Red hot findings indicate new dangers with bisphenol A

Hormon disturbing chemicals (Photo: Sooz)

Hormon disturbing chemicals can be dangerous (Photo: Sooz).

Endocrine disruptors interfere with our bodies’ finely tuned hormonal regulation systems. Unfortunately, human exposure to endocrine disruptors, and particularly to bisphenol A commonly found in food packaging materials, is omnipresent in our daily lives. The potential risks to consumer health of such chemical contaminants have been the subject of many contradictory reports with science divided over how to handle the findings. Now there seems to be a link between bisphenol A exposure and food intolerance. More than 20% of the global population suffer from food allergy or intolerance making this an important issue.

Scientific controversy

The French are hellbent on proving that bisphenol A is a dangerous chemical that should not even come close to food of any sort. And they might be right. In the USA it is the opposite situation with federal agencies protecting the use of bisphenol A in food applications at any cost. They cannot both be right though. The arbiter is sitting on the fence. This is the European Food Safety Authority that recently completed a new draft assessment of bisphenol A but decided to consult extensively with external stakeholders before making a final decision. It is not going to be easy.

To start in France,  the French Agency for Food, Environmental and Occupational Health and Safety (ANSES) published an opinion on bisphenol A in April 2013 which recommended limiting exposure to this substance and lowering the toxicological thresholds on which risk evaluations were based. This resulted in the French government deciding to ban the use of bisphenol A in all food packaging from 2015. And new research findings are accumulating showing new dangers.

New scientific results published

Using female rats exposed to bisphenol A at low doses during pregnancy and early suckling, scientists at INRA’s Joint Research Unit for Food Toxicology in Toulouse demonstrated that it affected development of the immune system in the off-spring of the exposed rats and predisposed their progeny to food intolerance in adulthood. The scientists tested different doses (0, 0.5, 5 and 50 μg/kg body weight per day) and demonstrated a non-linear relationship between the bisphenol A doses and the undesirable effects observed. In particular, the most marked disturbances were observed at a dose of 5 μg/kg body weight per day. This is of course confusing but in line with the low dose hypothesis suggesting that there can be different reactions at different dose levels. At the low-dose level the scientists found that when challenged with ovalbumin, an egg white protein not previously included in their diet, an immune reaction was seen directed against ovalbumin which induced colonic inflammation that testified to a food intolerance. However, rats descending from the control group developed a food tolerance to ovalbumin, which resulted in a lack of immune response.

This is the same dose of 5 µg/kg body weight per day that is proposed by EFSA to be safe. The new findings highlight the problem of determining a safe and tolerable dose for bisphenol A. EFSA is still to make up their mind but has so far used the expression “as likely as not” for many negative findings to indicate an uncertainty around the real health impact of current human exposure levels.

Laboratory findings questioned

Laboratory findings questioned because of contamination.

Americans have been more gung ho about the safety of bisphenol A. To be fair there is an ambitious ongoing U.S. research project known as “CLARITY-BPA” into the safety of bisphenol A funded to the tune of US$32 million. But scientists from the National Center for Toxicological Research in Arkansas preempted this research by publishing interim findings in Oxford Journals’ Toxicological Sciences claiming that only very high doses of bisphenol A are dangerous, and that the “low levels” in common circulation through plastic bottles, thermal paper receipts, tin can linings and other sources are not a threat. These findings have since been heavily criticised because of bisphenol A contamination also of the control group.

Is there a safe level?

So what to believe? It seems pretty clear that not even 5 µg/kg body weight per day is a safe level. But actual exposure might be much less than this according to EFSA’s new exposure calculations as long as you don’t live exclusively on canned food. We have to wait until the end of 2014 until we can get access to EFSA’s conclusions. Agony for us and for the scientists grappling with the final opinion.

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