The substances in plastic cups, plates, forks, spoons and other utensils and containers affect us more than we think. Vox science journalist Julia Belluz talks about the main research and the scientists’ cautions.
How dangerous polymers and microplastics affect hormones
Almost everything we eat is sold, stored or heated in plastic containers. Bottles, food film, coating in aluminum cans, disposable dishes – most packaging today is made with polycarbonate plastic. Some varieties contain bioactive chemicals such as bisphenol A and phthalates. They can seep from the packaging into the food, especially when heated.
More and more evidence is emerging that they are harmful to our health. For example, according to a recently published study, more than 90 percent of bottled water from the world’s leading manufacturers is contaminated with microplastics. These are particles less than 5 millimeters long. Once in the body, they lead to hormonal disorders. In particular, they mimic the work of estrogen, interfere with the thyroid gland and inhibit the action of testosterone.
As we know, hormones are one of the key regulators of our body. They carry information by moving through the bloodstream and triggering certain processes in the organs. Now imagine that you have eaten something similar in structure to a hormone and acting in a similar way. This could upset the delicate balance within the body.
This is what happens when small doses of plastic chemicals are ingested over the years. And it starts in childhood.
Another prominent scientist, Tom Neltner, director of chemical policy at the EDF (Environmental Defense Fund), also confirms the concept of plastic dishware harm:
“Any organ or system developing in a fetus or child can be significantly altered by exposure to chemicals from plastic, even from small doses, but it’s very difficult to notice”.
So it’s no surprise that in July 2018, the American Academy of Pediatrics urged parents to limit the use of plastic containers and also demanded an urgent review of how these substances are regulated.
On what basis were the conclusions drawn?
Scientists today use animals as models to study human diseases: mice, hamsters, monkeys and others. In general, studies on animals show that plastic can cause significant damage to the body, especially the reproductive system, if it regularly enters the esophagus. It can cause abnormalities in the development of sperm, eggs and fetuses.
In 2012, Harvard scientists published a study on the effects of bisphenol A on female germ cell development in rhesus monkeys. They gave the monkeys the substance with food or implanted an implant that released a certain amount of it. This led to abnormalities in two critical stages of oocyte development. That is, the ingestion of the plastic led to decreased fertility.
Why these particular organs? Hormones and the plastic particles that mimic them are part of the body’s complex feedback systems. For example, phthalates and polyvinyl chloride cause an inflammatory response in mice and possibly provoke asthma. And plastic ingestion has caused problems with sperm development in rats and testicular damage in mice and guinea pigs.
However, based on animal studies alone, it is impossible to draw unequivocal conclusions. In the old works, scientists used very high doses of substances (several orders of magnitude higher than humans can get). That’s because the early studies were done by toxicologists, not endocrinologists.
Endocrinologist Frederick Vom Saal of the University of Missouri notes the following observations:
“As for toxins, the more you get, the stronger the effect, but that’s not the case with hormones. Hormones are regulatory molecules that act at the level of one trillionth of a gram”.
According to this scientist’s study, dioctyl phthalate has negative effects even at doses 25,000 times lower than those previously considered dangerous. And the male offspring of those mice given the substance develop genital tract deformities.
How else does plastic affect the human body?
Not all health problems that arise in animals will necessarily appear in humans. We are, after all, built differently. The problem is that it is difficult to establish unambiguous cause-and-effect relationships. More often than not, scientists can only say that contact with plastic affects certain health indicators.
There is another problem. It’s not always clear exactly what components went into the packaging. When plastics are made, there are many by-products that are not always tested for safety. Therefore, it is difficult to identify the effect of each individual chemical.
Nevertheless, according to researcher Carl-Gustaf Bornehag, the link between chemicals in plastics and negative effects on human health has been noted in a number of studies. And experiments on cells and animals confirm these conclusions. And these conclusions are quite disappointing:
When plastic microparticles enter the body frequently, fertility, male sexual function, immune system, risk of type 2 diabetes, cardiovascular disease, and obesity are primarily affected.
In addition, plastic chemicals affect cognitive function. Exposure to bisphenol A at an early age is associated with impaired brain development, as well as an increased risk of childhood shortness of breath and asthma. And exposure to phthalates during fetal development can lead to low IQ, attention problems, and communication difficulties.
Although many companies now make phthalate- and bisphenol A-free plastics, scientists question the safety of their equivalents: many of them function similarly to the harmful substances they replace.
What should we do to reduce the harmful effects of plastic on the body?
Experts recommend that you develop these four habits:
- Try to eat fresh fruits and vegetables. This will reduce the risk of chemicals from plastic packaging getting into your food;
- Don’t heat food in plastic utensils;
- Store food in glass or metal utensils;
- Do not use plastic utensils with recycling codes 3 (contains phthalates), 6 (styrene), and 7 (bisphenols).
Unfortunately, these habits do not guarantee 100% that plastic will not get into your body. Why? Because polymers are not only in cookware today, but everywhere. Bisphenol A can even be found on cash register receipts and boxes today. And phthalates are even more common. They are present in medications and the coating of food additives, in thickeners, lubricants and emulsifiers. And also in medical devices, cleaning products, paint and plasticine, fabrics, sex toys, liquid soaps and nail polish.
Those substances that do not enter our bodies directly end up in landfills. They gradually decompose to microplastics and absorb harmful compounds, all of which then end up in water and food. Nevertheless, any attempt to reduce the amount of plastic in our bodies is worthwhile.