The incidence of thyroid disease has more than doubled since the early 1970s in both men and women. For women, it is the cancer with the fastest-growing number of new cases.
Many researchers are studying the possible reasons for this epidemic. While some attribute better diagnostic technology, others are studying environmental triggers affecting this vulnerable endocrine organ.
Having balanced thyroid function is an important part of achieving optimal health. The thyroid gland is important in controlling the body’s metabolism, how fast the body uses energy and makes proteins, and involved in its nervous system, calcium metabolism by producing calcitonin, and other functions. The body makes 2 primary thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine). Estimates of how many Americans are diagnosed with thyroid disorders vary depending on which organization statistics you use, between 13 and 20 million Americans.
In addition, the American Association of Clinical Endocrinologists estimates another 13 million people have undiagnosed thyroid disorders.
Women are 5x more likely than men to have hypothyroidism and 1 in 8 women will be diagnosed with this during their lifetime. A special of vulnerability to thyroid dysfunction is the post partum time when about 5% of women become either over or under active in thyroid production, and about 1/3 of these women will not rebalance.
The Endocrine Society published a study in October, 2014 documenting that Endocrine Disrupting Chemicals can interfere with thyroid activity in pregnant women. They also reviewed The EDC’s effects on other hormone sensitive tissues in their latest Scientific Statement.
Thyroid balance is also needed for normal neurological development of the brain in utero and this balance is sensitive to disruption. The first 10 weeks of conception are crucial for the fetus’ brain development and it is vital that mothers have enough thyroid hormones to share with the fetus. It has long been documented that women with low thyroid function are at higher risk of having children with lower IQ and developmental disorders.
Numerous research studies have documented interactions with environmental chemicals and thyroid hormones.
The Endocrine Society defines endocrine-disrupting chemicals as “compounds natural or synthetic, which through environmental or inappropriate developmental exposures alter the hormonal and homeostatic systems that enable the organism to communicate with and respond to its environment.” Chemicals that affect thyroid metabolism are termed “thyroid disruptors.”
The main thyroid-disrupting chemicals are the halogens family: chlorine, fluorine, bromines, and include perchlorates and polybrominated flame-retardants. In addition to thyroid disruptors, some prescription medications can also interact with optimal thyroid functioning.
Thyroid and Halogens
One of the necessary ingredients needed for thyroid production is Iodine. Several chemicals in the environment, including halogens compete with Iodine for cell receptors and can cause loss of the vital nutrient to be available to the body. Before iodine was added to salt, there were areas in the country with iodine poor soil and where the people were iodine deficient, having high incidence of swelling of the thyroid in the neck, called a goiter, thus, the “goiter belt”.
The wide spread use of chlorine to disinfect our public water exposes everyone to chlorine. Chlorine can interfere with proper thyroid conversion of the thyroid hormone T4 to T3 (the biologically active form of the hormone) and result in hypothyroidism.
Second, toxic competing halogens (chlorine, bromine, fluorine and perchlorate) have dramatically increased. These halogens inhibit thyroid hormone production. Halogens appear in our food, water, medications and environment as chlorides, bromides and fluorides and they selectively attach to your iodine receptors, preventing iodine from working. Bromine has replaced iodine as a bleaching agent in breads and baked goods. Bromine is also now used as a pesticide spray especially in strawberries, some sodas, and increasingly in pharmaceuticals. Fluoride was first added to water in the United States in the 1940s to help prevent tooth decay in children 8 years and under. Fluoride remains in most municipal drinking water supplies and is used in toothpaste in concentrations as high as 1500 parts per million. According to the EPA, safe levels should not exceed 4 parts per million.
Perchlorates inhibits iodine uptake by the thyroid, an element needed to make thyroid hormones. It’s found naturally but is primarily an industrial contaminant increasingly found in groundwater, surface water and soil. Most perchlorates are used as an ingredient in solid fuel for rockets and missiles. They can also found in non-stick cookware, safety flares, fireworks, explosives, batteries, stain resistant clothing and automobile restraint systems.
