The consequences of convenience on the human body
By Kit Stolz 07/05/2012
A revolutionary change overtook America beginning in the l960s, and it’s one that had nothing to do with the usual suspects — long hair, war, sex or rock and roll.
It was an environmental change, but American pop culture noticed it long before mainstream science and medicine awoke to its consequences.
A movie put it to us as succinctly as possible. In The Graduate, a naive, confused college grad, representing his generation, was given advice from a businessman named McGuire.
“Ben, come with me for a minute,” McGuire said, taking Ben (played by Dustin Hoffman) aside at his homecoming party. “I just want to say one word to you – just one word.”
“Are you listening?”
The scene always gets a big laugh, but 45 years later, environmental scientists, doctors and researchers who specialize in diseases of the hormonal system are not so amused. They know that the amount of plastic in our lives has exploded, and in countless peer-reviewed studies over the last 15 years, they have linked the result to alarming changes they see in our bodies, our lives and our environment.
The rise of plastics — and obesity
When it comes to careers, what McGuire said to the young graduate was excellent advice. In the U.S. and around the world, the plastics industry grew more than 15 percent a year from l960 until l974, up to the first oil shock, and since has continued to grow about 8 percent a year worldwide. In l960, about 7,000 tons of plastics were produced. It’s more than 300 million tons a year today, according to industry analysts Pardos Marketing.
To put it another way, Susan Firenkel, author of Plastic: A Toxic Love Story, points out that in 1960 the average American went through about 30 pounds of plastic a year. Today it’s more than 300 pounds per person.
With the massive upsurge in the use of plastics has come a concurrent rise in exposure to chemicals from plastics that mimic human hormones in the bodies of Americans. According to a 2004 study backed by the Centers for Disease Control (CDC), a government health institute, 95 percent of Americans have the plasticizer BPA — the best-known of hormone mimics — in their urine. Other studies have replicated the result: one found BPA in 93 percent of Americans’ blood.
At the same time, in just the last 30 years, obesity rates have more than doubled in the United States. Many researchers suspect that “endocrine disruptors” — hormone mimics — have a hand in this explosion of weight, estimated to cost the country about $150 billion a year.
Scientists often remind listeners that “correlation is not causation.” To make the point unmistakably, Bruce Blumberg, a molecular biologist at UC, Irvine, and perhaps the leading researcher into the link between chemicals from plastics and the concurrent rise in obesity in this country, sometimes jokes that the rise in obesity in America could be correlated not just to chemicals from plastics, but also to the rise in the number of health clubs around the country, not to mention global warming and the number of SUVs on the road in Southern California.
Bruce Blumberg, molecular biologist at UC, Irvine
But when Blumberg stops joking, he points to an avalanche of evidence — from molecular studies, cell studies, animal studies and epidemiological studies — showing that endocrine disruptors change the way our bodies gather fat. It’s especially hard to dismiss his point when it comes to the study of young people born into the plastics boom.
“It is intuitive that kids today spend more time in sedentary activities, but the evidence suggests that teen activity has not changed substantially in the last 20 years,” he said. “Yet we continue to hear that exercising more and eating less will cure the obesity epidemic. I think that exposure to endocrine-disrupting chemicals, along with over-consumption of simple starches and sugars, plays a very important role in the obesity epidemic in the U.S.”
In 2006, Blumberg and a fellow researcher coined a word — obesogen — to describe compounds that push our bodies toward producing more fat cells, toward producing fat cells that store more fat and, most seriously, toward visceral fat, the storage of fat inside the abdominal cavity, away from the skin.
At the time he thought the word was obvious and probably already in use. In fact, it’s a new word, just as the fact that nearly 70 percent of the country is obese or overweight — according to the CDC — is a new reality.
Here’s an example of his research: Hearing that an obscure pollutant used in pesticides and marine products — tributyltin, or TBT – in Japan actually reversed the sex of two species of fish, from female to male, Blumberg and his laboratory set out to find what cell receptor the chemical worked on in other life forms. They expected to find that the chemical bound to receptors in cells that governed whether an embryo early in its development would turn out to be male or female. They tested TBT on snails, and found that TBT made the male snail penis grow to an absurdly large size, making it “a geometric problem” for snails to mate and resulting in what researchers now term “imposex.”
But when TBT was tested on mice, which more closely resemble humans, it made them fatter.
“It made fat deposits bigger, and the mice gained weight over time,” he said. The TBT-exposed mice ate exactly the same amount of the same food as normal mice. Their fat cells did appear to store a little more fat from the food, but more importantly, their bodies generated many more cells in which to store fat.
Further, like embryos, adults also have a number of stem cells that can take on different forms in the body. These mesenchymal stem cells, although not as infinitely variable as their better-known counterparts, the embryonic stem cells can become bone or cartilage or even nerve or muscle, but when exposed to obesogens, they mostly become fat cells.
“The reality is that fat cells live about 10 years,” Blumberg said. “The fat cell population is regenerated from this stem cell population [in your body], and every year about ten percent of your fat cells turn over.”
