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Clear Science

• Chemicals Linked to Breast Cancer
  • Plastics
  • Cosmetics
  • Household Products
  • Food
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  • Health Care
• Timing of Exposure
  • Prenatal
  • Childhood
  • Pregnancy
• Vulnerable Populations
  • Genetics
  • Polluted Communities
  • Race and Ethnicity
  • Workers
• Innovative Research
  • BPA in Food Packaging
  • State of the Evidence 2010
  • Pollution in People
  • Breast Cancer Endpoints
  • The Falling Age of Puberty
• Chemicals Glossary

Chemicals in Food

In some ways, our ancestors had it easy. Because they didn't have chemically treated food and chemically enhanced kitchenware, their diets and cooking practices exposed them to fewer toxic hazards.

Today when we eat meat, poultry and dairy, we eat the residue of everything the animal ate, including growth hormones, pesticides and contaminants.

And it's not just the food itself that you have to watch, but the containers they're stored in, which can leach toxic chemicals such as BPA, styrene and vinyl chloride. Not only do they sound unappetizing, they're actually bad for you.

Following are some of the harmful chemicals commonly found in our food and food containers, along with descriptions of what they are, where they're found and why they're bad. And check out our Tips for Prevention section to learn how to avoid them.

Bisphenol A (BPA)

Bisphenol A (BPA) can be found in reusable plastic food containers and the lining of food and beverage cans. Research shows that BPA exposure is linked to breast cancer, and has been shown to interfere with chemotherapy treatment for the disease.

Phthalates

Phthalates can be found in some plastic food containers and are considered endocrine disruptors. Phthalate exposure has been linked to early puberty in girls, a risk factor for later-life breast cancer. Some phthalates also act as weak estrogens in cell culture systems.

Pesticides

Some pesticides and herbicides used on the food we eat have been labeled as human or animal carcinogens and many are also found in water supplies and indoor air and dust. Pesticide exposure is of particular concern for agricultural workers. Studies have shown that some herbicides and pesticides stimulate growth of breast cancer cells or cause mammary cancer in rats.

Zeranol

Zeranol is one of the most widely used chemicals in the U.S. beef industry. It is of special concern since it mimics the hormone estradiol. Scientists recently exposed cancer cells to zeranol-treated beef and the results showed significant increases in cancer growth.

rBGH/rBST

Since its introduction in 1993, bovine growth hormone (rBGH/rBST) has proven controversial because of its potential carcinogenic effects. Several studies have shown an association between dairy consumption and breast cancer in pre-menopausal women. rBGH has also been shown to raise insulin-like growth factor levels in the body, associated with an increased risk of breast cancer.

Styrene

Styrene can leach from polystyrene – a component of Styrofoam food trays, egg cartons, disposable cups and carryout containers – when heated, worn or put under pressure. Styrene is an animal mammary carcinogen and is possibly carcinogenic to humans.

• Know your plastics

Vinyl Chloride

Polyvinyl chloride (PVC) is used to produce food packaging. When PVC is made, vinyl chloride may be released into the air or wastewater. It was one of the first chemicals designated as known human carcinogen and has been linked to increased mortality from breast cancer and liver cancer among workers involved in its manufacture.

Phytoestrogens

Phytoestrogens are found primarily in soy food products. Although scientific evidence suggests that plant-based estrogens offer nutritional benefits, the data is more conflicting when it comes to breast cancer risk. Some studies suggest phytoestrogen consumption during adolescence may help reduce later risk of breast cancer, but other studies suggest it may cause oxidative DNA damage and interfere with breast cancer drugs.