Bisphenol A (BPA) is a synthetic chemical composed of two phenol rings joined together by a carbon atom. It is manufactured in huge quantities (3 billion kg/year) for use in the production of polycarbonate plastics (e.g. dummies, inside lining of tinned foods and beverages), as well as other industrial applications, such as the manufacture of PVC piping or flooring.
BPA is leached fairly easily from these plastic products when moistened (especially with hot water). It is also leached in the presence of detergents, acids, and greasy substances — including food. Although BPA is excreted fairly rapidly from the body, anyone living in a developed country consumes this substance unknowingly, virtually every day. BPA is therefore present in our body tissues in significant amounts, more so in women than men and more so in children than in adults. BPA is perhaps not overtly harmful in the short term, but its chemical structure does suggest that it could affect our health in the medium and long term.
There is an abundance of scientific literature describing the effects of BPA in animal “models” but Antidote does not consider these studies to be relevant to human health, since no species can reliably substitute another when evaluating chemical toxicity.
There are three relevant approaches:
- the study of human biological material;
- epidemiological (human population) studies;
- molecular studies, where the structure of test substances is compared with those of known biological activity in humans.
As an early screening test, the science of toxicogenomics is ideally suited to the task at hand. Results can be obtained quickly, cost-effectively and are relevant to the species in question — humans.
Several such studies are already in the public domain. One such study — commissioned by Antidote Europe — shows that BPA and its metabolites (breakdown products) significantly interfere with the ability of the cell to guard against oxidative stress, uncontrolled cell growth (cancer), excessive hormonal stimulation and incorrect protein folding. This type of cell damage increases the likelihood of so-called “conformational” diseases, including Parkinson’s disease, Alzheimer’s, and adult onset (type 2) diabetes. Other effects on the body include hormonal imbalances during sexual development and a decrease in male fertility. The data from our study has been duly logged in an international database.
Additional studies with toxicogenomics and human cells, have shown that the oestrogenic effect of BPA is at least as powerful as the naturally occurring hormone, 17beta-estradiol, but that BPA and other estrogen-mimicking chemicals tend to amplify normal gene function associated with this hormone. Even tiny concentrations — which may have undetectable activity — are therefore sufficient to produce significant hormonal effects (leading to breast or prostate cancer) as well as genital malformations (1). These effects have been confirmed in human population studies (2-10).
It is an established fact that chemicals resembling each other structurally will have similar biological properties (QSAR concept). The compound diethyl stilbestrol (DES)also has two phenol rings, joined by two carbon atoms (instead of just one in the case ofBPA). For a period of 30 years, DES was prescribed to pregnant women in France, as an aid to prevent abortion (but for which it was ineffective). A total of 200 000 women were exposed to this drug. It would take science 30 years to discover that this drug was teratogenic, producing serious birth defects (chiefly cervical cancer) in the daughters — and even the grand daughters — of these women. Since BPA and DES closely resemble each other structurally, it is very likely that they will have similar biological properties. The catastrophic effects of DES are documented in medical history for all to see. There is now the grim possibility that we will face a BPA “time bomb” sometime in the future. Unlike DES, it will be a much greater challenge to removeBPA from our environment. Equally disturbing is the fact that not only pregnant women will be affected, but the entire population, especially young children. This represents an existentialist threat to the survival of the human species, where fertility in both sexes will be affected, in addition to causing an increase in diseases such as cancer, neurodegenerative conditions, diabetes, and many others.
According to ‘experts’ BPA poses only a “mild” or “insignificant” risk to humans, despite the fact that this chemical continues to build up in our bodies. These same experts also tell us that pregnant women and their unborn foetuses have nothing to fear because “pregnant women rapidly metabolise and excrete this chemical”. Surely these experts must know that the speed at which a substance is broken down and passed out of the body has nothing to do with its biological activity while it is inside the body? This is a basic principle of pharmacokinetics (drug action).
France should respect the health of its citizens by following the example of Canada in 2008, and withdraw BPA from the market to protect the nation’s health and future prosperity.
References:
- “Convergent transcription profiles induced by endogenous estrogen and distinct xenoestrogens in breast cancer cells”, Buterin T., Koch C. &H Naegeli, Carcinogenesis 2006, 27 : 1567-78.
- “Association of urinary Bisphenol A concentration with medical disorders and laboratory abnormalities in adults”. Lang IA, Galloway TS, Scarlett A et Als JAMA, 2008;300:1303-1310.
- “Urinary concentrations of bisphenol A and 4-nonylphenol in a human reference population.” Calafat AM, Kuklenyik Z, Reidy JA, et al. Environ Health Perspect 2005 ; 113 : 391-5.
- “Positive relationship between androgen and the endocrine disruptor, bisphenol A, in normal women and women with ovarian dysfunction”.Takeuchi T, Tsutsumi O, Ikezuki Y, Takai Y, Taketani Y, Endocr J, 2004;51:165-169.
- “Bisphenol-A disruption of the endocrine pancreas and blood glucose homeostasis” Ropero AB, Alonso-Magdalena P, Garcia-Garcia E, Ripoll C, Fuentes E, Nadal A, Int J Androl, 2008;31(2):194-200.
- “Thyroid hormone action is disrupted by bisphenol A as an antagonist”, Moriyama K, Tagami T, Akamizu T et als. J Clin Endocrinol Metab, 2002;87:5185-5190.
- “Bisphenol A is released from polycarbonate drinking bottles and mimics the neurotoxic actions of estrogen in developing cerebellar neurons”. Le HH, Carlson EM, Chua JP, Belcher SM. Toxicol Lett. 2008 Jan 30;176(2):149-56.
- “Parental bisphenol A accumulation in the human maternal-fetal-placental unit”, Schönfelder G., Wittfoh W., Hopp H., Talsness CE., Paul M. &Chahoud I. Env. Health Perspect 2002; 110: A703-7.
- “Migration of bisphenol A from polycarbonate baby and water bottlesinto water under sever conditions” Coa X.L. & Corriveau J. J. Agric Food Chem 2008; 56: 6378-81.
- “Exposure to Bisphenol A and Other Phenols in Neonatal Intensive Care Unit Premature Infants” Calafat AM & al. 2009 Env. Health Perspect. 117: 639-44.