Bisphenol A has only garnered public attention in the last decade though we have largely been exposed to it since the 1950s. Canada has declared it a toxic substance. The American Medical Association has been calling for Congress to restrict its use in the United States. Many studies have been undertaken to determine its safety, with alarming results.
Bisphenol A is a substance found in polycarbonate plastics and is more commonly known as BPA. Most of our exposure is through food or cigarette smoke, but it is also used to coat paper to prevent ink smears and is common on thermal paper used for cash registers and credit card receipts. It seeps into our foods through plastic water bottles and other types of food containers marked with a 3 or 7. It is also found in the epoxy resin used to line metal food cans, soda cans, and bottle tops, as well as some dental sealants.
BPA is an endocrine disruptor that mimics the hormone estrogen. It has been linked to many common health afflictions, including fertility issues, birth defects, early puberty, cancer and resistance to chemotherapy, neurological issues, increased sensitivity to drug abuse, heart disease, obesity, and diabetes. What is alarming is that studies have shown BPA to be more toxic in low doses than in high doses.
BPA is a real concern, as it can alter the behavior of over 200 genes. It has been linked to fertility problems in humans, including an increased risk of miscarriages. It potentially affects the development of the prostate gland in fetuses, infants, and young children. Studies have shown it to affect the quality and number of eggs of females, as well as chromosomal and reproductive abnormalities of the population as a whole. In studies involving rats, exposure to BPA during pregnancy increased the risk of offspring developing breast cancer and prostate cancer as adults.
BPA has been shown to cause impaired brain and neurological functions and has been linked to some cases of Down’s syndrome. It has also been linked with anxious, depressive, and hyperactive behaviors in 3-year-old girls, with more prominent effects correlating with higher BPA levels in the urine. In a 2008 Yale study using primates, BPA exposure showed adverse neurological effects to occur at levels equal to the dose considered safe for humans by the United States Environmental Protection Agency (EPA). BPA was shown to cause the loss of connections between brain cells in the parts of the brain involved with regulating memory, learning, and mood. According to the findings, BPA could interfere with memory formation, inhibit learning, and contribute to depression.
Scientists also believe BPA may be involved in arterial narrowing. Two separate studies published in the Journal of the American Medical Association (September 2008 and January 2010) plus a third study published in August 2012 in PLoS ONE, found an increased risk of coronary heart disease associated with BPA. Researchers found the more severe the coronary artery disease, the higher the levels of BPA in the urine.
Studies by other scientists showed BPA causes insulin resistance in mice by disrupting pancreas function leading to type II diabetes. In another study, pregnant mice were given BPA during their pregnancy and lactation period. After weaning, the babies were exposed to the BPA through their drinking water. At 31 days old, the offspring were checked. The BPA-exposed mice accumulated considerably more fat tissue than the non-BPA-exposed mice and had high levels of fat in their blood, known as hyperlipidemia. One of the causes of hyperlipidemia is diabetes.
Though it is still in widespread use, BPA has been shown through more and more studies to have adverse effects on our health. Scientists around the globe have seen increasing evidence that BPA is linked to all the above-listed health conditions and have been discovering more. While it is not possible to completely avoid exposure, limiting your exposure to the above-listed products would be a great way to start.
Resources:
http://www.ewg.org/reports/bisphenola
http://pediatrics.aappublications.org/content/early/2011/10/20/peds.2011-1335
http://jama.jamanetwork.com/article.aspx?articleid=182571
http://www.nlm.nih.gov/medlineplus/news/fullstory_128283.html
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0043378
http://news.yale.edu/2008/09/03/more-evidence-bpa-found-clear-plastics-impairs-brain-function
http://www.breastcancerfund.org/assets/pdfs/tips-fact-sheets/bpa-abstracts.pdf
