options.
- Avoid stain/water-resistant coatings on carpets, clothing, & furniture.
- Invest in a High-Quality Water Filter
- A reverse osmosis water filter can help to reduce perchlorate in drinking water.
- Stop Using Pesticides/Herbicides
- Avoid using pesticides, herbicides, and fungicides (or fertilizers that contain them) in the yard and garden.
- Buy Organic When Possible
- At the minimum, focus on purchasing organic varieties of “The Dirty Dozen.” The Dirty Dozen is a list of fruits and vegetables with the highest level of pesticide residues created by the Environmental Working Group (EWG).
- Dirty Dozen: Strawberries, spinach, kale/collard/mustard greens, nectarines, apples, grapes, bell/hot peppers, cherries, peaches, pears, celery, & tomatoes.
We hope you enjoyed this blog post, “Protect Your Thyroid by Avoiding These Environmental Toxins.” What do you plan to start removing from your home?
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