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While it's not clear yet just how these chemicals screw with your D levels, there are a few theories, says study coauthor John Meeker, ScD, a professor of environmental health sciences at Michigan.
Both BPA and phthalates may disrupt digestive and metabolic enzymes that help convert vitamin D into something your body can use, Meeker says. It's also possible these chemicals throw off your body's balance of calcium, which in turn limits the activity of vitamin D in your system. But more research is needed to sort out all the cause-and-effect details—including why these chemicals may harm women's D levels more than men's, Meeker adds.
Phthalates and BPA have both made the news lately, and for all the wrong reasons. Both chemicals are endocrine disruptors, meaning they can mess with the way your body produces or regulates its hormones. Phthalates are a class of chemical used to make plastic containers and materials more flexible. They're also added to personal care products to keep fragrances from fading. Research has linked phthalates to diabetes, breast cancer, and obesity. BPA is used in the lining of cans and plastic food containers, and also in many hard plastics. (Use this simple tool to find out if it's in your food.) It's tied to heart disease, anxiety, and a host of other diseases.
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So even if these chems didn't hurt your vitamin D levels, you'd want to watch out for them. How can you do that? It's not easy, Meeker says. These chemicals are everywhere. "However, it is possible to reduce exposure by limiting [your] use of plastic-containing products, finding natural alternatives to personal care products, and limiting consumption of heavily processed and packaged foods."
Basically, try to buy and eat unpackaged whole foods whenever possible. (Even BPA-free cans or plastics may not be any safer for you.) There are some nontoxic "green" home cleaning products that can cut down your chemical exposures. Shopping for fragrance-free cosmetics and other body care products can also help you avoid phthalates. The Environmental Working Group has a database with information on chemicals in cosmetics and personal care products, as well as lots of other resources to help you dodge phthalates and BPA.
While getting more D through sun exposure, diet, and supplements could also help, it's not clear if increased amounts of D can break through the chemical firewalls phthalates and BPA erect between your body and the vitamin it needs. For now, your best bet is to cut down your exposure to these chemicals.
This article was originally published by our partners at Prevention.