BPA: still a big deal

Bisphenol A is everywhere. And research suggests that it’s not doing your health any favors.

Endocrine disruptors are chemicals that can interfere with estrogen, testosterone, thyroid hormone, insulin, or other hormones. At very low levels, they can turn on, shut off, or alter the signals that the hormones send throughout our bodies. And that can spell trouble.

BPA is an endocrine disruptor that’s used to make polycarbonate, a hard plastic, and to protect the insides of cans, jar lids, and bottle caps. It also coats printed receipts from cash registers, gas pumps, and ATMs.

So it’s no surprise that nearly all of us have BPA in our bodies. Researchers report that tiny amounts of BPA cause subtle changes in fetal and newborn lab animals.

“If these kinds of changes occur in human infants, they might increase the risk of birth defects or infertility and cancer later in life,” says NC State biology professor Heather Patisaul.

Mothers with high levels of BPA in their urine during pregnancy, notes Patisaul, have children who are more likely to suffer from behavioral problems than the children of mothers with lower levels.1

Like most research on humans and BPA, that kind of study can’t prove cause and effect, but it’s troubling nevertheless.

Adults

Is BPA harmful to adults? It’s not clear. “But there are certainly hints in the research,” says Patisaul.

Some of the evidence:

Obesity. Researchers monitored the weight of nearly 1,000 nurses after they provided urine samples for BPA testing. After 10 years, the women who entered the study with the highest BPA levels gained an average of five pounds more than those with the lowest levels.2

Type 2 diabetes. Giving BPA to grown animals leads to greater insulin resistance in some studies.3 (Insulin allows blood sugar to enter cells. If your cells become resistant to insulin, you have an increased risk of type 2 diabetes and heart disease.) What about humans? Middle-aged U.S. nurses who had the highest levels of BPA in their urine were twice as likely to later be diagnosed with type 2 diabetes as nurses with the lowest BPA levels.4  However, that wasn’t true for nurses in their 60s and 70s. “The younger women, who have not experienced menopause, may be more vulnerable to endocrine disruptors than older, postmenopausal women,” says Qi Sun, an assistant professor in the department of nutrition at the Harvard T.H. Chan School of Public Health.

Heart disease. In an 11-year study of nearly 1,500 people in the UK, those with higher BPA levels in their urine at the start were 11 percent more likely to later be diagnosed with heart disease than those with lower levels.5  But the increased risk wasn’t quite statistically significant, so it could have been due to chance.

Cancer. “It is clear that BPA can act as an estrogenic compound,” says Ruth Keri, a cancer researcher at Case Western Reserve University. “So it is conceivable that BPA may promote the growth of any tumors that are driven by estrogens, such as breast cancers.” Exposing mice to BPA in the womb leads to an increase in breast tumors.6 “But there is much less research on exposure in humans and the impact that it can have on cancer susceptibility or growth,” notes Keri.

Culture Clash

Despite the emerging evidence suggesting that BPA may be harmful, the Food and Drug Administration has ruled that it’s safe.

“Governments rely on classic toxicology studies that are good at looking for gross signs of illness, such as organ failure,” says Patisaul. “But a lot of scientists believe that many of those studies are out of date because they don’t look for subtle effects that could contribute to chronic disease.”

For example, a classic way to look for harm to an animal’s brain is to weigh it. “That’s pretty crude,” Patisaul points out. “Your brain has to be really sick to change weight.”

Instead, she and others count the number of estrogen receptors in the brain, which drops when animals are exposed to BPA in the womb and at a young age.7

“I think it makes the brain more vulnerable to hormone-dependent changes that can affect behavior and mood, so I worry about it,” says Patisaul. “But the FDA doesn’t consider those changes a reason for restricting or banning BPA at the levels of current human exposure.”

Reducing Exposure

To minimize your exposure to BPA, avoid foods and beverages in cans. “BPA-free” cans and plastics may not be a get-out-of-jail-free card, though. Some researchers suspect that BPA substitutes may not be safe, either.

Click here for a printer-friendly version of the above infographic.

References

1NeuroToxicology 49: 174, 2015.
2Int. J. Obes. 38: 1532, 2014.
3PLoS One 7: e33814, 2012.
4Environ. Health Perspect. 122: 616, 2014.
5Circulation 125: 1482, 2012.
6Biol. Reprod. 85: 490, 2011.
7Toxicol. Sci. 140: 190, 2014.

Photo: © jat306/fotolia.com.

