Chemical Mixtures: A Recipe for Breast Cancer

Article Author: Amanda Thompson, Biology Major, Class of 2023, POB Science Coordinator

What does an egg taste like? Well, that depends on what it is being mixed with. Are we scrambling it with salt and pepper? How about making an omelet with cheese and veggies? What if we were to mix flour, sugar and butter in with the egg? That would give us a sugar cookie! Add in a little bit of brown sugar and chocolate chips, and all of a sudden your dough will turn a light brown color and behold, your favorite cookie has a much better flavor. Our taste buds can be impacted in so many different ways by one egg when it is mixed with different ingredients. This same concept applies to how our body is impacted by the different mixtures and reactions of chemicals of concern that we expose ourselves to every day. 

Most previous research has focused on the “individual exposure conditions” of chemicals, looking at how our body responds to one chemical on its own. Through this research, we have been able to find a number of chemicals of concern, most significantly endocrine-disrupting chemicals (EDCs). As we know, these EDCs can disrupt natural endocrine system regulation by mimicking hormones, leading to various health concerns including breast cancer. Some of these chemical classes include bisphenols, parabens, phthalates, and polybrominated diphenyl ethers. 

While it is extremely important to have knowledge on individual toxicity of chemicals, there has been a lack of conversation on the weight that these chemicals may hold when they co-occur in products. Let’s relook at the cookie example. The egg, flour, sugar and butter are all their own separate items. We could eat each individually and our body will digest them independently, but all together, these ingredients can make something that our body responds to differently. Chemicals can work the same way. Individually, they may have an effect on our body, but their collaboration with one another could have its own unique impact. The problem is, there is not enough research to tell us which co-occurence of chemicals may be the most detrimental.

A brand new 2022 research paper by Lauren E. Koval gave us more insight on the concept of mixtures by “[characterizing] combinations of chemicals that likely occur in our everyday environment which may be impacting risk of acquiring breast cancer”. Specifically, the study identified 6794 unique chemicals to categorize and analyze. To begin with, each chemical was identified as either breast-cancer chemicals (BC), non-breast cancer chemicals (NBC), or understudied chemicals (UCs). As indicated by their name, BCs have a known association with breast cancer risk, NCs did not have enough of an association with breast cancer risk and UCs lacked the research to establish a breast cancer risk. 

UCs that co-occur with BCs were prioritized as significant chemical mixtures based on their chemical exposure source, structural similarities to BCs, and physicochemical similarities to BCs. Results found there to be various understudied chemicals that share the same chemical property similarities with known BCs; this could signify a similarity in the carcinogenic effect that the chemicals have on our body. On top of this, using this prioritization, Koval identified “50 top-ranking chemicals in 5 clusters of environmental relevance” that require further research and testing.  

This research not only adds to the overdue conversation about mixtures of chemicals and their joint effects on our bodies, but also identifies many chemicals that need much more attention than they are receiving. While this can be overwhelming, know that there are steps that you can take to avoid the chemicals that we know put us at risk! If you consider the Web of Causality, we know there are threads to snip away at to lessen our exposures. The first step you can take is  to cut out synthetic pesticides by choosing USDA certified organic products. From personal care to the clothes we wear, more and more information is coming out about safer alternatives to choose. You can find more resources and digestible tips on our website and social media! 


Koval, L.E., Dionisio, K.L., Friedman, K.P. et al. Environmental mixtures and breast cancer: identifying co-exposure patterns between understudied vs breast cancer-associated chemicals using chemical inventory informatics. J Expo Sci Environ Epidemiol (2022).



The information provided herein is the author’s opinion. Our authors are not scientists. We are not providing medical advice, but simply sharing publicly available information. When we reference data and databases, we do so with the caveat that most are only as good as the data they are based on. While POB strives to make the information as timely and accurate as possible, we make no claims, promises, or guarantees about the completeness, or adequacy of the contents of any site that is shared, and expressly disclaims liability for errors and omissions in the contents of these sites. POB goes to great lengths to avoid declaring shared products as “safe” as there is no legal definition of the word “safe” at this time.

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