On a molecular level, researchers found that TBT exposure led to fat-cell generation. In the test tube, human cells exposed to TBT accumulated fat — specifically, triglycerides, a known health risk. And, Blumberg added, the same fat-cell generation was documented in people exposed to Avandia, which was once the most popular drug for diabetes. It was prescribed to reduce blood sugar levels in patients, which it did, but it also made them fatter and, it turned out, more prone to heart attacks and strokes. After an estimated 47,000 needless deaths worldwide, the drug was pulled from the market in Europe in 2010, and restricted in the U.S.
“If a drug that people take causes them to become fat by increasing the number of fat cells [in the body], why would you imagine that a chemical that has the same effect on the [stem cell] receptor wouldn’t give you the same consequences?” he asks.
Although it’s very expensive at present to measure the tiny amounts of TBT in the environment and in our bodies, Blumberg said, “The little data that we have suggests that TBT [concentrations] are present in [humans] at the levels we require in animals to get the effect.”
These levels are tiny — as low as one to five parts per billion — but because these chemicals mimic tiny amounts of hormones produced by organs in the body, such as the brain, the effects can be huge.
Sarah Janssen, a physician and scientist who works for the Natural Resources Defense Council, explained it this way: “If you’ve lived with or remember being a teenager, and what puberty is like, you have experienced the difference in circulating levels of hormones going from a parts-per-trillion concentration, in a child’s body, to a parts-per-billion concentration, as a teenager. Small doses have a profound effect on our physical, sexual and mental functioning.”
Blumberg stops short of saying he has proof that TBT chemical is making us fat, but he points out that the chemical is just one of dozens of endocrine disruptors suspected of increasing our fattiness. Others include DES, once prescribed as a drug; PCBs and PCDEs, two pollutants that persist for decades in the environment; PFOAs, which are found in flame retardants, and plasticizers such as BPA and the phthalates, which make plastics moldable and soft.
And fattiness, although a serious problem, especially in the United States, is not what researchers fear most about our exposure to the endocrine disruptors in products such as plastic water bottles, canned foods and receipts. It’s worse, much worse. They’re also concerned about well-documented links to early onset of puberty, sexual dysfunction and infertility, mental and behavioral issues, diabetes and cancer.
Disruptors in the environment
For years, doctors and researchers have been concerned about the risk of pharmaceutical hormone mimics such as DES, which was once prescribed to women to reduce miscarriage but turned out to be a carcinogen. But some of the most dramatic consequences of exposure to low levels of endocrine disruptors first showed up in the environment.
Sean Anderson, an environmental scientist at California State University, Channel Islands, points out that only in the last few years have scientists been able to actually measure and assess the effects of low concentrations of the endocrine disruptors.
“We can take some of these substances, such as DDT or PFOA [found in flame retardants] and give it to me at a parts per million dose, and I’ll be OK, or even give it to my son, and he might be OK, but give it to my wife on one day when she’s pregnant, and see massive effects on the development of the embryo,” he said. “It’s a whole different way of thinking about toxicology. These compounds are screwing with the cell-to-cell, molecule-to-molecule dance that happens as we develop.”
Some of the most dramatic effects were first observed in Florida, near Lake Apopka, in the early l980s, where University of Florida ecologist Louis Guillette was trying to find out why alligators were failing to reproduce. He discovered that male alligator penile length was shrinking.
“To go measure the length of alligator penises, that’s an interesting job,” Anderson noted. After years of research, Guillette showed that the “feminization” of alligators, which prevented reproduction, was linked to a pesticide called dicofol, which is chemically related to DDT.
“The feminization of populations is particularly interesting to ecologists now,” Anderson said. “These compounds may not outright kill mature fish or birds, but the populations can’t reproduce. The number one producer of DDT in the world was Montrose Chemical in L.A., and the greatest concentration of DDT breakdown products in the world, by far, are still present in the sediments near the outfall pipe off Palos Verdes.”
Although DDT was banned in l972, and what was once Montrose Chemical is now a toxic superfund site under the jurisdiction of the Environmental Protection Agency, the DDT worked its way up the food chain to bird populations in the Channel Islands in the l980s, wiping out bald eagles, threatening the brown pelican population, and producing some bizarre feminizations in the bird populations that survived, such as lesbian seagull couples that, against all odds, still managed to raise chicks.
Bald eagles were recently reintroduced to the Channel Islands, and have begun to breed successfully, and pelican populations have recovered in Southern California and been removed from the endangered list; but researchers are seeing similar, if less dramatic effects, on human populations in Europe and the United States.
“People in the field are very concerned about this and think it’s a very serious problem,” said Shanna Swan, a researcher at Mt. Sinai Hospital in New York who has published nearly 150 papers on endocrine disruptors. She has focused on the phthalate plasticizers, such as BPA and DEHP, which are used to soften the common PVC plastic. These disruptors have been found in food, milk and drinking water, and are found in countless plastic products, including flooring, furniture, packaging, cars, fragrances, soap and hospital plastics such as IV bags. These disruptors can be absorbed through the skin as well as in food or drink, and will cross the placental barrier to impact embryos in the womb.
