Consider what you’ve eaten today. Perhaps you drank juice from a plastic bottle, and coffee from a Keurig pod. For breakfast you might have had fruit with yogurt. Your lunch salad may have been packed in a Tupperware.
There’s a good chance much of what you ingested was packaged, stored, heated, lined, or served in plastic. And unfortunately, there’s mounting scientific evidence that these plastics are harming our health, from as early as our time in our mother’s womb.
Most of our food containers — from bottles, to the linings in aluminum cans, to plastic wraps and salad bins — are made using polycarbonate plastics, some of which have bioactive chemicals, like bisphenol a (BPA) and phthalates.
These man-made chemicals can leach from the containers or wrappings into the food and drinks they’re holding — especially when they’re heated. Research released earlier this year found that more than 90 percent of bottled water from the world’s leading brands was contaminated with microplastics, sparking a review of plastics in drinking water by the World Health Organization.
The main cause for concern is that these chemicals can mess with our hormones. Specifically, they can mimic hormones like estrogen, interfere with important hormone pathways in the thyroid gland, and inhibit the effects of testosterone.
Hormones are essential to our bodies’ ability to regulate itself; they function like little messengers, floating through the bloodstream and triggering different organs and systems to work together. Now imagine eating something that has a similar structure to your hormones and can act like hormones in your body. It can interfere with the delicate balance our bodies need to maintain. And that’s what ingesting even low doses of chemicals from plastic, over years, can do.
But because we’re exposed to these chemicals from many sources simultaneously, it’s tricky to measure their health impact. Even so, there’s compelling evidence that their “endocrine disrupting” capabilities have a range of disturbing health effects, from an increased risk of obesity and diabetes, to problems with reproductive development.
“Whatever organ or system under development in the fetus or child during an exposure could be altered in subtle yet significant ways, even at low doses,” Tom Neltner, the chemicals policy director at the Environmental Defense Fund, told Vox.
That’s why a major pediatricians’ group, the American Academy of Pediatrics, in July called on families to limit their use of plastic food containers, and demanded “urgently needed” oversight and reforms to the way these substances are regulated in the US.
But right now, that’s not happening. So, as pediatricians have suggested, you might want to rethink the plastics your food is stored in. Here’s what you need to know.
The complicated — and disturbing — science of plastics and animal health
The impact of the chemicals in plastics we commonly use for food storage have been studied in both animals and humans. And depending on the type of plastic polymer, the health effects vary from inconclusive to disturbing.
First, let’s walk through some of the animal research since it’s important here. (Researchers running animal experiments can zero-in on which doses of which chemicals cause certain health effects — something they can’t do in human studies — more on that later.) And let’s start with the most feared plastic polymer: BPA.
In aquatic animals, which are important models for human disease, BPA disrupts hormones in a variety of ways: as an estrogen imitator, blocking other sex hormones, and disrupting the thyroid hormone system. Researchers have noted that BPS — a compound that is structurally very similar to BPA — has similar effects on aquatic animals, but using BPS means manufacturers can claim their products are BPA-free.
In 2012, Harvard researchers published a study showing the effect of BPA on oocyte development (oocytes are the precursors to female eggs) in Rhesus monkeys. By either directly feeding the monkeys BPA or giving them an implant that would release specific amounts of BPA, the scientists ensured BPA exposures in the monkeys were comparable to exposures in humans. They found disruption in two critical stages of egg development, which could lead to lower egg quality and decreased fertility.
A 2008 meta-analysis of existing literature looked specifically into the effect of phthalates and polyvinyl chloride (or PVC) on asthma and allergies. They brought together mouse studies, case studies, and epidemiological data. While the human data was inconclusive, the review concluded that certain phthalates can cause an inflammatory response in mice.
A review published in 2009 looked at the existing literature on how plastic ingestion affects people and animals. It reported a wide range of effects that have been observed over the years: For example, adult male rats orally fed phthalates in oil had dysfunctional sperm development. Mice and guinea pigs fed phthalates also had testicular damage.
