“This might be the first generation where kids are dying at a younger age than their parents and it’s related primarily to the obesity problem.” – Actress Judy Davis
Celebrities like Judy Davis aren’t the only ones worried about the obesity epidemic. It is on the minds of millions of Americans. It is also worrying — even frightening — public health officials.
Obesity is the fastest-growing cause of disease and death in the United States according to the U.S. Surgeon General. A full third of Americans suffer from obesity, and another third are overweight. That means two-thirds of the American public are either obese or overweight!
Why is this so worrying? Obesity is associated with diseases such as diabetes, cardiovascular disease and high blood pressure.
Puzzling trend: Obesity in the babies
The growth of fast food chains and our dependency on cars seem to be among the obvious explanations for our society’s collective weight gain. So why would scientists look beyond poor diet and lack of exercise for answers?
Epidemiologists find obesity trends very puzzling. Not only are more adults becoming obese, but so are very young children and even infants. One third of babies nine months or younger are overweight or obese, compared to just 18% twenty years ago. That’s nearly double.
These infants aren’t eating fast food or developing bad exercise habits. They’re on a milk-only diet and can’t walk.
What’s going on here?
“Obesogens”: Chemicals that can contribute to obesity
As scientists search for answers, they’re finding disturbing links between obesity and certain chemical exposures. Researcher Bruce Blumberg has coined a new term for chemicals that can disrupt normal metabolism and contribute to obesity: “obesogens.”
Early life: Obesogens make stem cells develop into fat cells
Epidemiological studies have shown associations between certain chemicals and obesity in adults, but perhaps the most disturbing finding so far is that obesogens appear to have the greatest effects during early stages of development. This is a striking example of how toxic chemical exposures before birth or in the first few years of childhood can cause negative effects that last for the rest of our lives.
Every cell in our body starts out as a stem cell before it becomes a specific cell type, such as a muscle cell or skin cell. Experiments show the chemical tributyltin (TBT), a paint additive, predisposes stem cells to become fat cells rather than bone cells.
Another potential obesogen is bisphenol A (BPA), used in food can linings, polycarbonate plastics, and even paper receipts. A study published in the journal Endocrinology showed that exposure to BPA both prenatally and just after birth led to metabolic deficiencies and body weight increases.
Can taking a shower make you fat?
Phthalates are a large class of chemicals found in everything from fragrances to medical devices. Human epidemiological studies have correlated exposure to certain phthalates with increased fat mass and larger waist circumferences.
People use an estimated four million tons of phthalates every year. They’re used heavily in polyvinyl chloride (PVC) products like vinyl shower curtains and flooring, and can also be found in paints, lubricants, and nail polish, to name just a few of many uses.
Can cooking a healthy meal make you fat?
Next time you try to cook a healthy meal, make sure your pan isn’t undoing your efforts. The surfaces of many non-stick pans are made using the chemical PFOA, and if overheated, chipped, or scratched, the chemical may be released.
In animal studies, in utero exposure to PFOA was shown to alter the levels of hormones involved in metabolism and cause excess weight gain in offspring. These observations add to PFOA’s list of toxic effects — it is already known for its developmental and systemic toxicity.
Obesogens are very hard to avoid
These few chemicals, already enough to make us worry, aren't the whole story. Research continues on others suspects too, such as the flame retardants known as PBDEs, and as more studies are done, even more chemicals may be found to have obesogenic effects. The prevalence of obesogens in our lives works against any of us who are trying to be healthy, and threatens to undermine our public health officials' best efforts.
We can try to avoid obesogens and other toxic chemicals. We can spend hours researching products and chemicals on our own. We can scour the Internet for safe alternatives. But that’s a lot to ask. How many of us have the time or expertise to sort through all the options, or the luxury of avoiding certain products or foods? In a recent blog post, José Bravo, Executive Director of the Just Transitions Alliance, calls this issue a matter of environmental justice.
Even if we could dedicate all the time in the world to avoiding obesogens, at best we’d only be able to avoid those that scientists have identified. Thousands of other chemicals haven't been evaluated, so we have no clue whether or not they may be obesogenic. There has to be a better way.
Let’s fix the law
The Toxic Substances Control Act (TSCA), enacted in 1976, is one of our oldest and least effective environmental laws. It desperately needs to be reformed. TSCA allows companies to use chemicals in products sold to millions of people, without requiring their safety to be shown first. This law grandfathered in 60,000 already existing chemicals without requiring them to be tested. Unfortunately, persistent deficiencies in TSCA have resulted in EPA being able to require testing on only around 200 of them. There are now over 80,000 chemicals on EPA’s chemical inventory.
Even if chemicals are shown to be dangerous, TSCA makes it nearly impossible for the EPA to restrict their use in consumer products. Because TSCA is so weak, even asbestos hasn’t been banned.
We need a stronger law to help us identify obesogens and other harmful chemicals before millions of us are exposed to them.
New legislation is under consideration that will help eliminate obesogens and other toxic chemicals: The Safe Chemicals Act of 2011. If passed, this legislation would require manufacturers to submit safety data on new chemicals—which would be made publicly available—before they are sold in products destined for consumers.
Some industry lobbyists are working to weaken or even kill the Safe Chemicals Act, but if enough voters speak up we can get it passed.
Tell your Senators now to support the Safe Chemicals Act to make sure that chemicals in the products we buy don't undermine our best efforts to stay healthy.
Hines EP, White SS, STanko JP, Gibbs-Flournoy EA, Lau C, Fenton SE. “Phenotypic dichotomy following developmental exposure to perfluorooctanoic acid (PFOA) in female CD-1 mice: Low doses induce elevated serum leptin and insulin, and overweight in mid-life.” Molecular and Cellular Endocrinology. 2009 May 25;304(1-2):97-105.
Jie Wei, Yi Lin, Yuanyuan Li, Chenjiang Ying, Jun Chen, Liquiong Song, Zhao Zou, Ziquan Lv, Wei Xia, Xi Chen, and Shunquing Xu. “Perinatal Exposure to Bisphenol A at Reference Dose Predisposes Offspring to Metabolic Syndrome in Adult Rats on a High-Fat Diet” Endocrinology May 17, 2011
Kirchner S, Kieu T, Chow C, Casey S, Blumberg B. “Prenatal exposure to the environmental obesogens tributyltin predisposes multipotent stem cells to become adipocytes.” Molecular Endocrinology. February 2010; 24(3) 526-539.
La Merrill, M. and Birnbaum, L. S., "Childhood Obesity and Environmental Chemicals." Mount Sinai Journal of Medicine: A Journal of Translational and Personalized Medicine, 2011. 78: 22–48.
Moss, Yeaton. “Young Children's Weight Trajectories and Associated Risk Factors: Results From the Early Childhood Longitudinal Study–Birth Cohort.” American Journal of Health Promotion: January/February 2011, Vol. 25, No. 3, pp. 190-198.
Stahlhut RW, van Wjingaarden E, Dye TD, Cook S, Swan SH. “Concentrations of urinary phthalate metabolites are associated with increased waist circumference and insulin resistance in adult US males.” Environmental Health Perspectives. September 2007; 115(9): A443.