Programmed to be Fat?
We all know that being overweight is the result of various factors – diet, exercise, lifestyle choices, “bad genes”… but a documentary recently aired on CBC (a Canadian TV network), “Programmed to be Fat”, brought to light the links between obesity and common chemicals in products we use every day. Some of these chemicals (listed below) are found in plastics, food packaging, pesticides, metal cans, flame retardants and cosmetics.
Currently, there is a lot of research out there which clearly explains that obesity problems are partially due to too much caloric intake and too little energy output. However, research into obesogens suggests that common chemicals may be creating more fat cells in our bodies and allowing existing ones to get larger, by altering our hormones.
The scariest part is that being overweight may have been hardwired into our systems from when we were just fetuses. Professor Bruce Blumberg from the University of California, and researcher on how obesogens can trigger increases in body fat says, “When animals are exposed prenatally to these chemicals, their metabolism is reprogrammed so that even if they are never exposed again in their lives, they gain weight.”
These obesogens may be telling a developing fetus in the womb to make more fat cells – setting it up for the rest of its life to be “programmed” for weight gain and retention.
Bruce Mohun, director of the documentary which aired on CBC on January 12th in Canada, had a one-on-one with the Star:
“How would a mother’s exposure to these chemicals during pregnancy affect the child’s future obesity?
Essentially these endocrine-disrupting chemicals, which mimic hormones, get into the mother’s body and into the fetus through the placenta and tweak the system a wee bit. Receptors receive the hormones which tell how fat or skinny the child should be depending on the environment they’ll be born into, but these receptors are not very precise. They acknowledge anything that looks like a hormone.
What about exposure after birth, does that add to a tendency to gain weight?
These hormone-mimicking chemicals are still capable of affecting the receptors and how the endocrine system works until the end of puberty. They can change how much fat the body stores and how many fat cells are in the body.
The researchers you interviewed devised animal studies to look at these chemicals and obesity. What did these mice studies show?
If you give pregnant mice tiny amounts of endocrine-disrupting chemicals, like two parts per billion, their offspring will be fatter than control mice. It was found time and time again.
How solid is this science? Is this still all theory?
Canadian researcher Alison Holloway from McMaster said it best: ‘Is it plausible that these chemicals are causing obesity? Absolutely. Has it been shown unequivocally? No.’
The key players are sure enough that something is going on here that something needs to be done. If we don’t absolutely need these chemicals we should get rid of them.
You say in the documentary that the chemical industry hasn’t been able to reproduce the results.
There seems to be a divide. If you work in industry supported by the chemical companies your studies don’t show the same results as those done by the academic researchers.
The hormone disruption occurs with the tiniest doses, but not the large ones. How could that be?
It’s a gene effect. These systems are set up to respond to very small signals from hormones. The receptors expect just a few hormones. If they get too many signals, if they’re bombarded with endocrine-disruptors, another gene comes into play. It recognizes these aren’t legitimate signals and shuts down the receptors.
Does this mean no matter how hard you diet and exercise, you can’t lose weight?
No. Environmental chemicals would be only one of many reasons we might be overweight. They might exacerbate the effects of overeating and not exercising.
In the whole obesity puzzle, how big a role do environmental chemicals play?
I asked all the researchers that question and they have no idea. They don’t know enough about it yet.
Pregnant women already have a lot to worry about. How concerned should they be? What should they do?
The same things they’re doing to avoid other possible developmental effects from environmental chemicals: try not to handle store receipts, which may contain bisphenol A; avoid food in cans and processed foods; don’t microwave plastic food containers; don’t use plastic water bottles.”
Not only might we be destined to be overweight from the time we are conceived, but we are also eating lots of junk as adults – adding further insult to injury.
“The reality is both are happening,” says Professor Blumberg. “We’re being exposed to obesogens and eating bad food. So it’s a double impact. In the US we’re cutting fats yet obesity has doubled. We’re doing what we’re supposed to be doing yet we are getting fatter and fatter.”
In the U.S., while we have tons of advertising for unhealthy processed foods, a government-sponsored workshop in February of 2011 by the National Institute of Environmental Health Sciences recruited over 135 scientists to evaluate the science linking obesity to these six common chemicals:
1. Arsenic and other metals
2. Bisphenol A
3. Organotins and phthalates
4. Nicotine
5. Pesticides
6. Persistent organic pollutants
There is “good, qualitative evidence” which links maternal smoking, arsenic, and persistent organic pollutants (POPS) exposure to obesity and diabetes, according to workshop chair Michael Gallo, Ph.D.
Putting the scientific evidence aside, it makes common sense that chemicals that aren’t found naturally in our bodies would impact us in some way. Now that we are seeing these impacts are probably negative, it pays to take a few minutes to learn about them, where they’re found, and take action to avoid ingesting them –especially if you are pregnant.
Photo Credits:
Flickr/Ellipsis Sundays