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An Update on BPA

By on September 19th, 2014 Categories: Uncategorized

Bisphenol A, or BPA, has been in the news a lot lately. It is a manmade chemical used in many rigid plastics, the lining of food cans, cashier receipts, and other products since the 1960s. BPA is being phased out because it is a hormone disruptor. That means it may mimic or block a hormone or affect how natural hormones, such as estrogen, behave in the body. Because estrogen can make hormone-receptor-positive breast cancer develop and grow, many women try to limit their exposure to these chemicals.

A wave of new studies published in the past year offers more evidence that BPA is more problematic than we once thought. I’m especially concerned about the reproductive health risks linked to BPA. I’ve written about BPA before, but based on the latest research, I’d urge you to make an extra effort to avoid it.

You may have heard that the U.S. Food and Drug Administration (FDA) recently concluded that BPA is safe in the small amounts used in food packaging. Federal agencies are very conservative about making changes to their recommendations (BPA was first regulated in the early 1960s) and in banning products. My concern is that even low-level exposure over a lifetime could have a negative effect on health.

When it comes to prevention, it’s best to follow the Precautionary Principle. If something may pose a hazard, it’s better to be safe than sorry. Based on that principle, the European Food Safety Authority has temporarily lowered the tolerable daily intake of BPA to just 5 micrograms per kilogram of body weight per day, down from 50 mg/kg/d. And U.S. lawmakers have introduced bills to ban BPA from food containers in both the House (HR 2248) and the Senate (S.1124).

Where is BPA found?

Everyone is exposed to some level of BPA because it’s in so many everyday products. Unfortunately, it’s also in most of us. A recent study of 2,000 pregnant Canadian women found BPA in the bodies of 88% of them.

The main source of BPA exposure is through what we eat. That’s because BPA comes in contact with the food inside plastic or cans (and other metal containers) at the grocery store. It’s also found on the back of those thermal paper receipts the clerk hands you at the checkout counter. Elevated levels of the chemical have also been found in garden hoses, and a small amount of a BPA derivative called bisGMA is used in dental sealants, including composite fillings.

BPA is rarely found in baby bottles and children’s sippy cups anymore because manufacturers decided to stop using it. Just in case, the FDA banned it from those products in 2012. It’s a good thing, because children and adolescents are more sensitive to the effects of BPA than adults.

Latest findings

Besides disrupting hormones, BPA has been found to cause metabolism and immune system problems. Animal and cell studies of BPA at different exposure levels have linked it to:

  • heart disease
  • obesity
  • diabetes
  • disorders of the nervous, immune, and reproductive systems
  • cancers of the breast, brain, and prostate

The seriousness and uncertainty of these findings led scientists to take a closer look at BPA. In 2009, the National Institutes of Health’s National Toxicology Program coordinated a $30 million research program on BPA’s effects. Meanwhile, other scientists have completed some of the first studies using human subjects and human cells. Researchers have also been tracking BPA levels in people’s blood and urine and paths of exposure to the chemical.

BPA and breast cancer

New research has found that BPA can harm breast cells, and scientists are starting to understand how that happens. For example:

  • A study on breast cancer cells found that BPA can work with natural estrogen in the body to interfere with the genes that are supposed to stop cancer from developing and growing.
  • Another study looked at the effect of several manmade chemicals, including BPA, on breast cancer cells. It found that BPA, at levels typically found in human blood, encourages the growth and spread of inflammatory breast cancer. Inflammatory breast cancer is a rare and aggressive form of the disease. (The study found these effects for both estrogen-receptor-negative and estrogen-receptor-positive cancers.)
  • In the same study, the scientists also found that BPA made inflammatory breast cancer cells resistant to standard treatment. They believe the chemical’s ability to speed up cancer growth canceled out the effects of the drugs used to stop it.

Past animal research linked BPA exposure to several types of reproductive health problems in female rats. More research now suggests that BPA creates permanent genetic changes in the developing mammary glands of baby rats exposed to BPA while they were still in the womb. These changes made them more likely to develop breast cancer later in life.

Reproductive health

BPA seems to affect reproductive organs in both women and men. The research suggests that these effects may touch not only those exposed to BPA, but also their children and grandchildren.

