Bisphenol A (BPA) - MysteriousToxin Extraordinaire?

Released to the public last week, and making headlines in a Washington DC newspaper, a coalition of researchers, physicians and environmental advocacy/child health groups have written a letter to the FDA demanding answers to questions about BPA and asking for it’s removal from food contact materials. They asked why the European Union’s equivalent to the FDA (EFSA) has decided to lower the allowable exposure levels of bisphenol A to 5000 times lower than the current average daily exposure levels in the U.S. and 100,000 times lower than previously assumed safe by the FDA. 

It is doubtful that the FDA will be able to come up with a satisfactory answer. They have been ignoring the science on BPA for years and even ignored it when faced with overwhelming published scientific evidence for BPA’s reproductive and immune harms. 

Now they have an embarrassing situation. As explained in the recently released comprehensive safety assessment of BPA by the European Food Safety Authority (EFSA) on December 15, 2021, anything above .04 ng per kg body weight is an unacceptably high exposure to BPA in the European Union. The average exposure in the U.S. to children and adults over 2 years old is 200 ng per kg body weight – that’s where the 5000-fold times difference comes from. 

The report issued by EFSA:  “Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs” is an evaluation of all the studies looking at BPA’s effect on metabolic disease (diabetes, cardiometabolic disease), reproductive toxicity, immune effects, neurologic damage, behavioral problems, cancer, liver, kidney and endocrine effects. Although EFSA did not find clear evidence of harm for all human systems they did find clear evidence for neurotoxicity, reproductive toxicity in males and females and immunotoxicity, especially for the effect on Th17 cell dysregulation which is correlated with allergies, asthma and autoimmunity.

EFSA Expert Panel’s safety assessment established a new tolerable daily intake for BPA and identified the immune system as the “most sensitive health outcome category” meaning that the immunotoxic effects of BPA outweighed even reproductive toxicity.

Studies have demonstrated widespread daily exposure to BPA in more than 90% of the European and US populations at concentrations above .04 ng/kg. BPA has recently been classified as a reproductive toxicant and a substance of very high concern by the European Chemicals Agency.

If BPA is the ubiquitous toxicant the CDC claims it to be (found in over 93% of representative samples of the U.S. population) where is this exposure coming from? 

Non-dietary sources (dermal and inhalation) have been proposed to be just as much or more of a problem than dietary sources- skin and lung exposures miss the first pass metabolism that ingested exposures go through. But where are those mysterious skin and lung BPA exposure hiding?

An example of this mystery was  a study done by EPA scientists in 2018 assessing exposure in 50 adults from food, dust, and water. They found out that only 20% of the total urinary excreted BPA came from solid food. Where did the remaining 80% come from? 

If you’re thinking canned soup (a liquid vs a solid food), think again. A prior study looking at the diets of children in daycare showed that solid food had 8 times the BPA content of liquid food. This is surprising as we have been told the opposite, that canned food (coconut milk, soup, canned pasta) is the highest source of BPA in the diet. 

The authors were unable to identify the source of the majority of BPA exposure even though they did evaluate levels in the participant’s home drinking water and house dust. BPA was detected in 38% of the food, 4% of the drinking water, and 99% of all of the participants hard floor surface wipe samples. Were they inhaling the BPA? Did the scientists miss exposure because they neglected to look at BPA in bottled water, personal care products, thermal receipts, or the dust in the workplace? The authors declined to speculate. 

Studies have shown detectable BPA in tableware, thermal receipts, electronic equipment, magazines, paints, adhesives, shampoos, bar soaps, body lotions, sunscreens, nail polishes, and recycled paper towels, napkins, toilet papers, and residential indoor air and workplace dust that could be inhaled. 

Scientists working with the Silent Spring Institute detected BPA in a variety of consumer products including a vinyl shower curtain and pillow protector, dish and laundry detergent, tub and tile cleaner, soaps, lotions, shampoo, conditioner, shaving cream, nail polish, and sunscreen. None of the 213 commercial products assayed in the study that contained BPA listed it as an ingredient.

Although BPA is being replaced with other bisphenol structural analogs, most BPA replacements are very similar in chemistry and effect to BPA. These regrettable substitutes: bisphenol S (BPS, in BPA-free thermal receipt paper and BPA-free cans) and bisphenol F (BPF) also show hormonal activity and are increasingly detected in human urine . Other bisphenol analogues: bisphenol AF (BPAF), bisphenol AP (BPAP), bisphenol Z (BPZ), and bisphenol B (BPB) have also been shown to act as xenoestrogens at very low levels of exposure. That’s the reason for, in this case,  the use of the term “regrettable substitutes.”

How can providers navigate this confusing territory to minimize their families’ and patients’ exposure? The scientists at Silent Spring have given us a potent directive. In the study referenced above they assayed alternative products (personal care products, cleaning products, and others) they termed “alternative” they didn’t find any BPA or antimicrobials (triclosan/triclocarban).

How did they find these alternative products? They simply looked for the absence of the following on the ingredient list:

• Parabens

• Ethanolamines

• 1,4-dichlorobenzene

• Nonionic surfactants

• Fragrances (natural fragrances were OK)

• Triclosan, triclocarban

• Antibacterial

• Stain-resistant

• Vinyl

• Petroleum-based

• Tea tree oil and lavender (these products do not necessarily contain BPA but were excluded as they may act as endocrine disruptors)

This is a simple list. Easily done as the Silent Spring researchers were able to find 43 alternative products as a national chain store that specialized in “natural food.” Of course there is still reason to avoid canned food, bottled water, and thermal receipts. 

But more importantly we may need to adopt the European Union guidance and do away with bisphenol A all together. That would be a start.