Dr. Shanna Swan will be a featured guest at Moms Clean Air Force’s Plastic: A Health Crisis in Plain Sight convening on April 3. Register to watch the livestream of this event.
It’s exceedingly hard to capture—and hold—public interest in how plastic harms human health. Dr. Shanna Swan, PhD, an award-winning environmental and reproductive epidemiologist, knows this difficult push-pull better than most; she has been researching the health impacts of endocrine-disrupting chemicals (EDCs) and how they interfere with our body’s hormones for decades, especially when it comes to sperm count. Sperm decline captures attention, and yet we’re all still living lives laden with EDC-filled plastic—and willingly purchasing more daily.
A new documentary—and simple steps
Dr. Swan, an environmental medicine professor at Ichan School of Medicine at Mount Sinai, is uniquely positioned to bridge the divide between research and action in a new documentary from The Cove director Louie Psihoyos. The film is currently in post production, not yet available to watch, but here are the basics: Dr. Swan meets six couples from all over the United States who are having trouble getting pregnant. They get sperm and urine tests, and Dr. Swan weighs in on the results, noting plastic items in their very own homes that can mess with hormones—from flexible plastic shower curtains to food storage containers.
“I walk through their house with them,” she says, all while explaining environmental factors that can impact fertility: possible exposures at work, drinking water, and indoor air pollution. Next, the couples swap their daily products with safer ones condoned by Dr. Swan. Does exposure go down? Do hormones, sperm count, or even pregnancy test results change? She won’t reveal any spoilers but shares that questions get answered to varying degrees.
Until the film comes out, there are simple steps anyone can take to safeguard health. It’s relatively easy to stop using items, from face cream to plastic water bottles, known to contain chemicals that can mimic or disrupt hormones.
Not sure how? Dr. Swan will be at Moms Clean Air Force’s Plastic Summit on April 3. There she’ll discuss the latest research on the perilous impacts of plastic on the human life cycle—and the science behind simple product switches. Those seeking knowledge can register now for the livestream.
REGISTER FOR A HEALTH CRISIS IN PLAIN SIGHT ON APRIL 3
The link between hormones and plastic
It doesn’t require a science degree to understand that chemicals specifically meant to disrupt our endocrine system can shift hormones in our bodies; birth control pills are an obvious example. But it’s less straightforward to understand how plastic messes with our hormones.
Plastic is a very large class of materials varying from soft and flexible to hard and durable. There is plastic in products designed to be absorbed by the body, like makeup, but pretty much all plastic in any form can and does wind up in the human body. Not all plastics impact us similarly—there are distinctions. “There is plastic and then there are plasticizers. Plastic is the material and plasticizers are the materials put into the plastic to change its function,” Dr. Swan explains.
Tens of thousands of chemicals can be classified as plasticizers, and not all have been tested for human safety. “Many of these can affect the hormones in any living organism. Think of hormones as things manufactured in glands in the body that send signals to other parts of the body to make things happen. They are messengers.” Plastic chemicals can interfere with the messengers. “If you get those messengers wrong and they are misfired, lots of bad things can happen. Hormones are essential for the normal function of the body,” she says.
Choosing to focus on sperm
Endocrine-disrupting chemicals can do many things. “I care about the ones that impact reproduction,” says Dr. Swan, who studied miscarriages at the start of her career. She shifted her focus while working to confirm a 1992 Danish paper concluding sperm count had declined 50% in 50 years. This made Dr. Swan want to know why. Also, focusing on men was easier. “Women’s genitals are not visible and are much harder to study. For a man it all hangs out. For a man to give a sperm sample is easy. For a woman to give an egg sample? Forget it. This is one reason why we know much less about the impacts of these chemicals on women.”
Dr. Swan studied sperm count in different locations across the United States to determine if environment matters. Yes, she determined, it sure does. Men in Missouri, with its ample corn- and soy-dotted farmland heavily sprayed with pesticides, for example, had half as much sperm as men in Minnesota.
“I was getting closer,” she recalls this discovery. In 2017, she published her own game-changing sperm study, the basis of her 2021 book, Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race. In 2022, she updated the study: the rate of decline is faster than previously reported—and not just in the U.S. but worldwide.
Why don’t people know about this?
To promote her book, Dr. Swan went on Joe Rogan’s podcast. “He said, ‘Are you saying that toxics in the environment are threatening the survival of the human race?’ And I said, ‘Yes.’ And he said, ‘Why don’t people know about this?’ and put his hands up.” Dr. Swan took this as a challenge to find a way to ensure people know about this.
Dr. Swan has published more than 200 scientific papers over her illustrious career. Traditional studies, like those funded by the National Institutes of Health (NIH) are critical for establishing solid causal inferences, and we need them, Dr. Swan says. But inspired by her conversation with Joe Rogan, she’s now trying to “involve people” with Action Science Initiative (ASI), a three-faceted program at the nonprofit Environmental Health Sciences. Step one is short interventions with people concerned about an aspect of their health or environment, like those showcased in her upcoming documentary. Step two is communications. Step three is strategy—how to make changes in the world, from legislation to commerce.
ASI is inexpensive and doesn’t require big machinery, making it especially compelling today, as federal science funding is being decimated and researchers are vying for limited foundation funding. “In terms of academic funding, it’s devastating. We are going to have to rely on Europe and China. Any progress will be lost. It’s just terrible,” says Dr. Swan. While she can’t say how profound the impact will be or even imagine how the research enterprise will continue, she’s simultaneously showing the way: A true maverick scientist.