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What is BPA?

21 Jan

Toxins in Plastics

(source)

What is BPA and what is it in?

Bisphenol A (BPA) is a chemical  that is used mainly to produce polycarbonate plastic and epoxy resins (source).  Over 6 billion pounds of it are produced annually and over 100 tons are released into the atmosphere by this production (source).

BPA can leach from polycarbonate baby bottles (source) and reusable water bottles (source).

Reusable food containers have also shown to have BPA residue (source).

BPA has also been found to leach from residues of cans into foods such as pet foods, vegetables, fish and  infant formula (source).

What studies have been done on BPA?

Early studies aimed to determine if BPA is even in humans’ bodies:

  • Since 1999, more than a dozen studies have measured free, unconjugated BPA concentrations in human serum at levels ranging from 0.2–20 ng/ml (source).
  • BPA in the serum of pregnant women, umbilical cord blood and fetal plasma (source) indicates that BPA crosses the maternal-fetal placental barrier.
  • BPA has also been measured in human urine from several populations around the world.
  • A recent CDC study of over 2500 Americans found BPA in 92.6% of the participants (source)!!!

Studies have also been done BPA to determine if BPA is toxic to humans.  The majority of these studies have been done in animal models.

  • BPA was shown to act like estrogen in mice and produce estrogen-senstive responses  (source)
  • There is some evidence that BPA can prevents the thyroid hormone from binding to its receptor (thus inhibiting the thyroid hormone) (source)
  • However, other studies have found that BPA does not have estrogen-like activity and does not inhibit thyroid binding  (source) (source)
  • The anti-androgenic (sex hormone)  properties of BPA are still in dispute (source)
  •  in utero (in the womb) exposure of animals to low dose BPA can induce alterations in estrogen-target organs of the fetuses that are observed later in life (source)( source).

What is the government doing about it?

The  Chapel Hill Consensus was formed in August 2007 to determine the risk of BPA to human health.  38 authors penned a statement:

“The published scientific literature … reveals that human exposure to BPA is within the range that is predicted to be biologically active in over 95% of people sampled. The wide range of adverse effects of low doses of BPA in laboratory animals exposed both during development and in adulthood is a great cause for concern with regard to the potential for similar adverse effects in humans … There is extensive evidence that outcomes may not become apparent until long after BPA exposure during development has occurred … These developmental effects are irreversible and can occur due to low-dose exposure during brief sensitive periods in development, even though no BPA may be detected when the damage or disease is expressed” (source).

In 2008, the National Toxicology Program Center For The Evaluation of Risks To Human Reproduction (CERHR) released its stance on BPA:

  • The NTP has some concern for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A.
  • The NTP has minimal concern for effects on the mammary gland and an earlier age for puberty for females in fetuses, infants, and children at current human exposures to bisphenol A.
  • The NTP has negligible concern that exposure of pregnant women to bisphenol A will result in fetal or neonatal mortality, birth defects, or reduced birth weight and growth in their offspring.
  • The NTP has negligible concern that exposure to bisphenol A will cause reproductive effects in non-occupationally exposed adults and minimal concern for workers exposed to higher levels in occupational settings (source)

The FDA up until 2008 did not consider BPA to be harmful to humans.  However, it was then leaked that a retired medical supply manufacturer (and thus a link to BPA usage), Charles Gelman, gave $5 million to the research center of Martin Philbert (the chair of the FDA panel about to rule on BPA’s safety) (source).

If you now go to the FDA’s website, you will find that they are:

At this interim stage, FDA shares the perspective of the National Toxicology Program that recent studies provide reason for some concern about the potential effects of BPA on the brain, behavior, and prostate gland of fetuses, infants and children.  FDA also recognizes substantial uncertainties with respect to the overall interpretation of these studies and their potential implications for human health effects of BPA exposure.  These uncertainties relate to issues such as the routes of exposure employed, the lack of consistency among some of the measured endpoints or results between studies, the relevance of some animal models to human health, differences in the metabolism (and detoxification) of and responses to BPA both at different ages and in different species, and limited or absent dose response information for some studies.

FDA is pursuing additional studies to address the uncertainties in the findings, seeking public input and input from other expert agencies, and supporting a shift to a more robust regulatory framework for oversight of BPA to be able to respond quickly, if necessary, to protect the public.

In addition, FDA is supporting reasonable steps to reduce human exposure to BPA, including actions by industry and recommendations to consumers on food preparation.  At this time, FDA is not recommending that families change the use of infant formula or foods, as the benefit of a stable source of good nutrition outweighs the potential risk of BPA exposure.

(source).

How can I avoid it?

The first step to avoid BPA is to educate yourself about possible sources of BPA in your and your family’s life:  canned foods, old plastic bottles, etc.  Reduce the use of these materials, if possible.

According to the EWG, here are some sources of high BPA exposure (you can also read much more in-depth about BPA on EWG’s website)

Question?

How do you avoid BPA?  How do you feel about the fact that individuals with links to BPA can influence the ruling on whether BPA is safe or not?

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