One of the biggest problems with drawing conclusions from animal studies is that many of them involve very high doses — several orders of magnitude higher than anything humans are exposed to, explained Dr. Frederick Vom Saal, an endocrinologist and professor emeritus at the University of Missouri, and one of the authors of the 2009 review. And that’s because much of the early research into plastic consumption was conducted by toxicologists, rather than endocrinologists, such as himself.
“For toxins, the more you’re exposed to, the greater the effect. [But] that is not true of hormones,” he said. “Hormones aren’t toxins; they’re regulatory molecules that operate at a trillionth of a gram level.”
In fact, hormones — and plastics that mimic hormones — are part of complex feedback systems in our bodies and don’t have a linear effect that’s directly related to dose. Vom Saal and his colleagues published a study in 2012 that found DEHP, a phthalate found in food packaging, had adverse reproductive effects in doses up to 25,000 times lower than had been previously imagined. They also noticed reproductive tract malformations in the male offspring of mice that were fed DEHP in oil.
Altogether, the animal research suggests that plastics can be harmful, especially to animals’ reproductive systems, and can cause abnormal sperm, egg, and fetal development.
The human data isn’t very reassuring
But again, not every health issue that arises in animals will arise in humans — since humans and animals are different. And definitive human studies of health effects from plastics exposure are hard to come by. That’s because the studies are mostly epidemiological — with epidemiological studies, researchers can only talk about associations between exposures and certain health outcomes. In other words, they can’t find causal relationships.
Another issue: It’s not always clear what compounds a package is made of because manufacturing plastic polymers also yields a lot of byproducts that aren’t necessarily tested for safety. Which means it’s hard to design studies to understand the effects of any single chemical.
Even so, Carl-Gustaf Bornehag, a researcher and professor at the Icahn School of Medicine at Mount Sinai, summed up, “Chemicals related to plastics — BPA in polycarbonates and phthalates in soft polyvinyl chloride — have been shown to be associated to human health effects in numerous studies, and effects have been shown in experimental cell and animal studies as well supporting the finding in humans.”
Reviews of the literature on the human health effects of chemicals in plastics have demonstrated links between exposures to BPA, phthalates, and other plastics additives and reduced fertility, reduced male sexual function and sperm quality, blunted immune function, type-2 diabetes, cardiovascular disease, and obesity. In fetuses, BPA exposure was correlated with an increased risk of miscarriage, low birth weight, and childhood obesity.
There are also potential cognitive effects. “Particularly strong are the associations between early BPA exposure and altered behavior and disrupted neurodevelopment in children, as well as increased probability of childhood wheeze and asthma,” the author of one of the reviews wrote. Indeed, children are at particular risk of health effects from these chemicals, AAP said: “Hormones act on all parts of the body, and even small disruptions at key moments in development can have permanent and lifelong consequences.”
A 2015 systematic review on children’s neurodevelopment and phthalate exposure concluded that prenatal exposure to phthalates was associated with “cognitive and behavioral outcomes in children, including lower IQ, and problems with attention, hyperactivity, and poorer social communication.”
While it’s true that many companies are now manufacturing phthalate- or BPA-free products, scientists are concerned about substitute chemicals, too. Again, many of them are functionally similar to the chemicals of concern, like BPA and BPS.
“The weight of the human evidence [on BPA] continues to mount,” Sheela Sathyanarayana, an associate professor of pediatrics in the department of environmental and occupational health at the University of Washington and Seattle Children’s Research Institute, summed up. “For phthalates, I do not see any controversies related to male reproductive toxicity and the weight of the evidence is extremely strong. I now consistently say phthalates ‘cause’ male reproductive abnormalities because the weight of the evidence supports it.”
The regulation of chemicals in food containers is weak
Right now, it’s up to consumers to manage their exposures to the chemicals in plastics because of a surprising lack of regulatory oversight over the plastic packaging industry.
In 1997 the FDA established the Packaging and Food Contact Substance program — a regulatory system to determine what packaging products were safe. So anyone who manufactures a “food contact substance,” which includes chemical additives, coatings, paper, or polymers, must first get the okay from the FDA before putting it on the market.
