Going plastic free is all the rage right now – as it should be! Many people are making the switch to more sustainable packaging to do their bit for the environment. While the health of the planet will have an impact on the health of humans, it is also important to understand the direct impact that plastics can have on human health.

Plastics, hormones and reproduction

Chemicals found in plastics, most notably bisphenol-A (BPA), are xenohormones (an external compound that mimics human hormones), and have been recognised as an environmental contaminant that significantly disrupts the human endocrine (hormone) system by altering the production, release, transport, metabolism, binding, action or elimination of human hormones that program or maintain normal growth and development

Evidence shows that BPA interferes with the endocrine function of the hypothalamic-pituitary axis (the system that regulates our hormones), which negatively affects puberty, ovulation and fertility. It is due to BPA’s chemical structure being similar to that of oestrogen that leads to an accumulation of the xenohormone in reproductive organs, altering their effects (Huo et al 2015).

Studies have indicated that exposure to BPA can have adverse effects on ovarian age, affecting women’s fertility (Souter et al 2013). BPA has also been linked to lowered sperm count, with research indicating that slightly infertile men have significantly higher BPA sperm and blood concentrations compared to healthy men (Vitku et al 2015).

Plastics and impacts on children

A 2017 review by Braun found evidence that endocrine disrupting chemicals such as phthalates, BPA, perfluoroalkyl substances (PFAS) and triclosan are positively correlated with the prevalence of obesity in children. In-utero (foetal development), infants and children might have enhanced sensitivity to environmental stressors such as the chemicals in plastics due to their rapid development and increased exposure, leading to long term adverse health effects such as obesity. The review also found that prenatal exposure to plastics are associated with reduced cognitive abilities, attention-deficit hyperactivity disorder (ADHD) symptoms and increased autism risk due to their ability to disrupt healthy thyroid function in the mother.

Plastics and cancer

Determining whether there is a link between cancer and plastics is still under scrutiny in the scientific community. A 2016 review by Seachrist et al, found that there is an increased risk of oestrogen related cancers such as breast and prostate from BPA exposure below ‘safe’ levels in rats. The study also found that early exposure to BPA, as well as prenatal exposure increases the risk of cancer, particularly breast cancer, later in life. This is again due to BPAs hormonal disrupting effects.

Extrapolating whether this will apply to humans is hard to do as it is unethical to expose humans to a substance that is presumed to do harm, as well as the fact that everyone on the planet has been exposed to plastics, so finding a control group is also difficult. However, given the strong amount of evidence based on animal studies with similar hormones and receptors to humans, many experts agree that there is enough evidence to conclude that BPA is implicated, with increased risk of breast and prostate cancer.

Aside from a link to cancer, research also suggests that BPA can promote a range of other health issues, including heart disease, diabetes and thyroid function.

So does this mean that all we need to do is avoid BPA by buying BPA-free plastic? The short answer is no. Research suggests that over 90% of over 500 plastic products marketed as BPA-free released chemicals that, in some cases, have greater oestrogenic activity than the BPA-containing plastics (Yang et al, 2011). Another assessment survey showed that many BPA free replacement products still leached chemicals with the significant levels of oestrogenic activity, as did BPA-containing counterparts they were meant to replace (Bittner et al, 2014). Further, most studies done on plastic and their health effects look at each chemical in isolation which does not take into consideration their cumulative health effects.

What can we do about this?

• It’s important to support our detoxification pathways to eliminate chemicals in the body, we can do this by ensuring adequate fibre and water in the diet to promote regular bowel movements, including cruciferous vegetables in your diet every day and dry skin brushing (seeing a naturopath or nutritionist can help you navigate this). This Lamb Curry with Cauliflower recipe is packed with ingredients that support healthy detoxification.
• Don’t heat plastic in the oven or microwave
• Use glass or stainless steel water bottles and glass food containers instead of plastic
• Use reusable fabric shopping bags instead of plastic
• Use paper instead of plastic where possible

References:

Braun, JM 2017, ‘Early-life exposure to EDCs: role in childhood obesity and neurodevelopment’, Nature Reviews Endocrinology, vol. 13, pp. 161-173.

Bittner, G, Yang, C & Stoner, M 2014, ‘Estrogenic  chemicals often leach from BPA-free plastic products that are replacements for BPA-containing polycarbonate products’, Environmental Health, vol.13, no.41.

Huo, X, Chen, D, He, Y, Zhu, W, Zhou, W & Zhang, J 2015, ‘Bisphenol-A and Female Infertility: A Possible Role of Gene-Environment Interactions’, International Journal of Environmental Research, vol. 12, pp. 11101-11116.

Seachrist DD, Bonk KW, Ho SM, Prins GS, Soto AM, Keri RA  2016, ‘A review of the carcinogenic potential of bisphenol A’, Reproductive Toxicology, vol. 59, pp. 167-82.

Souter, I, Smith, KW, Dimitriadis, I, Ehrlich, S et al 2013, ‘The association of bisphenol-A urinary concentrations with antral follicle counts and other measures of ovarian reserve in women undergoing infertility treatments’, Reproductive Toxicology, vol. 42, pp. 224-231.

Vitku J, Sosvorova L, Chlupacova T, Hampl R, Hill M, Sobotka V, Heracek J, Bicikova M, Starka L 2015, ‘Differences in bisphenol A and estrogen levels in the plasma and seminal plasma of men with different degrees of infertility’, Physiological Research, vol. 64, pp.303-11.

Yang, C, Yanuger, S, Jordan, C, Klein, D & Bittner, G 2011 ‘Most plastic products release estrogenic chemicals: a potential health problem that can be solved’, Environmental Health Perspectives, vol, 119, pp. 989-996.