Avoiding all toxic chemicals is obviously important, but this is often easier said than done. These days we are surrounded by harmful substances, including heavy metals and other toxic industrial pollutants, chemicals in everything from household cleansers to fabrics to body care items, and even seemingly benign food additives.
Exposure to heavy metals causes a complex cascade of effects in our bodies, including activating the immune system. This can lead to problems with hypothalamus, pituitary, thyroid, and adrenal functions. The metals that most commonly cause immune reactivity are nickel, mercury, chromium, cobalt, and palladium.
The U.S. Centers for Disease Control ranks toxic metals as the number one environmental health threat to children, with mercury, lead, arsenic, and cadmium all ranked in the top eight most toxic; chromium is also high on the list (Agency for Toxic Substances and Disease Registry 1999). These toxic metals can cause fatigue, pain, sleep disturbances, severe psychological symptoms such as depression, and gastrointestinal and neurological problems.
It’s been well-known for years that mercury disrupts the endocrine system and can result in severe damage to both this system and the nervous system. Studies have shown that mercury causes hypothyroidism, autoimmune thyroiditis, and damage to thyroid RNA, and also impairs conversion of T4 to T3 (Sterzl et al. 2006). It blocks thyroid hormone production by interfering with iodine utilization and prevents normal action of thyroid hormones. This results in inadequate thyroid stimulation even though your thyroid hormone levels may appear to be normal. Mercury also blocks your body’s ability to effectively use vitamins B6 and B12, calcium, magnesium, and zinc, which are all important to thyroid function.
Mercury rapidly crosses the blood-brain barrier and is stored first in the hypothalamus, pituitary, and occipital lobe (responsible for visual processing). It damages these areas, as well as the blood-brain barrier itself, enabling other toxic metals and substances to penetrate the brain. It’s also stored in, and damages, the thyroid. The hormones most often affected by mercury are thyroid hormones, insulin, estrogen, testosterone, and adrenaline. Major sources of mercury exposure are mercury amalgam dental fillings and thimerosal, a mercury-based preservative found in vaccinations and other medicines.
Lead can also be toxic to your thyroid gland and in clinical studies has been shown to raise TSH levels and lower T3 (Singh et al. 2000). Lead has widely known adverse effects on the nervous system. It can also damage the endocrine system and may seriously affect reproductive function, as well as organs and tissues.
We’re exposed to cadmium, an industrial pollutant, from a wide variety of sources. It’s found in auto exhaust, industrial waste, cigarette smoke, sewage sludge, batteries, and fertilizers. Both drinking water and food crops may also be contaminated with cadmium. High levels of cadmium can cause not only thyroid abnormalities but also kidney and liver damage and anemia.
If you have symptoms of hypothyroidism, it’s important to ask your doctor to measure your levels of toxic metals, as they can damage your thyroid gland, your entire endocrine system, and your nervous system. The best way to do this is with something known as a urine challenge test. For this test, you take a pill containing a substance that has an affinity for binding to heavy metals. This causes them to be excreted in your urine, where their levels can be measured. If they’re elevated, you should work with your doctor to reduce levels of toxic heavy metals in your body.
Toxic chemicals and pollutants enter our bodies all the time, and we continually eliminate them naturally through the kidneys and colon. But many toxins are able to imitate our natural biochemicals (including hormones) and get into our cell walls. The toxins that mimic our hormones fit into hormone receptor sites on cell surfaces and hamper the body’s ability to eliminate them. This also blocks hormones from binding with those sites and performing their normal functions and leads to cell and tissue damage.
Iodine falls into the class of elements known as halogens, which also includes fluorine, chlorine, and bromine (and the obscure astatine). Because these elements share certain characteristics, they react similarly. As a result, fluorine, chlorine, and bromine can bind with iodine receptors in the thyroid gland, which results in decreased production of thyroid hormones. Unfortunately, we’re awash in a sea of halogens and compounds that contain them: fluorine in tap water and toothpastes (in the form of fluoride); chlorine in tap water, sanitizers, cleansers, and plastics; and bromine in some bread products, brominated vegetable oil (an emulsifier added to certain soft drinks), hot tub cleansers, plastics, personal care products, certain medications, fabric dyes, and fire retardants. Fluorine, chlorine, and bromine have also been implicated in other thyroid diseases, not just hypothyroidism. This includes autoimmune diseases and even thyroid cancer (Malenchenko, Demidchik, and Tadeush 1984). In adequate amounts, iodine will push out excessive fluorine, chlorine, and bromine from your body, making it an excellent natural detoxifier.
Food additives are an often-overlooked cause of toxic chemical exposure. Your thyroid is continually being assaulted by chemicals and hydrogenated oils (trans fats). The process of hydrogenation alters the chemical makeup of fats to give them an extended shelf life. However, this alteration also causes them to disrupt the normal functioning of cells and blocks our utilization of fatty acids, which are critical in thyroid function. Trans fats have been implicated in various other health problems, too, especially heart disease. Fortunately, regulatory agencies and food manufacturers are starting to take notice, so the use of trans fats is beginning to decrease. Some states are getting serious about it. New York has led the way as the first state to ban their use in all restaurants. In the meanwhile, read labels carefully and be aware that these damaging fats are often used in bakery products and fast-food restaurants, where they’re used for deep-frying.
Reprinted with permission: New Harbinger Publications, Inc. Copyright © 2009 by Kathryn R. Simpson, MS
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