You may be getting more than you expect when you open a packaged food container or plastic drink bottle, just ask your thyroid. Chemicals from the packaging, which you won’t find listed in the ingredients, can leak into the contents before you consume them. Hidden additives may include chemicals called phthalates and BPA. A study conducted at the University of Michigan suggests that some of these chemicals may affect levels of your thyroid hormones.
So what does that mean to you? Your thyroid gland is a key regulator of essential body processes. The hormones it releases affect your energy level and the functioning of your nervous, reproductive, cardiovascular, and pulmonary systems. That’s a lot of systems; it’s easy to see why anything that might affect thyroid function would attract the attention of public health scientists.
The University of Michigan-based scientists found that increased urine levels of certain chemical by-products were associated with decreased blood levels of some important thyroid hormones. This association was greatest for DEHP, a phthalate that usually enters the body in food. It and other phthalates are found in plasticizers (such as in shower curtains), solvents and everyday items found in the home. People with the highest levels of DEHP had as much as a 10 percent decrease in thyroid hormones levels.
Although this study, with 1,346 adult and 329 adolescent participants, was larger than previous studies, it wasn’t able to establish a direct link between exposure to phthalates and thyroid hormones levels. The researchers obtained blood and urine samples only at one time point. A future study with multiple samples collected over time could establish a cause-and-effect relationship between exposure to unwanted additives and hormone levels.
The conclusion for safety-conscious consumers is to limit consumption of processed, packaged foods and step up consumption of fresh foods.