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What we can’t see can hurt us: Connecting the dots between breast cancer and food

Annually, over 2 million women are affected by breast cancer across the globe.

October 10, 2019

Odds are that someone in your immediate circle is dealing with breast cancer, given that it affects 1 in 8 women in the United States. Simply being a woman is the single largest risk factor in developing breast cancer. Add age to that equation, specifically 50 and above, and the risk increases by 70%.

Studies show possible links between certain chemicals called endocrine disruptors and the onset of breast cancer. We begin collecting these chemical stowaways in utero. As their concentrations increase, they become biochemical tinderboxes that can fuel cancer. The question is still out as to which and how exactly the stockpiled chemicals cause harm.

“Our research suggests that the modern diet is largely responsible for the slow accumulation of these disruptors," said Rolf Halden, professor and director in the Biodesign Center for Environmental Health Engineering at Arizona State University. "After digestion, they enter our blood stream. Because they can combine with lipids and fats, they get lodged into adipose tissue, or fat cells, like those found in mammary glands.” 

Halden and graduate researcher Devin Bowes investigated the link between the endocrine disrupting chemicals found in our diet and the incidence of breast cancer. After poring over scores of published medical and environmental reports, they compiled a review for Current Pathobiology Reports, “Breast Cancer and Dietary Intake of Endocrine Disruptors: A Review of Recent Literature.

How does endocrine disruption lead to breast cancer?

At any given time, some 50 different types of chemical messengers, called hormones, are zooming through our bodies. Hormones busily dart from cell to cell regulating, initiating, inhibiting and balancing our cellular processes. They influence the essence of our gender, affect the beat of our hearts and regulate our reproduction. Hormones are managed and synthesized by a collection of glands called the endocrine system.

Most are unaware of their own endocrine system until it goes awry. Endocrine disruptors are chemical compounds that impede or exaggerate the zip and the zap of hormonal activity. According to the Environmental Protection Agency, they are agents that inhibit or overexpress the “synthesis, secretion, transport, metabolism, binding action, or elimination of natural blood-borne hormones.” Dysfunction of the endocrine system can mutate cells, affect signaling processes and mimic hormones.

Devin Bowes

Devin Bowes, a graduate student in the Biodesign Center for Environmental Health Engineering, connects the relationship between food and breast cancer.

“This really throws a monkey wrench into critical puberty stages like breast development where the endocrine system is crucial to normal cell development and maturation,” Bowes said. “It suggests that even though an individual’s breast cancer shows up at age 60 — the process could have been building up since age 16 or so.”

As you may imagine, disruption compromises our homeostasis (balance), which can lead to improper growth, developmental irregularities, heart abnormalities, thyroid disorders, metabolic issues and cancer, amongst other maladies. Cancer has learned how to tap into the power of endocrine disruptors and use them to accelerate its growth and tumor formation. 

Here, there, everywhere: Avoiding endocrine disruption

Endocrine disrupting chemicals can be found everywhere.

“In our review, we examine estrogen-mimicking endocrine disruptors because certain types of breast cancer are largely driven by fluctuations in estrogen levels,” Halden said.

The research team point out several breast cancer-related hormonal disruption sources that can be delivered through our diet, like insecticides, herbicides and plastics. They also looked at parabens and phytoestrogens that are naturally found in fruits and vegetables.

Insecticides and herbicides, like DDT (dichlorodiphenyltrichloroethane) and atrazine, are potent toxins. “There was an 80% overlap between these chemicals and breast cancer as reported by a 10-year study involving over 2,000 patients,” Bowes said. “The obvious answer is to reduce usage, but historically this has been a real challenge.”

In 1962, Rachel Carson traced dispersed DDT from the soil to the animals and right up the food chain — to our dinner plates. She wrote a detailed account of her findings in her book “Silent Spring.” The chemical industry refuted her conclusions and campaigned against the book. However, DDT wiped out whole ecosystems. The evidence was indisputable. Concern sparked an environmental movement and led to the establishment of the Environmental Protection Agency in 1970. The Environmental Protection Agency halted the use of DDT in the U.S, but by 1972 the damage had already taken hold. We know now that women are four times more likely to develop breast cancer before the age of 50 if they have been exposed to DDT.

Atrazine remains one of the most widely used herbicides for crops in the U.S., whereas it has been banned in the European Union and many other countries for decades. It concentrates in soil and groundwater near agricultural areas. It is extremely detrimental to developing fetuses and young children, with even small amounts of exposure being associated with an increase in cancer risk.

Rolf Halden

Rolf Halden, professor and director in the Biodesign Center for Environmental Engineering, highlights the presence of endocrine disruption in our diets.

“Opportunities to limit exposure to potentially harmful pesticides includes washing fruits and vegetables prior to consumption and to seek out organically grown agricultural products where available and if affordable,” Halden said.

Plastics and plasticizers such as BPA and phthalates leach into our food through food processing, containers, canned goods, plastic utensils and plastic wraps. Not surprisingly, biomonitoring of individuals has demonstrated population-wide exposure.

The Environmental Protection Agency considers the use of BPA in polycarbonates and resins as a public health concern and moderately regulates it. The industry quickly switched to bisphenol S (BPS), a sister compound that, not surprisingly, has similar negative effects.

Plastics are pervasive in today’s food market. Phthalates are a broad class of plasticizers used in industry, and they are everywhere. There is very little regulation of them and the use of phthalates carries no requirement to alert consumers about its use. They are of concern due to their ubiquitous presence in our everyday lives. The accumulation of phthalates is associated with endocrine toxicity.

“One way to minimize exposure to plastics in our food is to remove the packaging prior to heating. This decreases the migration of chemicals of concern into food,” Bowes said.

You may be surprised to find that some endocrine disrupting chemicals come from natural sources, such as isoflavones and parabens.

Bowes explained that “phytoestrogens, like isoflavones in soy, and parabens naturally found in fruits and vegetables were on our radar because they can be involved with altering hormone levels. These exposures are of public health concern only when occurring in excess.”

“For example, women with a family history of breast cancer may want to limit intake of naturally occurring estrogens,” Halden said.  

What can we do to be healthier?

It is safe to say that a balanced diet and exercise contribute to an overall healthier life style. The researchers’ review article points out that healthy choices also need to include actively reducing chemical toxins that are present in our diets. 

“Not only do consumers need to be more cautious about what they are eating and purchasing, but industry’s approach to packaging may need to be reevaluated to enhance public safety. Limiting the use of plastics is a good idea for both our health and global sustainability in general,” Bowes said. “This review should serve as a reminder to both consumers and industry that what we eat has a direct impact on our health." 

Although the levels may be low, constant exposure to endocrine disrupting chemicals can trigger chronic health issues. Animal studies demonstrated that even low levels of exposure to endocrine disruptors during critical developmental periods can cause significant damage, with the development of cancer being one documented outcome.

“The takeaway here is awareness,” Halden said. “We need to be more aware of what is going into our bodies. We have the power to control what we eat. By choosing fresh vegetables and fruits and avoiding processed foods that are stored in plastic, we can protect both our health and the ecosystem services humanity relies on for survival.” 

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