We have covered bisphenol A, called BPA for short, several times before. In case you need to be reminded, it is a chemical widely used in plastic water bottles, metal food cans, and receipt paper. A large number of scientific publications have questioned the safety of BPA. High doses were found to influence the hormonal balance by acting as an endocrine disruptor with oestrogenic effects already in the 1930’s.
Debate over the toxicity of BPA is on-going with findings of potential low-dose effects particularly worrying. The European Food Safety Authority (EFSA) has so far refrained from suggesting that BPA should be banned, contrary to the opinion of government scientists from France and Denmark. At least EFSA lowered the temporary tolerable daily intake (tTDI) by more than 10 times in its latest opinion. And BPA has been removed from baby bottles in many countries.
New bad reports piling up
By setting a temporary TDI, EFSA committed to the re-evaluation of BPA when a two-year study by the U.S. National Toxicology Program becomes available in 2017. But in the meantime results from several other studies have been published.
A report by the Dutch National Institute for Public Health and the Environment (RIVM), critically examined two studies describing pre- and perinatal effects of BPA on the immune system. The report recommended supporting research on alternatives to BPA and advising consumers to reduce their exposure to BPA from food and other sources.
And another recent study equally points to the often neglected prenatal exposure to BPA. A team of U.S. researchers tracked 369 mother-child pairs from the third trimester of pregnancy until the children turned seven years old. They measured BPA levels in the mothers’ urine during pregnancy and then checked the children’s height, weight, waist circumference, and body fat as they aged, also measuring their BPA levels. They adjusted the results for factors that could potentially skew the results, including race and pre-pregnancy obesity among the mothers.
They found that the higher the mothers’ BPA exposure was during pregnancy, the more signs of obesity girls showed at age seven. There was no such association for boys; nor was there any relation between BPA levels in the children’s urine and obesity as they grew.
So it seems that the foetal period is when we’re most vulnerable to BPA and its ability to alter metabolism and the way our bodies generate fat cells. It is not surprising that BPA seems to affect girls differently than boys since as an endocrine-disrupting chemical it mimics or blocks hormones produced by the body. Boys and girls produce different hormones, so hormone-disrupting chemicals might be expected to affect them differently.
And if that’s not enough, experimental laboratory evidence suggests that BPA is a neurodevelopmental toxicant. In further disturbing findings, a longitudinal cohort study confirmed the association between prenatal BPA exposure and child behaviour in preschool-age children, accounting for postnatal BPA and other potential confounders. Among boys, prenatal BPA exposure was positively associated with higher scores on all syndromes and significantly associated with Emotionally Reactive and Aggressive Behaviour. Inverse associations were seen in girls for all syndromes and these associations were significant for Anxious/Depressed and Aggressive Behaviour.
How long to wait?
So it seems pretty clear that BPA can have significant effects at levels of exposure seen in real life.
Do we really have to wait further for some real progress. Authorities seem reluctant to take decisive action despite overwhelming proof of harmful effects. Sure, not all findings point in the same direction and alternatives to BPA might be as bad.
But don’t despair, you can take your own action. To reduce exposure to BPA, the National Institute of Environmental Health Sciences recommends avoiding plastic containers numbers 3 and 7, shifting from canned foods to fresh or frozen foods, and, when possible, choosing glass, porcelain, or stainless steel containers, especially for hot food and liquids.