It’s not news that pollutants in our air could be making many of us sick — but it is news that a particular chemical could be causing thyroid problems in women.
A recent Centers for Disease Control and Prevention (CDC) study has confirmed the suspected link between “perchlorate” and thyroid health. Perchlorate is a chemical that occurs naturally and is also manufactured by humans for use in rocket fuel, fireworks, road flares, and other industrial applications.
According to the U.S. Food and Drug Administration (FDA), this chemical can be found in our soil and water, which means that the water we’re drinking and the food we’re eating are potential health hazards. For example, milk, drinking water, spring water, and lettuce have all been found to contain perchlorate.
The FDA and other government agencies are still attempting to determine if these sources of the chemical are harmful to people (and it’s studies like this that suggest they are) and, if so, how we can screen for and eliminate the chemical.
The thyroid gland, as part of the endocrine system in the body, secretes hormones (mainly thyroxine and triiodothyronine) that control many important bodily functions, including metabolism. Iodine is a natural chemical that is essential for thyroid hormone production. Thyroid stimulating hormone (TSH), which comes from the anterior pituitary gland, regulates the production of thyroxine (T4).
There are two primary thyroid diseases: hypothyroidism (underactive thyroid, meaning not enough hormones are produced) and hyperthyroidism (overactive thyroid). There can be many symptoms of these conditions, as the thyroid hormones control the production and distribution of energy in the body. Some signs of hypothyroidism are memory problems, lack of overall energy, dry skin, weight gain, difficulty swallowing, depression, and pale skin.
The CDC study looked at 2,299 men and women, who were over the age of 12. The data was taken from the 2001/2002 National Health and Nutrition Examination Survey. Researchers examined levels of perchlorate in the urine of the subjects and compared these to how much TSH and total T4 was in the blood.
The interesting part of the results was that perchlorate did not have a meaningful relationship with TSH and T4 levels in men. However, in women, it was another story. For women with lower iodine levels in their blood, the amount of perchlorate found in their urine was consistent with reduced levels of the thyroid hormones. For women with higher iodine levels, urinary perchlorate seemed to be related to lower levels of TSH only (not T4).
When present in large amounts in the body, perchlorate can tamper with the function of the thyroid by blocking the absorption of iodide (a vital compound in iodine). This is what could lead to hypothyroidism or even thyroid gland tumors. However, more population-based studies are needed to verify the link between perchlorate and actual thyroid conditions (and not just thyroid hormone levels).