The exception to this rule is substances considered “Generally Recognized as Safe (GRAS)” — a category that was created for food items with a long history of use, like caffeine or sugar, and no evidence of harmful side effects.
But the list of GRAS-accepted polymers in packaging is long — some say too long. And it’s been criticized, most recently by the AAP. In August, members of the AAP’s Council on Environmental Health noted just how easy it is to get into the GRAS category due to very little oversight and significant conflict of interest. It’s one of the “critical problems within the food regulatory system,” they said, and it means these potentially harmful chemicals can be used in food packaging.
That’s because the FDA doesn’t actually test things that get put on this list. They leave the decision up to the manufacturing companies themselves. Consumer Reports noted that these companies don’t need to show any peer-reviewed evidence before placing their products on the GRAS list.
The US Government Accountability Office has reported that regulations for Generally Recognized as Safe products need to be tightened. An article published in PLOS Biology last year also criticized GRAS as part of the larger issue of “sluggish” federal regulatory policy that has failed in “considering scientific knowledge about the impact of exposures —particularly at low levels and during susceptible developmental stages.”
And last year, a group made of the Center for Food Safety, Breast Cancer Prevention Partners, Center for Science in the Public Interest, Environmental Defense Fund, and Environmental Working Group sued the FDA over the “secret GRAS system,” calling it “a regulatory scheme in which potentially unsafe chemical substances can be added to food based on conclusions by self-interested food and chemical manufacturers.”
In addition to the GRAS list, the AAP called out lack of proper assessment of controversial plastic packaging products like BPA and phthalates. “Of the nearly 4,000 food additives listed on the FDA’s Substances Added to Food website, data for effects on reproductive organs are available for less than 300, and only two have information about effects on development,” the group said in a statement.
One reason for this uncertainty is that our manufacturing abilities have whizzed past the slow nature of evidence-based research. Again, it is extremely difficult, if not impossible, to get the kind of evidence that would guarantee complete safety on these products, so the burden of proof is on regulators instead of manufacturers.
Another more insidious reason regulators may have been dismissive of scientists’ concerns is lobbying by the chemical industry. According to the Center for Responsive Politics, a nonprofit organization that tracks lobbying efforts, Dow Chemical, a plastics manufacturer, spent close to $14 million dollars in 2016 on lobbying Congress and federal agencies. And the American Chemistry Council — a large umbrella organization that lobbies on behalf of plastic manufacturers, among other groups — has spent between $5 and $13 million dollars on lobbying annually since 2009.
Regulators have also been criticized for their research into BPA’s health risks. The FDA-led CLARITY-BPA study, which began in 2012 and was released in the form of a draft report in February, gave BPA the green light, with a press announcement calling it “safe for the currently authorized uses in food containers and packaging.”
The final study is slated to come out sometime in September, and will be considered with results from other government-sponsored BPA studies at universities. This initial report’s early, positive conclusions were alarming to scientists who have been studying the chemical. In April, the Endocrine Society released a statement saying they “have significant concerns with the conclusions of the [report]” and criticized the methods and design of the CLARITY study.
What you can do to limit your exposure
In the absence of stronger regulations, there are things you can do to limit your exposure to chemicals in food:
- Eat fresh fruits and vegetables when possible, so that you avoid plasticized storage containers with chemicals that can leach into your foods.
- Don’t microwave food or drinks (including infant formula and pumped human milk) in plastic since heating up food containers increases the release of chemicals into food. Use glassware instead.
- Opt for glass or stainless steel to store your food.
- Avoid plastics with recycling codes 3 (which means it contains phthalates), 6 (styrene) and 7 (bisphenols).
But even if you do all these things, it’s impossible to totally avoid these common chemicals. BPA can be found on sales receipts and in plastic utensils. As a recent story in GQ, about the declining sperm count in men, points out phthalates are even more ubiquitous:
And the plastics that we may not directly consume end up in landfills, break down into microplastics, and can absorb harmful pollutants — all of which can enter our oceans, water, and food supply. So it’s no surprise that just about every American has measurable amounts of phthalates and BPA in their bodies. Still, any effort to reduce your exposure is probably worth it.