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What to Know About the Toxicity of Polypropylene

Reviewed by Dan Brennan, MD on April 27, 2021

Plastic has many uses in our everyday lives. You may think that plastic is safe for your health because of its widespread availability. However, some kinds are not. With many different plastic compounds to choose from, how do you know what’s safe for your health and what isn’t?

About Polypropylene and Other Plastics

Polypropylene is a soft, flexible type of plastic that is considered safer than other plastics. Polypropylene is most often used for:

  • Yogurt cups
  • Water bottles that have a cloudy finish
  • Medicine bottles
  • Ketchup bottles
  • Syrup bottles‌
  • Straws 

Research shows that plastic containers, plates, and bottles all contain chemicals that leach out into food when scratched or heated. The reason that the toxicity of polypropylene is lower than other plastics is because it doesn’t contain bisphenol A, more commonly called BPA. 

BPA is a synthetic estrogen used in plastics that are rigid versus being more flexible like polypropylene. These products include: 

  • Some water bottles‌
  • Food and formula container liners
  • Dental sealants
  • Shiny side of receipts‌

Plastic products are marked with numbers indicating the type of recyclability. If you see a recycling symbol with the numbers two, four, or five, they are usually safe for use. Polypropylene is marked with recycling number five.

Is Polypropylene Toxic?

Polypropylene is generally considered safe for use, but you should still be wary of using plastics more often than you have to. The chemicals found in plastic products are proven to contribute to some cancers.

While it's nearly impossible to avoid all plastic products, you can use as little plastic as possible. This is especially important if you're pregnant. The most important place to eliminate plastics is your food storage and preparation.

Keep in mind that if you see the recycling symbol with the number seven on your plastics, it may contain BPA. If number seven plastics are BPA-free, they will also be stamped with the acronym PLA or a leaf symbol.

Other studies show that BPA affects your infant’s brain development while in the womb. Pregnant women whose urine showed high levels of BPA were more likely to have daughters with anxiety, hyperactivity, and depression.

Continued

These symptoms were seen in girls as young as three years old. The study did not yield results to indicate why BPA affects girls in the womb and not boys. 

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You can reduce your risk of exposure to BPA in plastic products by:

  • Investing in a glass, steel, or ceramic water bottle to refill
  • Eating less canned food
  • Avoiding canned formula for your baby
  • Checking for plastic products that say they are BPA free
  • Washing your hands thoroughly after handling receipts from stores
  • Not cooking or heating food in plastic containers
  • Not using roasting or steaming bags to heat your food
  • Avoiding hard plastics like clear containers
  • Microwaving food using glass or ceramic 
  • Not putting plastic containers in the dishwasher, where the heat may cause chemicals to leach out onto other dishes

Because BPA is known to cause cancer, many plastic products carry a “ BPA-free” label. Look for this when you do purchase plastic products for your home. While you’re reading labels, beware of plastics that say they are microwave safe. That doesn’t indicate a lack of chemicals used in processing to make the plastic. You should never microwave plastic if it can be avoided.

Pros of Polypropylene

The toxicity of polypropylene was tested alongside other types of plastic. Results showed that unknown chemicals are present in most plastic products. The toxicity of BPA is proven, but other chemical impacts on your health are largely unknown. Polypropylene is a better alternative than plastics that contain BPA. Still, you should avoid using plastics with your food whenever possible.

Cons of Polypropylene

Phthalates are chemicals used to soften plastic, making it more flexible or changing its shape for different uses. You may be exposed to phthalates through:

  • Inhaling – Phthalates may be used in solvents, turning them into fumes that are breathable‌
  • Ingestion – When you eat foods that were wrapped or stored in plastic, phthalates may seep into your food.
  • Chewing – Phthalates may be in children’s toys. If your baby chews on plastic toys, they are exposed to chemicals inside the plastic.‌
  • Touch – If you use lotions or perfumes stored in plastic bottles, phthalates absorb into the substances and then into your skin.

‌Phthalates and BPA are dangerous because they can cause:

  • Cancer
  • Asthma
  • Hormone imbalances
  • Developmental delays‌
  • Reproductive problems
WebMD Medical Reference

Sources

SOURCES:

Breast Cancer: “Exposure to Chemicals in Plastic.”

Children’s Environmental Health Network: “FAQs: Plastics.”

Consumer Reports: “Most Plastic Products Contain Potentially Toxic Chemicals, Study Reveals.”

Stanford University News: “Bisphenol A facts.”

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