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Sarah Janssen’s Blog

New study finds changes in diet affect BPA and phthalate exposure.

Sarah Janssen

Posted March 30, 2011 in Health and the Environment

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A new study published today in the scientific journal Environmental Health Perspectives found that dietary changes can reduce exposure to the endocrine disrupting chemicals, bisphenol A (BPA) and the phthalate, DEHP.

The study was done by my colleagues at the Breast Cancer Fund and Silent Spring Institute and followed five Bay area families for a week, monitoring their urine for the breakdown products of BPA and phthalates. The families ate their regular diet at the beginning and then were provided meals midway through the study which consisted of freshly prepared food with no plastic packaging.  After just 3 days of eating this diet, there was an average reduction of over 60% in their body levels of BPA and a 50% reduction in DEHP. At the end of the study, the families returned to their normal diets which included canned food and sodas, take-out or restaurant food, and other foods, such as microwavable meals, packaged in plastic. After resuming their regular diet their BPA levels went back up.

The study is novel in that no one has ever done an experiment like this in Americans. Federal agencies such as the FDA and National Toxicology Program have stated that food is a major source of exposure to BPA and phthalates but this is the first time a dietary intervention has demonstrated actual changes in exposure.

Bisphenol A (BPA) is used as an epoxy resin to line food and beverage containers. It is there to prolong the shelf life of the product by keeping the can from corroding due to contact with acidic foods and also prevents a metallic taste in the food. However, the resin is not inert and BPA is known to leach from the lining into the food. Today’s study identified the types of canned foods that are most often contaminated with BPA but it is also worth mentioning that liquid infant formula is also packaged in BPA-containers. BPA is also used as the building block of polycarbonate plastic which can still be found as reusable beverage containers and in some microwavable containers.  Both of these uses of BPA are approved by the FDA as “food additives”.

NRDC has previously sued the FDA over their failure to regulate BPA in food packaging. We are concerned about the widespread exposure to this chemical and the detrimental health effects which have been associated with exposure including a predisposition to breast and prostate cancer, altered development of the brain resulting in behavioral changes, and chromosomal abnormalities. Other studies have associated BPA with changes in metabolism resulting in a pre-diabetes condition (insulin resistance) and changes in fat distribution in the body.   

Phthalates are a group of chemicals which are used as plasticizers to soften hard plastics, create pliability, and several dozen different phthalates have been approved as food additives in food packaging and processing. They likely leach into the food during processing and packaging. This study only looked at a handful of those phthalates and found significant changes just in one, DEHP.  DEHP has been banned from children’s toys in the U.S. since 2009 but has not been banned from any other use in the U.S. DEHP has been banned in toys in Europe since 1999 and are also banned from cosmetic use in Europe.

Phthalates are of concern because they interfere with the synthesis of the male sex hormone, testosterone, and exposure early in development has been associated with birth defects of male genitals and later in life, poor sperm quality and infertility.

Though this was a small study of just 5 families and 20 participants, it is compelling because it demonstrates significant decreases in exposure with dietary changes.

This is something each of us can do and the benefits will go beyond reducing exposure to BPA and DEHP.

Eating freshly prepared food that is less processed and where available, organic, will reduce exposure to many other food additives, pesticides and is overall much healthier. The study authors have compiled other suggestions on how to reduce exposure which include eating in instead of at restaurants, not microwaving in plastic and using glass containers for food storage. All of these measures will reduce exposure but it isn’t enough. We need to government to ensure all food is safe.

What we really need is for the FDA to do their job of protecting public health by revoking approval of the use of harmful chemicals as food additives. Current levels of exposure, though small, are not safe and have been associated with a wide range of health effects in animal studies. Since there has not been any comprehensive testing of food in the U.S. for these chemicals, we can’t be sure which foods are the most highly contaminated. Eliminating their use would take the guesswork out of a trip down the grocery store aisle and would have significant public health impacts.

While NRDC continues to press the FDA to act, here are a few things you can do to reduce your exposure:

  • Limit your consumption of canned or processed food by eating fresh or frozen produce and buying processed food in "brick" cartons, pouches or glass.
  • Limit your consumption of canned soda and beer - where possible choose glass as an alternative.
  • If you have a newborn, avoid baby bottles or sippy cups made of polycarbonate (hard, clear, shatterproof) plastic. They are marked with the recycling symbol #7, and sometimes labeled "PC." (Not all #7 plastics are polycarbonates-the only way to know for sure is to call the manufacturer.)
  • Use a BPA-free reusable water bottle, such as an unlined stainless steel bottle.
  • Don't allow your children to have dental sealants made from BPA (or BADGE) applied to their teeth, and don't have these sealants applied to your teeth while you are pregnant. Ask your dentist to provide BPA-free treatments.
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Switchboard is the staff blog of the Natural Resources Defense Council, the nation’s most effective environmental group. For more about our work, including in-depth policy documents, action alerts and ways you can contribute, visit NRDC.org.

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