Is Your Raincoat Making You Fat?

By December 6, 2018Environment, Health


Is Your Raincoat Making You Fat?

By Stewart Lonky, MD

Is your raincoat making you fat?

Perhaps not as much as a jelly donut or plate of French Fries, but new research hints that chemicals lurking in everything from waterproof clothing to furniture may play a role in both weight gain and weight retain.

Widely used manmade chemicals called perfluoroalkyl substances (PFAS) may undermine our attempts to lose weight and keep it off by slowing down the body’s metabolism and even changing the way our bodies burn and store fat.

Perfluoroalkyl and polyfluoroalkyl substances, also known as “highly fluorinated chemicals,” are a class of persistent compounds used to add nonstick, waterproof, and/or the parental favorite stain-resistant properties to clothing, furnishings, carpeting, cookware, food contact paper, cosmetics, and other consumer products. They are also used in firefighting foams and industrial processes. Perfluoroalkyl substances are both water- and oil-repellent, explaining their widespread use.

Of the many chemicals that fall into this category, the so-called “long-chain” PFAS perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been most extensively studied. In fact, hundreds of credible scientific articles have been published on the toxicity of these two chemicals. Because of their ubiquity, persistence, and mobility, they have been detected in the blood of nearly all Americans tested. The drinking water of at least 6 million American residents is known to be contaminated at levels exceeding a 2016 US Environmental Protection Agency lifetime health advisory.

While studies don’t prove a direct cause-and-effect—correlation doesn’t equal causation— Harvard School of Public Health assistant professor of nutrition Dr. Qi Sun noted in prepared press release that people with higher blood levels of PFAS had more difficulties of maintaining weight loss after dieting, and that this pattern was most noticeable in women. The reason why women might be more vulnerable still isn’t known, but researchers suspect that hormones might play a role. In particular, PFAS could interfere with estrogen metabolism and functionality (estrogens help regulate body weight and metabolism).

According to Dr. Sun, these chemicals are persistent, ubiquitous, and “detectable in blood in most U.S. residents.” These chemicals have variously been linked to cancer, hormone disruption, fertility problems, immune dysfunction, high cholesterol, and telomere shortening, a key determinant in healthy aging and lifespan, both in animals and humans.

Some Good News…

While PFAS, along with many other endocrine disrupting chemicals are present in the environment and our consumer products, making them impossible to avoid completely, another Harvard-supported study, published in JAMA Network Open, found that other obesity risk factors magnify PFASs endocrine/obesogenic effects, but are negligible, and even non-existent, when positive lifestyle interventions such as physical activity and a healthy diet are introduced.

While it’s challenging to entirely avoid exposures to these PFAS and other endocrine disrupting chemicals, there are some common sense approaches you can take to limit exposure. They include:

  • Eliminating, or at least limiting fast and/or microwaveable food. Since PFAS chemicals have water- and oil-repellant properties, they’re valuable to the fast-food industry and for packaged foods. In a 2017 study published inEnvironmental Science & Technology Letters, researchers found that about half of the 400 food wrappers and containers they analyzed contained fluorine, an indicator of PFAS. If you still insist on packaged or fast foods, take the food out of the wrapper as quickly as possible, particularly if you plan on using a microwave oven.


  • Limiting your use of stain and/or water-resistant products. Another common use for PFAS is making clothing, carpets, upholstery, and other textiles stain- or water-resistant. The grape juice your kids spill on the sofa doesn’t magically evaporate. To be safe, avoid as much as possible stain-, water-, soil-, or grease-repellant products. And whenever possible—in the case of a raincoat, for example—look for gear labeled “PFAS-free” or “fluoro-free.”


  • Watching out for nonstick cookware. Most of us own nonstick cookware, so I don’t want you to throw it away—unless it’s badly scratched or damaged. However, consider new cookware that’s PFAS-free. Anything made with stainless steel, ceramic or cast-ion will do the trick.


  • Going easy on seafood. Since they’re prevalent in the environment, PFASs typically accumulate in the tissue of animals that we humans consume for food. These chemicals are especially common in seafood. If you’re concerned about PFAS exposure, follow the same rules for limiting your mercury and heavy metal intake by choosing fish that are lower on the food chain like salmon. However, some lower food chain animals, such as lobster and crab, are high in PFAS and heavy metals.


  • Minding your water supply. PFAS released during industrial and manufacturing processes can also accumulate in water supplies, especially near industrial sites, wastewater treatment plants, and military fire-training areas. Anyone concerned about contaminant levels can also install activated carbon filters in their homes. These products do a fairly good job at removing a lot of these chemicals from drinking water.


  • Lowering your obesity risk factors. Since the obesogenic effect of PFAS increases in the presence of other known obesity risk factors, consider some easy-to-follow lifestyle interventions that can lower your weight, including regular exercise and a healthy diet.

So, while I don’t suggest you toss your raincoat or nonstick pans just yet, it’s always a good idea to think about what you put on, in, and around your body.





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