Episode 74 – BPAs: What the Heck Are They and Where Are They?
Bisphenol A (BPA)
- Organic, synthetic chemical. Colorless solid soluble in organic solvents but poorly soluble in water. Used since 1957.
- Used to make some plastics and epoxy resins. BPA plastics are tough & clear and used in a LOT of stuff!
- Water bottles
- sports equipment
- CDs, DVDs
- Coatings inside food & beverage cans
- Thermal paper (receipts)
- 2011 – 10 billion pounds of BPA chemicals synthesized for making polycarbonate plastic making it one of the highest volume of chemicals produced worldwide!!
- Edward Charles Dodds Tested as an artificial estrogen in the 1930’s. He later developed DES which was later banned
- Premarin – first identified in the late 1930s
- EU & Canada have banned BPA use in baby bottles
- FDA: “BPA is safe at the current levels occurring in foods”
- FDA: “BPA is a structural component in PC beverage bottles. It is also a component in metal can coatings which protect the food from directly contacting metal surfaces.”
- No longer authorized for baby bottles but it wasn’t due to safety. It was due to market abandonment.
- France: Feb, 2016 announced it intends to propose BPA as a REACH regulation candidate “substance of very high concern.”
- Endocrine society: 2015, results of ongoing lab research provided grounds for concern about potential hazards of endocrine-disrupting chemicals, including BPA, in the environment, and that on the basis of the precautionary principle these substances should continue to be assessed and tightly regulated.
- Chapel Hill Consensus Statement: BPA at concentrations found in the human body is associated with organizational changes in the prostate, breast, testis, mammary glands, body size, brain structure and chemistry, and behavior of laboratory animals.
- Average BPA levels in people were above those that cause harm to many animals in al experiments.
- Color developer in carbonless copy paper and thermal receipt paper. In thermal paper BPA is not polymerized and is available as free BPA making it more available for exposure. Upon handling, BPA is transferred to skin. Concern for hand-to-mouth exposure.
- How does it interact with estrogen?
- Structurally similar to Estradiol – allows BPA to trigger estrogenic pathways.
- Binds to A & B receptors
- VERY weak estrogen, 37,000x weaker (Dodd’s)
- Selective Estrogen Receptor Modulator (SERM)
- @ high doses BPA binds to androgen receptor
- Estrogen Related Receptor Gamma (ERR-gamma)
- Nuclear receptor
- Tamoxifen, DES bind here. They deactivate EERG
- BPA binds strongly, estrogen doesn’t
- BPA is 2x stronger than estradiol
- BPA activates EERG, tamoxifen doesn’t work if BPA present
- BPA oxidized. Metabolites are also active.
We are going to take a quick break and when we come back we will
Commercial #2: pre-recorded
And we’re back…
- We’ve got to avoid this stuff. The problem is that it is EVERYWHERE!!!
- Wear gloves if touching receipts or other thermal paper
- High-quality water filters
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