BPA, or bisphenol A, is a chemical found in some plastics and epoxy resins. If you look for the recycle number 7, you'll know that the plastic you're using contains BPA. BPA can also be found in some dental sealants, canned food linings, baby bottles, and medical devices.
The media frequently reports on concerns over BPA, and you can find BPA-free water bottles for sale (usually at a high price) in most sporting goods stories. Are these BPA-free products worth it? Is BPA dangerous for your health?
Here is what UpToDate, an electronic reference for doctors and patients, has to say about BPA:
"Concerns about health effects derive from animal studies that showed that BPA acts as a weak estrogen in the body and can impact biological systems at low doses. As an example, animal studies reported that low levels of exposure to BPA during development could cause changes in behavior, the brain, prostate gland, mammary gland, and the age at which the female animals attain maturity .
"Epidemiological studies have also suggested human health effects, including diabetes, cardiovascular disease, liver abnormalities, and abnormal semen parameters. Further investigation is needed."
Estrogen and BPA
BPA is a known endocrine disruptor. Endocrine disruptors are chemicals that have an effect on the hormones in our bodies, either by interfering with how they work in the body or by mimicking the hormones in the body.
BPA mimics estrogen, an important reproductive hormone. While estrogen is often thought of as the female hormone, the hormone is important for both men and women.
BPA acts like a weak estrogen in the body, and at least in animal studies, it has been found to have an effect even at low levels. Research has found that when animals are exposed to BPA at key developmental stages, the risk of negative effect is higher. This includes the fetal stage and animal infant stage.
BPA in Humans
We don't really know if the animal studies reflect how humans will react to BPA levels. However, it's best to be cautious when possible, and the National Institute of Environmental Health Sciences (NIEHS) suggests that avoiding BPA exposure when pregnant or breastfeeding.
But what about adult BPA exposure? Can it lead to problems with fertility? The NIEHS reports that according to the current research, there is negligible concern for BPA harming fertility in healthy adults, who are not working with BPA products in a work environment. (For those that do work directly with BPA materials, they rate the risk as minimal.)
Some small studies have found a possible link between BPA and fertility. In one study, men with detectable levels of BPA in their urine were three times as likely to have lowered sperm concentration and sperm vitality, more than four times likely to have lower sperm counts, and twice as likely to have lower sperm motility (how well the sperm swim). This study mainly concentrated on men who work with BPA in factories, and so it's unclear how this would relate to men who did not work with BPA in a work setting.
In a small study that looked at women going through IVF, researchers found that the higher the BPA levels, the lower the peak estradiol levels were. They also found that fewer eggs were retrieved in women who had higher levels of BPA.
Because these studies have been small in size, however, it's unclear how much impact BPA really may have on fertility and human health.
Some studies have found that 90% of the population has detectable levels of BPA in their urine. Considering that 90% of the population does not deal with infertility, the evidence doesn't seem to show a direct connection between BPA and infertility.
However, given that some preliminary studies have found an impact on fertility levels, it's probably best to avoid BPAs when possible.
Some ways you can lower your exposure:
Reduce the amount of canned foods you use. Instead, try to buy food that comes in glass jars (or fresh or frozen foods.)
Avoid cooking your food in plastic containers, as you might do when microwaving. Use glass instead.
Avoid plastic food containers, water bottles, and other plastic bottles that have the recycle number 7 on them. These are likely to contain BPA. Do not reuse water bottles that are meant to be disposable.
Talk to your dentist about BPA-free fillings.
More on protecting and improving your fertility:
- Quiz: How Fertility Friendly Are Your Health Habits?
- Folic Acid for Fertility
- Are There Specific Diets to Help Fertility?
- How to Start Improving Your Health
- 10 Tips to Increase Male Fertility
- 8 Bad Habits to Break to Improve Fertility
- Mind-Body Therapies for Fertility
- Female Smoking and Fertility
- Male Smoking and Fertility
- Your Weight and Your Fertility
- BMI Calculator
- Caffeine and Fertility
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Goldman, Rose. Occupational and environmental risks to reproduction in females. UpToDate.com. Accessed April 20, 2011.
Mok-Lin E, Ehrlich S, Williams PL, Petrozza J, Wright DL, Calafat AM, Ye X, Hauser R. Urinary bisphenol A concentrations and ovarian response among women undergoing IVF. International Journal of Andrology. 2010 Apr;33(2):385-93. Epub 2009 Nov 30.