Your Health Checkup: Plastics Good and Bad

There are different health risks associated with different plastics. Find out which ones are safer to use and which ones should be avoided.

Person cutting through a discarded plastic bottle with a fork and knife.

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“Your Health Checkup” is our online column by Dr. Douglas Zipes, an internationally acclaimed cardiologist, professor, author, inventor, and authority on pacing and electrophysiology. Dr. Zipes is also a contributor to The Saturday Evening Post print magazine. Subscribe to receive thoughtful articles, new fiction, health and wellness advice, and gems from our archive. 

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A technician from a water analysis company recently visited our home to test our water supply. Fortunately, our water passed the test. Our discussion evolved to the plastic carriers used to contain water, and I learned about different health risks associated with different plastics.

I have written previously that we ingest about five grams of plastic each week in the form of nano- and micro-plastics. These are plastic particles smaller than five millimeters in size that contaminate our food, water, and even the air we breathe. Five grams is approximately the amount of plastic in a single credit card.

What I learned from the technician was that plastic containers are stamped with a numbers guide that identifies the type of plastic and its recyclability. Because substances in the plastic can leach out into the water and be ingested, the number — typically enclosed in a recycling symbol located at the side or bottom of the container — can be used to distinguish safer plastic from those not so safe.

Safety Guide for Plastics

Plastic #1 contains polyethylene terephthalate used to package a variety of substances including cosmetics, household cleaners, water, juice, soft drinks, salad dressings, peanut butter, and oil. High temperatures can leach out antimony and phthalates in the plastic, which are toxic to the body. This plastic container should be used with caution and not be reused.

Plastic #2 contains high-density polyethylene made from petroleum and can withstand high temperatures. It is used for packaging laundry detergent, milk jugs, and plastic bags. There appear to be no health concerns.

Plastic #3 is polyvinyl chloride, also known as vinyl and found in shower curtains, cling wrap, teething rings, toys, car interiors, vinyl flooring, and vinyl IV bags. It can leach out lead and phthalates among other things. It is toxic and products made from, or containing, polyvinyl chloride should be avoided.

Plastic #4 is low density polyethylene commonly used to produce grocery bags, food storage, juice and milk cartons. There appear to be no health concerns.

Plastic #5 is polypropylene commonly used for bottle caps, storage containers, plastic cups and baby bottles, kitchenware, yogurt cups, and margarine tubs and appears to have no health issues. While it is microwavable and dishwasher safe, that just means the plastic will not warp when heated. Glass containers are preferable when microwaving.

Plastic #6 is polystyrene, also known by the brand name Styrofoam, commonly used for disposable knives and forks, egg cartons, foam cups, and restaurant to-go packaging. Long term exposure can leach out chemicals that can cause cancer, neurologic or blood problems. Left over foods from a restaurant should be repackaged in glass or stainless-steel containers, and Styrofoam cups, plates, and plastic utensils should be avoided.

Plastic #7 is a catch-all category that includes a variety of plastics that may or may not contain bisphenol A (BPA), commonly used in making polycarbonate plastic and epoxy resins. BPA can be found in liquid infant formula cans, food storage containers, toys, and plastic baby bottles. It can mimic the effects of the female hormone estrogen and cause a range of adverse actions. The letters PC may be present within the recycling symbol to indicate polycarbonate. This plastic should be avoided.

In summary, search for #2, #4, and #5 plastic products for the safest choices. Avoid exposing any plastic to high temperatures such as microwaving and dishwashing and wash by hand with a mild detergent. When possible, choose glass or stainless steel instead of plastic for all food containers.

My unplanned chat with the water technician led me to reconsider the use of plastic in general and specifically for food and beverage containers. Avoiding all plastic when possible seems like a reasonable but probably not doable conclusion. Therefore, search for the number inscribed on all plastics to avoid using numbers 1, 3, 6, and 7.

Featured image: Shutterstock

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