More alarmingly, perchlorates have contaminated most of the lettuce in the US, non-stick cookware, microwave popcorn bags, fruits, vegetables and grains irrigated by perchlorate-contaminated water, and milk products from cows grazing on contaminated grasses.
According to the CDC, even small amounts of exposure can have physiological effects, at levels as low as 3 parts per billion. They estimate that a person’s average daily exposure is 5 parts/billion. The CDC claims that levels higher than this are still “safe”, although Massachusetts set their standard at 2 parts per billion in July of 2006. An ingredient in cigarette smoke, called thiocyanates can have effects similar to potassium perchlorate.
According to the NRDC: (National Resource Defense Council)
Although PCB’s (polychlorinated biphenyls) have been banned since the 1970’s they still linger in our environment and appear in Body Burden Chemical testing. The effects are similar to the perchlorates on the womb on the developing fetus and in infants and children during growth and developmental periods.
Triclosan, an antibacterial chemical added to soaps, toothpastes, bath towels and many other products, interferes with thyroid hormones in North American bullfrogs, leading to limb deformities, according to a study published in the December 2006 issue of Aquatic Toxicology. When it comes to the thyroid system, the similarities between humans and amphibians are enough to give scientists cause for concern.
Plastic-softening phthalates have been found to reduce thyroid hormone levels in men. These chemicals are commonly found not only in plastics but also in consumer products (whose labels may list them as “fragrance”). Because they are so broadly used, phthalates may affect a large number of people.
PBDEs, widely used flame-retardants (polybrominated diphenyl ethers), have been found in several studies to disturb thyroid function. They are commonly used in furniture, bedding, clothing, and are widely detected in house dust and found in the bodies of most people in this country. They are linked to behavioral and developmental problems.
BPA (bisphenol A) is found in plastics and the liners of food cans including baby formula, and dental sealants. BPA can alter the function of thyroid hormone in the brain, potentially leading to the development of attention deficit hyperactivity disorder.
What you can do:
• Avoid toxic substances in cookware, plastics, body care products
• Wash fruits and vegetables ad eat organically when possible.
• Reduce flame retardant exposure when buying new items
• If you are pregnant, be screened for thyroid disorders as soon as possible.
• Tell your obstetrician if there is a family history of thyroid disorders or autoimmune disorders such as juvenile (type 1) diabetes, rheumatoid arthritis, pernicious anemia due to a lack of vitamin B12, or colitis.
• Check your neck: watch for any swelling or painfulness in the thyroid area.
• Most Americans consume enough iodine in their diet, but if you don’t use iodized salt or eat fish, you may not be getting enough. Talk to your doctor about your iodine intake.
• Have your water tested if you suspect contamination from perchlorate, pesticides or herbicides. This is especially important if you drink well water.
For further information:
http://www.ncbi.nlm.nih.gov/pubmed/15132715. The environment and autoimmune thyroid diseases. Prummel MF, Strieder T, Wiersinga WM.
Association between Serum Perfluorooctanoic Acid (PFOA) and Thyroid Disease in the U.S. National Health and Nutrition Examination Survey Environ David Melzer,1 Neil Rice, Michael H. Depledge, William E. Henley,et al
http://www.ncbi.nlm.nih.gov/pubmed/16451540 Davies RM, Ellwoo, RP, Davies GM. The rational use of fluoride toothpaste
Long term exposure to organochlorine pesticides and thyroid function in children from Cidade dos Meninos, Rio de Janeiro, Brazil.
Bromine and thyroid hormone activity.
P Allain, S Berre, N Krari, P Laine, N Barbot, V Rohmer, and J C Bigorgne
ATSDR – Polychlorinated Biphenyls (PCBs)
Leonidas H. Duntas and Nikos Stathatos Journal: Reviews in Endocrine and Metabolic Disorders, 2016