Can your fabric choices make you fat?

31 01 2013

We have all heard the stories of our “growing obesity epidemic” – especially in western nations. It’s an important national problem, and is partly responsible for our soaring health care costs. We often point to obesity as being caused by overeating, fast food, and/or sedentary lifestyles for those having a genetic predisposition to the disease. But the rates of obesity have escalated in such an exponential manner that the commonly held causes of obesity – overeating and inactivity – cannot explain the current obesity epidemic. A growing number of studies have suggested a new culprit: environmental rather than genetic causes.

Our world is different than it was 100 years ago. We have developed many synthetic organic and inorganic chemicals to make our lives easier – and used them in a fabulously wide range of products. In fact, you could say, as some do, that we’re living in a toxic soup of these chemicals. And those chemicals are changing us. Some of the chemicals changing us are called “endocrine disruptors” (which we discussed in last week’s post) since they interfere with the body’s hormone balance, which confuses the body. Initially, they caused concern because of their links to cancers and the malformation of sex organs. Those concerns continue, but the newest area of research is the impact that they have on fat storage.

It has been found that the developing organism (us!) is extremely sensitive to chemicals with estrogenic or endocrine disrupting activity and that exposure to these chemicals during critical stages of development may have permanent long-lasting consequences, some of which may not be expressed or detected until later in life.(1)

But back to obesity, which is what we’re concentrating on this week. (I know it’s difficult to stay on task, because these chemicals are synergistic, have multi-dimensional effects and often degrade into different substances altogether).

Nicholas Kristof, writing in the New York Times last weekend, talked about the results of a study which I found disturbing. Look at these two mice:

The only difference between these mice: The one at the top was exposed at birth to a tiny amount of an endocrine-disrupting chemical.  New York Times

The only difference between these mice: The one at the top was exposed at birth to a tiny amount of an endocrine-disrupting chemical. New York Times

According to Kristof, “they’re genetically the same, raised in the same lab and given the same food and chance to exercise. Yet the bottom one is svelte, while the other looks like, well, an American. The only difference is that the top one was exposed at birth to just one part per billion of an endocrine-disrupting chemical (2) . The brief exposure programmed the mouse to put on fat, and although there were no significant differences in caloric intake or expenditure, it continued to put on flab long after the chemical was gone.”

Bruce Blumberg, a developmental biologist at the University of California, Irvine, coined the term “obesogen” in a 2006 journal article to refer to chemicals that cause animals to store fat. Initially, this concept was highly controversial among obesity experts, but a growing number of peer-reviewed studies have confirmed his finding and identified some 20 substances as obesogens.

Manufacturers have already exploited obesogens by using them to fatten livestock, and by formulating pharmaceuticals to induce weight gain in grossly underweight patients. A study by Dr. Baillie-Hamilton presents the hypothesis that the current level of human exposure to these chemicals may have damaged many of the body’s natural weight-control mechanisms and that these effects, together with a wide range of additional, possibly synergistic, factors may play a significant role in the worldwide obesity epidemic.(3) And these changes continue generation after generation. It’s clear that the most important time for exposure is in utero and during childhood.(4)

The magazine Scientific American recently asked whether doctors should do more to warn pregnant women about certain chemicals.(5)  It cited a survey indicating that only 19% of doctors cautioned pregnant women about pesticides, only 8% about BPA (an endocrine disruptor in some plastics and receipts), and only 5% about phthalates (endocrine disruptors found in cosmetics and shampoos). Dr. Blumberg, the pioneer of the field, says he strongly recommends that people — especially children and women who are pregnant or may become pregnant — try to eat organic foods to reduce exposure to endocrine disruptors, and try to avoid using plastics to store food or water. “My daughter uses a stainless steel water bottle, and so do I,” he said.

Endocrine disruptors are found in fabrics – Greenpeace did a study of 141 clothing items purchased in 29 different countries from authorized retailers. Endocrine disruptors were found in 89 of the 141 articles tested. According to the report: “Overall, a variety of hazardous chemicals were detected within the broad range of high street fashion textile products analysed. These covered a diverse range of brands and countries of manufacture. These results indicate the ongoing – and in some cases widespread – use of hazardous chemicals in the manufacture of textile products openly marketed to consumers.”

It’s not clear whether most obesogens will do much to make an ordinary adult, even a pregnant woman, fatter (although one has been shown to do so). But what about our children, and their children? How does fabric processing impact my weight, or my child’s weight? Should I avoid certain processing chemicals in my own home?

The government made a tremendous impact on public health when it outlawed lead in gasoline. Now we need to make those same hard choices about doing without some of the things we’ve learned to like but which we know to be impacting our health. Support the Safe Chemicals Act and spread the word. This is too important to ignore.

[1] Newbold, R. R., Padilla-Banks, E., Snyder, R. J. and Jefferson, W. N. (2005), Developmental exposure to estrogenic compounds and obesity. Birth Defects Research Part A: Clinical and Molecular Teratology, 73: 478–480. doi: 10.1002/bdra.20147

[2] Newbold, R. R., Padilla-Banks, E., Snyder, R. J. and Jefferson, W. N. (2005), Developmental exposure to estrogenic compounds and obesity. Birth Defects Research Part A: Clinical and Molecular Teratology, 73: 478–480. doi: 10.1002/bdra.20147

[3] Baillie-Hamilton, PF, “Chemical toxins: a hypothesis to explain the global obesity epidemic”, Journal of Alternative and Complementary Medicine, April 2002,

[4] Blumberg, Bruce et al, “Transgenerational Inheritance of Increased Fat Depot Size, Stem Cell Reprogramming, and Hepatic Steatosis Elicited by Prenatal Obesogen Tributyltin in Mice”, Environmental Health Perspectives, January 15, 2013.

[5] Kay, Jane, “Should Doctors Warn Pregnant Women about Environmental Risks?”, Scientific American, December 10, 2012.

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