Study Finds Link Between Chemicals in Plastics and Thyroid Levels

From the Examiner (MI).

"A study at the University of Michigan describes a link between chemicals found in common plastics and solvents and thyroid levels.

Scientists studied urine and serum thyroid data of 1,346 adults and 349 children from the National Health and Nutrition Examination Survey. They found that large concentrations of phthalates and BPA in urine resulted in lowered serum thyroid levels.

Researchers found that the most significant decrease in levels (up to 10%) occurred with individuals that were in the highest 20% of exposure to DHEP compared to the lowest 20%. DHEP is a plasticizer that is commonly found in polyvinyl-chloride-based products. These products are widely used in hospitals, such as cardiac catheters, endotracheal tubes, and dialysis and blood bags.

This seems like a subtle difference," John Meeker, assistant professor at the U of M SPH, and lead study author said, "but if you think about the entire population being exposed at this level you'd see many more thyroid-related effects in people."

The thyroid is extremely important in the human body. It helps maintain the proper energy levels your body needs to function efficiently. A decrease in thyroid levels could result in fatigue, weight gain, and slower heart rates.

Although the study does suggest a link between these chemicals and serum thyroid levels, further study is essential. No cause-and-effect connection has been made. In other words, the results do not explicitly state that phthalates and BPA cause the low thyroid levels.

Also, since DHEP is more common in a hospital-setting, more studies should focus on evaluating blood and serum levels of individuals that have not stayed in a hospital or had a medical procedure performed recently.

Still phthalates and BPA, in particular, has been extensively studied. Concerns over the safety and efficacy of it in canned foods and soft drinks and other food packaging have led to bans from European Union and Canada. It has not been federally banned in the U.S., though Maine has decided to prohibit the manufacturing, distribution, and selling of this substance.

Meeker also points out that more studies are needed that will study pregnant and young children. If a causal relationship does exist, the latter demographic may be extremely vulnerable to the effects of low thyroid levels.

The study is presented in the journal, Environmental Health Perspectives."

Products to Avoid
If you want to avoid products with BPA, keep in mind the following:

Plastic that contains BPA carries the #7 recycling symbol.
Most clear plastic baby bottles and child cups are made of BPA-containing plastic.
Dental sealant may leach BPA; this is being debated. You may want to avoid dental sealants on your children's baby teeth.

Minimize your BPA exposure by:

Replacing plastic food and drink containers and utensils with glass, ceramic or metal varieties.
Purchasing glass baby bottles.
Using baby bottles and sippy cups made of polyethylene plastic (#1, #2, #4 recycling symbols) or polypropylene (#5) (these are usually colored, not clear, and should still not be heated).
Not using canned foods or foods wrapped in plastic.
Not letting children put plastic toys in their mouths.
Being careful with BPA-containing plastics, if you choose to use them. This means not exposing them to heat (microwave, dishwasher) or harsh detergents (bleach, etc.) and not letting food or beverages sit in the containers for too long.

For food storage containers, Ziplock makes the safest microwavable containers and zippy bags that are all BPA-free. If you must buy stuff in cans, Eden brand (available in health food stores) is a company that uses BPA-free can liners.