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14 Replies to “BPA: still a big deal”

  1. I am an office manager & input receipts from our techs so on a daily basis I am handling thermo receipts. Could this be a concern?

    1. I am not a scientist, I hope an expert replies, but now that we are aware that they have BPA, I would at least be careful to wash my hands after handling. I don’t know enough about exposure through the skin to suggest gloves; someone here may be able to evaluate options.
      In the 1980s, I worked for about 3 years as a bookkeeper with lots of NCR (no carbon required) multipart forms, in a poorly ventilated office. I am convinced that I developed an allergy from the exposure—there was no way to test for it, as the test would be carcinogenic—I tested positive for cats, dust mites, and kapok. After leaving the job, eventually my allergies decreased—I still react to fresh newsprint, though.

    2. It may be a concern, but we honestly don’t have enough data to say for sure. These are difficult studies to run in order to prove cause and effect. However, limiting exposure can’t hurt. If possible, wear gloves. If that’s not realistic, be sure to wash your hands regularly and especially after handling receipts and before eating or handling food.

    3. I use gloves every day as a dentist and here are some observations you may consider relevant.
      1. Assuming you are comfortable with the materials in your gloves (I’d suggest latex-free), gloves are themselves comfortable to wear and even dentists, who need fine finger-sensitivity with their gloves, do nicely.
      We change them at least once every patient. You might consider changing them when they are visibly soiled, when they tear, or perhaps every couple of hours. They may make your hands sweat if it is hot. Big deal.
      2. I can’t comment on whether gloves can protect the hands from chemicals, which may leach through. Nevertheless, gloves are considered an adequate barrier for microbial contamination including small viruses. I found I caught colds far less when I began using them (along with everyone else) routinely. If you let liquids spill into the gloves then all bets are off.
      3. If you elect not to wear gloves, please don’t touch any body opening when you handle possibly toxic objects. I carry a small piece of tissue to rub my nose if it itches (seeing people rub their nose with their fingers is yucky). I also cover cuts quickly and shave with an electric razor.
      4. If your environment raises dust you may consider a mask (preferably a 95-rated one).
      Yes, you may consider those suggestions overkill, but even with them you contact plenty of scary stuff during the day, so take care of your immune system, sleep and exercise enough, and drink plenty of water.

  2. I grabbed a screen shot of the graphic on dodging disruptors—O.K. to share? Is there a way to get copies to hand out? good info!

    1. Hi Sally,
      Yes, feel free to share (please give credit to Nutrition Action Healthletter when you do). We don’t have a hand-out prepared, but I’ll look into getting one. Thanks!

      1. Hi Sally,

        We’ve updated the post to include a link to a downloadable and printable infographic. Please look back at the post to find the link. Thanks for your interest!

  3. The data does not provide conclusive evidence. That is because partly in how the studies were designed. The evidence is not there to support “cause and effect” nor the “does and dears” data interpretation since the studies, again, were not designed to reflect on such. Like in drug does, “how many people benefit from treatment with this drug?” Often this is skewed because the number of individuals using the drug vs # using a placebo is small. However, later post marketing data reflects more on a total population of the drug use and is more accurate. So, studies for BPA studies need to be designed to reveal more specifics but on this topic, that will be difficult to establish a “cause vs adverse outcome.” So what does one do? As previous repliers have suggested, wash hands, limit exposure but don’t be overly concerned.

  4. Thanks for the helpful info! But, how to determine if a BPA-free can might be safe? What about jar lids? And how about the foil-lined pouches and cartons that beans and soup are packaged in? Is the only safe pre-prepared food frozen, I wonder?

    1. I’ll apologize in advance, because we don’t have an easy, clear answer for you! Unfortunately, many companies haven’t disclosed or properly tested the material they’ve replaced BPA with. That makes it impossible to say whether or not the replacements are any better than BPA, but this is what we’ve gathered.
      BPA can be in jar lids, as well as the tops that you pull off microwaveable soup bowls.
      As for the pouches and cartons that beans and soup are packaged in, we don’t know much about what they’re made from, but we do recommend switching to soups and beans in pouches, cartons, or cardboard containers, as that might lower your exposure to BPA (and maybe its “cousins”).
      We also recommend that you transfer all foods to glass bowls for microwaving or heat them in a pot on the stove to lower the odds that any chemicals in a package end up in your food.

    1. Thanks for your interest, Renee! We’ve made a printable version of the infographic. You can find the link for the download under the image in the updated post.

  5. Is it safe to put school aged children’s sandwiches in plastic wrap or baggies? I worry about even the BPA-free plastics.

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