How some chemicals can disrupt our hormones

We recently caught up with geneticist Dr Michael Antoniou to find out more about his research into the cancer-causing potential of certain chemicals found in the everyday products we use. And how they can impact our health and may increase our risk of breast cancer.

Q. Your current Breast Cancer UK-funded research project looks into the cancer-causing potential of bisphenols in breast tissue. For people who are not familiar with the scientific names used for chemicals, please can you tell us what Bisphenols are and how they are used?

A. Bisphenols are a family of substances that are used in the manufacture of certain types of plastics used to make packaging for food and drink, the most common being BPA. Bisphenols are collectively known as plasticisers.

Q. Why should we be concerned about them, and how are they linked to breast cancer?

A. Structurally, bisphenols resemble the hormone oestrogen, which is found mainly in women and is needed for normal body function. As bisphenols are structurally similar to oestrogen, it has been found that they can mimic its effects; that is, bisphenols can behave like oestrogen and can affect the functioning of the body in a similar way to the natural hormone.

Importantly, many breast cancers are hormone dependent; that is, they need oestrogen in order to grow. Since bisphenols can behave like oestrogen, this means that they can also potentially stimulate the growth of hormone dependent breast cancers.

Q. Can you tell us what you hope to achieve with this research project?

A. Because of concerns about the safety of BPA, plastics manufacturers have begun to replace it with other bisphenols claiming that these substitutes are safer. We are trying to find out if this will be the case. Previous BCUK-funded research showed that 6 BPA substitutes used in plastics manufacture and often found in our bodies can mimic the actions of oestrogen. Indeed, we found that 3 of the BPA substitutes were far more potent at simulating the effects of oestrogen than BPA itself.

The results called into question the claims that the BPA substitutes are safer as, in principle, they could be even more potent. Although research has highlighted the potential for bisphenols to stimulate the growth of pre-existing hormone-dependent breast cancer. What is not clear is if this family of chemicals can give rise to breast cancer in the first place. Our latest BCUK-funded project will be testing to see if mixtures of bisphenols we have worked with before can disrupt the growth of normal breast cancer cells in a manner that would be indicative that they could progress to cancer.

We are working in collaboration with Dr Elisabete Silva at Brunel University London. Dr Silva has already shown that BPA on its own can cause severe disruption to normal breast cancer cell growth, which could lead to a fully blown cancerous state. It is, therefore, possible that a low-dose mixture of bisphenols will be even more capable of disrupting normal breast cancer cell growth with potentially devastating outcomes if this was to happen in people and especially women.

Q. Bisphenols are one of several chemicals which have been classed as hormone disrupting chemicals (sometimes referred to as HDCs or EDCs). For people new to this area of science, please can you tell us what these are and what effect they have on our health?

A. Hormones are natural substances in our bodies. The balanced functioning of hormone systems is vital to our health. HDCs disrupt the normal functioning of one or more hormones by either blocking their activity or mimicking (boosting) their effects.

Imbalances in hormone function caused by HDCs can lead to many serious health problems, both physical and behavioural in nature. HDCs begin to exert their effects at the time when the foetus is forming in the mother’s womb, with problems spilling over into later life. Among the illnesses that can arise from HDCs are birth defects, neurological development problems, obesity, diabetes, hormone-dependent cancers, autoimmune disease, infertility, heart disease and ADHD.

As hormones are essential for normal body function, we should not be surprised to find that anything that interferes with their activity can lead to a large array of serious diseases. As a result, it is estimated that illnesses that are either directly caused or aggravated by HDCs cost health services hundreds of billions of euros in Europe (including the UK) and hundreds of billions of dollars in the USA each year!

Q. How do we encounter HDCs, especially bisphenols, in our everyday lives?

A. The list of HDCs is huge, growing all the time, and we encounter them on virtually a daily basis both at home and in the environment. Many types of chemicals (pesticides) used in agriculture are HDCs and can be found in food. Within the home, flame retardants applied to furniture are also HDCs. There is evidence that some additives to cosmetics, such as parabens and phthalates, are also HDCs. Bisphenol plasticisers make clear plastic bottles for water, soft and alcoholic drinks—and the plastic that lines food and drink cans and as a coating of thermal receipt papers.

Q. How do HDCs increase our risk of breast cancer?

A. HDCs increase the risk of breast cancer in two ways. First, they can contribute to breast cancer formation. Second, they can promote the growth of breast cancer, which has been caused by some other mechanism. HDCs exert these effects by changing the patterns of gene function from a healthy balanced state to an imbalanced state where normal cell growth is replaced with growth that is out of control.

Q. Should we be concerned about our daily exposure to HDCs?

A. Yes.  The wide range of illnesses arising from long-term, daily ingestion of HDCs can affect both sexes equally in similar and different ways.

Q. What would you recommend we do to reduce our exposure?

A. We can all reduce our daily exposure to HDCs in several ways. I list some of the easier lifestyle changes to reduce HDC exposure below.

1. Avoid drinks in plastic bottles or cans. Buy drinks in glass bottles. If you buy a drink in a plastic bottle, never reuse it but deposit it in a recycling bin. This will minimise the ingestion of bisphenol and other HDC plasticisers.
2. Reusable “BPA-free” and BPA/BPS-free” plastic drinks bottles are available, which is a step in the right direction. However, these may still contain other bisphenols that we have found are more potent oestrogen mimics than either BPA or BPS! Thus, best to prefer glass or metal reusable bottles if practical.
3. Avoid buying food in plastic containers and cans as much as possible. Glass jars are good. Buying loose, unpackaged, unprocessed whole foods are even better.
4. Eat organic whole foods of all types as much as possible, as much as you can afford. This will minimize the ingestion of HDC pesticides.
5. Avoid using pesticides in your garden. This avoids exposure to HDC pesticides, which can be breathed in or absorbed through the skin and consumed from your home-grown fruit and vegetables!
6. Check the ingredients of cosmetics; choose those that do not contain parabens or phthalates. Paraben-free and phthalate-free is now a selling point for many manufacturers, and thus such products are easy to find.
7. Avoid receipts at shop checkouts and cash point dispensers.
8. Use plant-based household cleaners. Not only are these unlikely to contain HDCs, but they are also readily biodegradable and thus better for the environment.

For more information on reducing your risk, visit our reduce your risk section. See Our Research section for more information on our current research projects.