Good Medicine: The Grave and Unseen Danger of Plastic

Plastic is everywhere, from takeout containers and couch upholstery to fertilizer and chewing gum. Derived from crude oil or natural gas, it is versatile and durable — but not fully degradable. Plastic waste makes up 40% of the garbage produced in the United States (40 million tons annually) and only 5% is recycled. It decomposes into rice-sized particles called microplastics and viral-sized particles called nanoplastics — collectively known as MNPs — which seep into groundwater and form massive islands in oceans. Plants take up these particles through their root system, and animals — including humans — ingest them.

Environmental scientists have discovered microplastics in soil layers 23 feet deep, prompting them to dub the 20th and 21st centuries “the plastic age.” Research confirms the presence of MNPs in our bloodstream and organs. We breathe in tiny airborne fibers floating off our synthetic clothes or car tires; we absorb them by using toothpaste, cleansers and makeup; we eat MNPs in fruits, vegetables and meat.

A widely publicized — and now debunked — 2019 study claimed humans consume 20 grams of microplastics a month. (That’s like eating a credit card every week.) It’s actually closer to 4 micrograms, but that tiny quantity accumulates and poses significant health risks, and 75% of it never leaves our bodies.

A landmark study published in the New England Journal of Medicine in March found that  MNPs in coronary artery plaques lead to a higher risk of heart attack, stroke or death. They have been detected in reproductive tissues like testes and semen, threatening fertility. They can also cross the blood-brain barrier and pass through the placenta. MNPs have been discovered in colon cancer cells and are believed partly responsible for the rising rate of bowel malignancy in those under 50.

Plastic is made with chemicals — many of them toxic — to increase its flexibility and water-resistance. But additives, like bisphenol A (BPA,) are known carcinogens and can cause autoimmune disease.

The full impact of MNPs on our health is unknown. Scientists have only recently been able to observe and count nanoplastics with the development of powerful imaging using two laser beams. One liter of water in a plastic bottle has 240,000 detectable nanoplastic particles — more than 100 times greater than previous estimates. Tap water, by comparison, has 5.5 particles per liter.

New York state has taken steps to minimize plastic waste. It banned single-use carryout bags in 2020 (with some medical transport exceptions), and NYS Assembly Bill A4943A, blocking the sale and distribution of foam cold-storage coolers by 2026, is awaiting Gov. Kathy Hochul’s signature. A second bill is in the works to remove toxic chemicals from the plastic packaging process.

You can protect your health by lowering your exposure to MNPs. Eat fresh, whole foods and drink filtered tap water, using a metal bottle when you’re on the go. Avoid clams, mussels and oysters (bivalves contain high levels of MNPs) as well as fast food (produced in factories using plastic machinery components). Don’t microwave meals in plastic dishes: in less than three minutes food is contaminated with billions of nanoplastics. Keep leftovers in metal or glass containers and consider bringing your own storage items when getting takeout. Don’t use plastic cutlery or cutting boards.

Do laundry less often and in cool water: Heat releases plastic microfibers from polyester, acrylics and spandex. One of the largest sources of MNPs in the home is the dryer lint trap, so consider hanging clothes outside on a nice day. Wear natural fibers, such as cotton, wool and linen.

If you buy plastic items, avoid containers with a number 3, 6 or 7 recycling mark: They have high levels of BPA. Use plastic-free cosmetics and personal products. When reading labels, keep an eye out for polyethylene, polypropylene, nylon and polymethyl methacrylate.

An active member of the United Nations Environment Programme, the U.S. has joined the global community to examine MNPs’ toll on human health, the environment and economies worldwide.

Dr. Mary Jenkins, a contributor to the Herald and member of its board of directors, retired after nearly 40 years as a family practice physician in New York state.