Bispenal A (BPA)

Hormone Disrupter

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BPA in many plastic containersThere remains an ongoing debate about the safety of BPA, found in plastic bottles, food and beverage can linings, other food containers and products. On one side, government-funded studies suggest this compound contaminates our food and beverage to such an extent that they interfere with our hormones and even our epigenome, increasing risks of certain types of cancers and obesity, not only for the individual, but possibly for his/her off spring. On the other side, chemical company funded studies claim no such negative health effect.

Health Concerns

  • Bisphenol A is suspect of being linked to several human epidemics
    • Cardiovascular Disease (PLoS ONE, Jan 13, 2010)
    • Type 2 diabetes
    • Breast and prostate cancers
    • Enlargement of prostate
    • Early onset of puberty
    • Obesity (Masuno 2002)
  • Bisphenol A is hormonally ‘active’.
    • It has an effect in cells at levels thousands of times lower than toxicology reports had previously deemed safe (Nagel S)
    • Unlike phytoestrogens such as those found in soy beans, bisphenol A does not bind to blood proteins, which normally acts like a barrier, keeping estrogens from entering the cell.
    • Bisphenal A has been shown to stimulate human breast-cancer cells to proliferate in vitro (Welshons W)
    • Bisphenal A has been shown to enlarge prostates in mice at dosages close to what humans are exposed to from sources such as food packaging (Nagel S, Environmental Health Perspectives, National Institute of Health, 1997)
    • Bisphenol A has been shown to lower sperm counts in mice (Nagel S, 1997)
    • Increased prevalance of obesity if exposed to BPA as a fetus (Rubin 2009)

Exposure

  • Bisphenol A enters body
    • Digestion of contaminated water and food
    • Inhalation, entering through lungs
    • Skin contact (same way birth control does in patch form)
    • Mother’s blood stream to fetus
  • Studies by the CDC found bisphenol A in the urine of 93%-95% of Americans (Calafat 2005, 2008)
    • Suggests people are exposed regularly since bisphenol doesn't stay long in the body
    • Canned foods account for the greatest exposure of BPA (Environmental Working Group)
  • Products containing bisphenol A
    • Plastic water bottles
    • Plastic food storage containers (ScienceNews, Aug 28, 2010)
      • US Food and Drug Administration approved BPA for use in food containers in 1963
      • Over a decade later, federal law required safety reviews for new chemicals
    • Plastic baby bottles (transparent plastic)
      • detachable nipples have also been found to contain trace amounts of bisphenol A (Vom Saal)
    • Plastic resin in canned foods and aluminium beverage containers (Consumer Reports, Dec 2009)
      • BPA has even been detected BPA-free cans (Consumer Reports, Dec 2009)
    • Food containers from recycled paper (Ozaki)
    • Dental sealants, CDs and Toys, PVC pipe, medical equipment (Consumer Reports, Dec 2009)
    • Impact-resistant plastics such as safety helment, bulletproof glass, traffic signals, computer cases (ScienceNews, Aug 28, 2010)
    • Cash register receipts (ScienceNews, Aug 28, 2010)
      • Found in approximately 80% of receipts (Enviornmental Working Group, 2010)
    • Recycled paper
      • Gehring, et al. (2011). Bisphenol A contamination of wastepaper, cellulose and recycled paper products, WIT eLibrary, 08 March 2011
  • The rate of bisphenol A leaching from plastic containers into foodstuffs is accelerated by
    • Contact with lipids, such as those found in milk, formula, cheese, meat, and vegetable oils
      • bisphenol A links to lipid molecules
    • Contact with acidic foods, such as fruit juice
    • Repeated washings
    • Exposure to heat or sunlight (Belcher)
  • Other environmental contaminants
    • Plastic pollutants in our lakes, streams, and oceans
    • Bisphenol A found in water
      • suspect cause of unusually high instances of hermaphrodism in wildlife (Tillitt D)

Food Cans lined with Plasticisers

Recommendations

  • Elimenated consumption of foods from plastic lined cans
  • Avoid canned beverages including canned soda and beer
  • Avoid plastic food packaging and storage
  • No plastic of any kind should be placed in heat, particularly the microwave (National Toxicology Panel)
  • Avoid putting plastics in the dishwasher or using harsh detergents. Instead use warm soapy water. (National Toxicology Panel)
  • Choose foods in glass bottles instead of plastic or metal containers with plastic liners
  • Soy foods, containing a natural estrogens, may offer limited protection
  • Avoid prolonged skin contact with cash register reciepts and plastics containing PVC (ScienceNews, Aug 28, 2010)

Research and Politics

  • A review of the 115 published studies on bisphenol A found 90% of government studies found adverse low dose effects of bisphenol A. Interestingly, no studies funded by the chemical industry found any effect (Vom Saal F & Hughes C, 2004).
  • Chemical companies have infiltrated our government agencies and scientific communities
    • In 1996, Congress passed the Food Quality Protection Act and the Safe Drinking Water Act. It mandated the EPA to begin protecting consumers from endocrine disrupting chemical such as those found in pesticides and plastics by the year 2000
      • The US Environmental Protection Agency has been ineffective in protecting the public from bisphenol A.
      • Although scientists make up part of the panel of experts to advise the EPA on chemical screening, representatives of the chemical industry were also invited.
      • The chemical companies were permitted to choose how they would carry out the tests
        • (Eg: using a particular breed of rat and feeding rats a chow that contains soy, a natural estrogen).
      • In 1998 a House committee began investigating the rumored conflicts of interest in the scientific panels advising the EPA
    • In 1997, Center for the Evaluation of Risks to Human Reproduction (part of the US National toxicology Program) assembled an expert panel on bisphenol A
      • Scientists not were permitted to be apart to the CERHR panel if they had published a study on bisphenol A
      • The CERHR panel was ultimately discredited and disbanded when it was discovered that Sciences International, the company contracted to write the CERHR reports, had been funded by more than 50 chemical companies, including Dow Chemical (Cone M, Los Angeles Times, 7 March 2007).
    • On late 1997, A representative from Dow Chemical (one of the largest producers of bisphenol A) reportedly offered Missouri University research funding in exchange for Vom Saal, Nagel, and Welshon to withhold publishing their research findings until authorized to do so by the Chemical Manufactures Association. Vom Saal’s team rejected the offer.
      • Subsequent studies performed by independent labs (other than MU or those funded later funded by the chemical industry) confirmed the hormonal activity of bisphenol A
        • A study conducted at the department of pharmacology at University of Pittsburgh discovered mice that had been exposed to bisphenol A before birth had permanently enlarged the prostates (Gupta C, 1999).
        • At the University of Berlin, Gilbert Schonfelder (2003) detected bisphenol A in the human blood of pregnant women and in the placenta and umbilical cord blood of their babies
          • Babies are the most sensitive to the hormonal effects of bisphenol A (Welshon)
      • Dr Fred Vom Saal has featured in PBS Frontline and ABC's 20/20 and has testified in front of state legislators regarding bisphenal A.
        • In an interview with PBS, Dr Vom Saal explained:
          • If we were dealing with a topic that didn't have incredible economic consequences, there wouldn't be the kind of resistance to what we're talking about right now.
        • His 'Endocrine Disrupters' team (including Welshons and Nagel) at Missouri University (2008) studied the link between bisphenol A and obesity.
    • In March 2008, a congressional inquiry found the FDA’s conclusion bisphenol A is safe was based on only two studies, both sponsored by the Society of the Plastics Industry, a subsidiary of the American Chemistry Council

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