Bisphenol A: What is it, its health effects and should we avoid it?

Picture this: you just finished a delicious meal, and in a fight against food waste, you are eager to store your leftovers in a convenient plastic container. Most plastics these days are labelled ’BPA-free’; but what exactly does this mean and why does it matter? This article explores what BPA is, how we come in contact with it, what health risks it entails, and whether we should avoid it.

What is bisphenol-A and where is it found?

Bisphenol A, often abbreviated as ‘BPA’, is a synthetic organic chemical used to make clear, strong, and lightweight plastics known as polycarbonates. These polycarbonate plastics are very common – they are used in reusable water bottles, baby bottles, plates, cups, and containers for storing food. BPA is also used for creating epoxy resins that are used to line the inside of food and drink cans. Other than food packaging and containers, BPA is used for manufacturing electronics, construction materials, and medical devices among other things.

How do we come in contact with bisphenol-A?

We come into contact with bisphenol-A through various routes. Firstly, BPA can migrate from containers and materials that come into contact with food such as plastic bottles and the lining of food cans. When these containers are heated, reused excessively, or exposed to acidic or basic substances, BPA transfer to food increases.¹ Acidic substances in food typically include citrus fruits, tomatoes, and vinegar-based products, which have a low pH and can contribute to breaking down the chemical bonds in plastics, allowing the release of BPA. On the other hand, basic (or alkaline) substances in food might include baking soda or certain dairy products, which have a higher pH and can also affect the integrity of plastic containers. BPA migration is especially a cause for concern in high-fat foods and when the packaging directly touches the food for a long time or is exposed to higher temperatures.¹

Secondly, BPA is considered an omnipresent environmental contaminant, found in air, soil, and water due to its widespread use.¹ Environmental exposure to BPA results from contamination of the atmosphere, aquatic environments, and soil, largely due to industrial use and recycling processes.¹ BPA can last in the environment for a while, but microorganisms present in water bodies as well as sunlight help decompose it over time.¹ Occupational exposure to BPA occurs primarily among workers involved in its production.

Is bisphenol-A harmful and why?

BPA is considered a hazardous substance in the European Union because it can harm fertility, cause eye damage, allergic skin reactions, and irritation to the airways.² It's also known to disrupt hormones, which can affect reproductive function, cognitive abilities, and metabolism.² In 2023, the European Food Safety Authority (EFSA) updated its safety guidelines for BPA after finding evidence that it affects the immune system . Studies in mice showed that even at very low doses, BPA can impact cells important for immune responses, potentially leading to conditions like autoimmune diseases and lung inflammation.²

Does bisphenol-A cause cancer?

Exposure to BPA is linked to a higher risk of various cancers, including breast, uterus, ovarian, prostate, and testicular cancer.^3,4,5 The estrogenic activity of BPA is thought to be the main reason behind these cancer risks.³ BPA can affect responses at the cell level by interacting with oestrogen receptors, even at low concentrations. It can also stimulate cell division and growth in breast cancer through certain signalling pathways. Additionally, BPA can cause changes that affect the regulation of gene expression. Gene expression is the process by which the information encoded in a gene is turned into a function. The changes that BPA can affect DNA stability and alter the function of certain cells, potentially leading to cancer.⁵ Furthermore, exposure to BPA may disrupt immune function, promoting the growth and spread of cancer cells.1 However, the precise effects and mechanisms of BPA on cancer development in humans are still not fully understood and need additional research.¹

Takeaway

It is important to remember that several variables can influence the overall health risk for an individual. Cancer is a complex disease with many different factors at play, including genetics, lifestyle, and environmental factors and develops over many years.

Should we avoid bisphenol-A?

Yes, exposure to bisphenol-A must be avoided due to the negative health impacts it is associated with. However, due to the widespread presence of the chemical, individual caution alone cannot guarantee public safety. Since migration via food contact materials is the most common pathway for exposure to BPA, regulations have been created to minimise its occurrence in these materials.

BPA is currently allowed for use in plastic food contact materials in the EU, but with restrictions. These include a specific migration limit of 0.05 mg/kg.⁶ There is also a ban on using BPA in food contact materials specifically for infants and young children.⁶ These regulations have been in effect since September 2018, except for the ban on BPA in polycarbonate infant feeding bottles, which has been in effect since 2011.

In 2023, EFSA established a new tolerable daily intake (TDI) for BPA at 0.2 ng/kg bodyweight, expressing concern over health risks from dietary exposure to BPA .⁶ A TDI is an estimate of the amount of a substance in food or drinking water which is not added deliberately, and which can be consumed over a lifetime without presenting an appreciable risk to health. Considering the new, much lower TDI, the Commission is proposing to ban the intentional use of BPA in food contact materials.⁶ The draft measure aims to remove BPA from the list of authorised monomers and propose its ban in the manufacture of all other synthetic organic materials where it may be used.⁶

Summary

Bisphenol-A (BPA) is a widely used synthetic chemical found in polycarbonate plastics and epoxy resins, commonly used in food packaging, containers, and canned foods, as well as electronics, construction materials, and medical devices. Exposure to BPA occurs through contact with these materials and through environmental contamination. BPA is considered hazardous due to its potential to affect the immune system, harm fertility, disrupt hormones, and increase the risk of various cancers, among other health concerns. Regulatory measures have been implemented to limit BPA exposure, including specific migration limits and bans on its use in certain products for infants and young children. In 2023, the European Food Safety Authority (EFSA) established a new safety guideline, prompting proposals to further restrict BPA use in food contact materials.

References

1. Almeida, S., Raposo, A., Almeida‐González, M., & Carrascosa, C. (2018). Bisphenol A: Food exposure and impact on human health. Comprehensive reviews in food science and food safety, 17(6), 1503-1517.
2. European Environment Agency (2023). Human exposure to Bisphenol A in Europe.
3. Song, H., Zhang, T., Yang, P., Li, M., Yang, Y., Wang, Y., ... & Zhang, K. (2015). Low doses of bisphenol A stimulate the proliferation of breast cancer cells via ERK1/2/ERRγ signals. Toxicology in vitro, 30(1), 521-528.
4. Bromer, J. G., Zhou, Y., Taylor, M. B., Doherty, L., & Taylor, H. S. (2010). Bisphenol-A exposure in utero leads to epigenetic alterations in the developmental programming of uterine estrogen response. The FASEB Journal, 24(7), 2273.
5. Rezg, R., El-Fazaa, S., Gharbi, N., & Mornagui, B. (2014). Bisphenol A and human chronic diseases: current evidences, possible mechanisms, and future perspectives. Environment international, 64, 83-90.
6. European Commission’s Directorate-General for Health and Food Safety (2023). Questions and answers concerning the risk management approach for bisphenol A and other bisphenols in food contact materials.