Two broad reviews of BPA and the female reproductive tract were published this year. Both of them looked at laboratory and human data together, and both found the chemical to be harmful to the reproductive system and/or the fetus. That means BPA may cause problems with getting pregnant and having a healthy, full-term baby. The effects were found at both levels the government considers safe and at doses lower than that.

The strongest evidence from these overviews suggests that BPA exposure may:

  • Harm the development and function of the ovaries in several ways, such as lowering the quality of egg cells in both animals and humans. The level of effect BPA has depends on when you’re exposed to the chemical. The scientists involved think BPA may play a role in infertility.
  • Harm the uterus in animals. BPA seems to affect the womb’s ability to perform its normal functions. Human studies on this effect are less certain.

There is also limited evidence that BPA exposure may:

  • affect the course and outcome of a pregnancy
  • be linked to hormone-related disorders such as polycystic ovary syndrome
  • interfere with the success of in vitro fertilization (medically assisted pregnancy) by preventing the embryo from implanting in the womb

A small, recent study of women in the first few months of pregnancy measured levels of BPA in the women’s blood. The results are very concerning. Researchers found that the risk of miscarriage was 83% greater in women with the highest levels of BPA compared to women with the lowest levels of BPA.

You can’t make babies without sperm, and BPA may be a cause of male infertility as well. Scientists looking at data trends suspect that endocrine disruptors are playing a role in men’s health problems, including widespread drops in sperm counts.

New research has found that BPA exposure may:

  • be linked to changes in levels of the hormone testosterone, even at very low levels of BPA exposure (human testosterone was found to be 100 times more sensitive to BPA than lab animal testosterone)
  • be harmful to testicle function in animals (the testicles produce sperm)
  • cause sexual dysfunction in men

Other findings

As I mentioned, BPA has been linked to male reproductive health problems. Recent studies of men’s exposure to BPA found that men with prostate cancer also had much higher BPA levels in their urine. Lab studies exposing prostate cells to BPA found it caused high rates of cell abnormalities, and studies of mice exposed to BPA found the animals later developed high rates of prostate cancer.

There’s also more evidence suggesting BPA is linked to weight gain, including obesity in children. Researchers also found a tendency to gain more weight over time in women with higher BPA levels.

An important note about BPA alternatives or substitutes

Reports strongly suggest that new alternative plastics are no safer than BPA and may even be less safe. A “BPA free” label doesn’t always mean the material is harmless. The Oregon Environmental Council has a list of possibly safer alternatives.

How to protect your and your family’s health

Again, the Precautionary Principle is important. There’s lots of advice in my 2012 column Avoiding Bisphenol A. There are also tips in Kids and Chemicals in Plastic: What Are the Risks?

In addition to those steps, you can:

  • Use glass! Drink from a glass. Buy food and drinks in glass jars. Reuse your jars for food storage and for transporting your beverages.
  • Use a metal or glass water bottle.
  • Steer clear of canned and plastic-packaged foods by eating and cooking more fresh foods (hello, farmers’ market!) or buying only those sold in glass containers.
  • Wear protective (non-allergenic, non-vinyl) gloves if you handle a lot of receipts. New research shows BPA can enter our blood through skin contact. Or wash your hands after handling the receipts.
  • Don’t drink from garden hoses. Chemicals in the materials hoses are made of can leach out into your hands and into water flowing through them. Store your hose in the shade to prevent leaching, or buy a low-hazard rubber one. The HealthyStuff.org site rates home products for toxicity.
  • If you need dental work, ask your dentist about alternatives to white composite resin or other BPA-based materials. But don’t choose mercury-containing silver amalgam fillings! Mercury is a naturally occurring metal that is toxic at high doses and can harm the nervous and reproductive systems. It’s not necessary to remove the sealants you already have, but get regular checkups to ensure they are intact. Most of all, take good care of your and your children’s teeth by brushing and flossing regularly.

Marisa Weiss, M.D. is the founder, president, and chief medical officer of Breastcancer.org, the world's most trafficked online resource for medically reviewed breast health and breast cancer information, reaching over 14 million visitors per year. A breast cancer oncologist with over twenty years of active practice in the Philadelphia region, Dr. Weiss is regarded as a visionary advocate for her innovative and steadfast approach to informing, empowering, and treating patients with breast cancer.

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