Shanna Swan, researcher at Mt. Sinai Hospital in New York
“In Europe, sperm counts have declined about 1 percent a year for 50 years, at the same time we’ve seen a rise in testicular cancer,” she said. “Fertility rates are falling, and even with artificial insemination and assisted reproduction couples are often not able to have two children, even though we know from the rise in adoption that they want to.”
Swan in recent years has published papers linking exposure to several different plasticizers in common use to genital alterations and changes in behavior in American boys. Although a well-known leader in the field, her research has been attacked by the American Chemical Council, an industry group, which she interprets as an attempt to spread doubt about a known health risk, comparable to the attacks on researchers into the dangers of smoking years ago by the tobacco industry.
“I think, if you look at the evidence, you have to be very concerned,” she said. “For me it’s a problem of the magnitude of global warming.”
More regulation or consumer action?
Some leaders in the field believe that more regulation is necessary to protect the public from disruptors. One such proponent is Laura Vandenberg of Tufts University, who in March, with a dozen other well-known researchers, published a definitive paper for The Endocrine Society showing that “environmental exposures to low doses of endocrine disruptors are associated with human diseases and disabilities.”
Vandenberg says she tries hard to reduce her exposure to disruptors, avoiding canned foods and plastics and not taking receipts (which are commonly coated with a dust that contains the disruptor BPA). But she doesn’t think that’s enough, and — like many other scientists interviewed for this story — believes we need government regulation to keep us healthy.
“We can’t avoid these chemicals,” she said. “It’s not like we can solve this problem by shopping in one aisle of the grocery store and not another.”
Blumberg believes the evidence supports the need for regulation by federal agencies such as the U.S. Department of Agriculture, the Environmental Protection Agency, and the Food and Drug Administration, but adds, “I seriously doubt anything will happen in a regulatory sense anytime soon.” Blumberg strongly advises people to avoid processed foods and to eat fresh foods not treated with pesticides or chemicals. He also hopes that better labeling and “green chemistry” products and packaging will reduce our exposure to disruptors.
For Swan, it’s not a case of either/or.
“I think both are needed,” she said. “Consumers cannot choose to buy products that are free of their chemicals because they’re not labeled. It’s great for people who have the information and the training to learn how to avoid these chemicals, but mothers shouldn’t have to become chemists to avoid harming their children with common household products.”
Swan points to one hopeful sign: Several studies, including a study to be released later this month on Mennonite families in upstate New York, show that people who take care can reduce the levels of disruptors in their blood and urine.
“We looked at Mennonite women who grow their own food and make their own clothes and found a significantly reduced exposure,” she said. “There are several of these studies, and they all show that if you eat clean food and change your lifestyle to avoid exposure to processed foods and personal household products that contain these chemicals you can have some control over the levels of endocrine disruptors in your body.”
Products to avoid and why
By Kit Stolz
Because there are so many endocrine disruptors [endocrine-disrupting chemicals, edcs] in our man-made environment and in our food, any short list of products and their potential dangers will be incomplete. Many of the researchers interviewed for this story recommended the Environmental Working Group for edc advice, but they specifically said they avoid the following products:
Thermal receipts (BPA)
ATMs, gas stations and many other outlets use receipts coated with bisphenol-A, or BPA, a thermal disruptor that mimics estrogen, and has been linked to early onset of puberty, adult onset of diabetes and genetic abnormalities, among other serious medical consequences. BPA is estimated to be about 3 percent of the common PVC plastic, but it’s especially likely to pass into the body through contact with receipts. Scientists such as Dr. Pete Myers, of Environmental Health Perspectives and runs the Environmental Health Services news wire, recommend avoiding receipts and washing hands after handling. “BPA-free” doesn’t mean risk-free: products can use instead a related compound, BPS.
Anti-bacterial soaps (triclosan)
Hand soaps and detergents usually contain triclosan, an endocrine disruptor which the American Medical Association has specifically recommended against in the home. It’s also found in toothpaste, face wash and deodorant, as well as mattresses, insoles and other products.
Canned foods (BPA)
A thin layer of plastic inside cans contains BPA, and it’s believed to be a significant source of this disruptor into American diets. Children and pregnant women in particular should avoid canned foods, tests by the Environmental Working Group (EWG) have found.
Microwavable popcorn (PFOA)
Microwaveable popcorn bags, flame-retardants, ski waxes, rain gear and Teflon are just some of the products that transmit this endocrine disruptor to Americans. One analysis found it in the blood of 98 percent of our citizens, though it has been linked to thyroid problems, infertility, and lowered IQ.
Plastic bottles (BPA)
A Federal panel that considered the safety of plastic bottles in 2007 found “some concern,” especially for children and pregnant women. Heat and wear to the bottle increase the risk.