The Chemicals That Can Affect Your Metabolism

The Chemicals That Can Affect Your Metabolism
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Chemical exposures can have a significant effect on your metabolism by reducing thyroid hormone levels or impairing thyroid hormone action.

Your thyroid is responsible for maintaining healthy metabolism and growth, so when it slows down (hypothyroidism) you can experience constipation, weight gain and/or loss of hair as well as fatigue and sensitivity to the cold. Initially you may not notice any symptoms, and you may think you are overworked and exhausted or just getting old, but as your metabolism slows even further you will start feeling the symptoms of hypothyroidism.

According to the Thyroid Journal, approximately 70 percent of Hashimoto's (autoimmune thyroid disease) is due to genetics; the remaining 20-30 percent are due to environmental exposures and triggers.

Some of the thyroid disruptors lurk in the bread you get from the supermarket, your cosmetics and your beloved strawberries. Let's look at what kind of environmental toxins you are likely to be exposed to, and that in accumulated amounts can cause a thyroid disease:


Halogens (bromines, fluorine and chloride) compete for the same receptors as iodine. Fluorine and chlorine are found in the water supply and bromines are found in flame-retardants, soft drinks, commercial breads and pesticides. Bromines are found in most strawberries in Australia, despite the particular pesticide being banned around the world.


Perchlorate is both a naturally occurring and man-made chemical used in the production of rocket fuel, missiles, fireworks, flares and explosives. It can also be present in bleach and in some fertilizers.

Perchlorate in the environment is a health concern because it can disrupt the thyroid's ability to produce hormones and is considered a likely carcinogen by the U.S. Environmental Protection Agency (EPA). Unfortunately, Perchlorate is now found to be present in most people's blood.


PCBs are used as pesticides and combustion processes, and although, they have been banned for a long time they are still to be found in our food supply. PBDEs are found in flame-retardants, plastics, paints, electronic equipment and synthetic textiles. Both PCBs and PBDEs have been shown to have a negative effect on the thyroid in that they reduce the thyroid hormones.

BPA and phthalates

BPA and phthalates are endocrine disruptors. BPA is found in many plastics such as water bottles, food containers and the lining of canned goods, and phthalates are found in cosmetics, shampoo, laundry detergents, water and some dairy products.

UV filters

UV filters found in sunscreens and other cosmetic products have shown to decrease the circulation of thyroid hormones in rats but no human studies have been done.

Other environmental factors that increase the risk of thyroid disease include, radiation exposure, both from nuclear fallout and medical radiation, cigarette smoke (big one), nitrates found in water and processed meats.

Medication and hypothyroidism

Some medications can contribute to hypothyroidism such as beta-blockers, theophylline, amiodarone, Phenytonin, Lithium and chemotherapy

Heavy metals

Mercury toxicity affect the peripheral conversion of T4 to T3. If you eat a lot of tuna or in any way think you may have been exposed to any heavy metals, you can have a hair analysis or a urine test done to test your levels.

In summary:

Buy organic where possible and avoid cleaning with chemicals, use natural cleaning products instead. Buy toxin free cosmetics and shampoo and use a natural laundry detergent.

Ventilate your car when driving to get all the plastic fumes out, especially if it's a new car -- windows down, arm out the window and loud 90s hip hop music, you get the picture? If you are renovating look into toxin free paints, floors and carpets.

The BPA found in the lining of many cans gives you another reason to never drink soft drinks, would you like som BPA with that? Also check that your tomato and coconut milk cans are BPA free. Get a stainless steal or a glass bottle for drinking on the go.

Finally, filter your tap water. You can get a reverse osmosis system to go under the sink that takes all the nasties out and replaces it with the alkalising minerals.

Pernille Jensen is a naturopath and the founder of Rewired Living. Join her newsletter at

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