Persistent pollutant may promote obesity

December 1, 2008

Tributyltin, a ubiquitous pollutant that has a potent effect on gene activity, could be promoting obesity, according to an article in the December issue of BioScience. The chemical is used in antifouling paints for boats, as a wood and textile preservative, and as a pesticide on high-value food crops, among many other applications.

Tributyltin affects sensitive receptors in the cells of animals, from water fleas to humans, at very low concentrations—a thousand times lower than pollutants that are known to interfere with sexual development of wildlife species. Tributyltin and its relatives are highly toxic to mollusks, causing female snails to develop male sexual characteristics, and it bioaccumulates in fish and shellfish.

The harmful effects of the chemical on the liver and the nervous and immune systems in mammals are well known, but its powerful effects on the cellular components known as retinoid X receptors (RXRs) in a range of species are a recent discovery. When activated, RXRs can migrate into the nuclei of cells and switch on genes that cause the growth of fat storage cells and regulate whole body metabolism; compounds that affect a related receptor often associated with RXRs are now used to treat diabetes. RXRs are normally activated by signaling molecules found throughout the body.

The BioScience article, by Taisen Iguchi and Yoshinao Katsu, of the Graduate University for Advanced Studies in Japan, describes how RXRs and related receptors are also strongly activated by tributyltin and similar chemicals. Tributyltin impairs reproduction in water fleas through its effects on a receptor similar to the RXR. In addition, tributyltin causes the growth of excess fatty tissue in newborn mice exposed to it in utero. The effects of tributytin on RXR-like nuclear receptors might therefore be widespread throughout the animal kingdom.

The rise in obesity in humans over the past 40 years parallels the increased use of industrial chemicals over the same period. Iguchi and Katsu maintain that it is "plausible and provocative" to associate the obesity epidemic to chemical triggers present in the modern environment. Several other ubiquitous pollutants with strong biological effects, including environmental estrogens such as bisphenol A and nonylphenol, have been shown to stimulate the growth of fat storage cells in mice. The role that tributyltin and similar persistent pollutants may play in the obesity epidemic is now under scrutiny.

Source: American Institute of Biological Sciences

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3.7 / 5 (6) Dec 01, 2008
Makes you wonder if the "growth" in the past several decades was really worth the cost. Cheap energy, cheap food, and the general western lifestyle has brought many personal comforts, but we are left with a decimated environment and serious health problems. There is no free lunch, after all, it seems.
5 / 5 (1) Dec 01, 2008
"Free lunch"!?!....Hardy har....:) That was pretty funny, kerry. From the article==> "The rise in obesity in humans over the past 40 years parallels the increased use of industrial chemicals over the same period." .....That was a fairly ignorant statement. I'm sure obesity also parallels food intake, couch potato-ing, and internet traffic!
4.2 / 5 (5) Dec 01, 2008
Oh boy. Another excuse to take the blame off the person who is doing all the over-eating.

Eat more, weigh more. Eat less, weigh less. It's really pretty simple.
5 / 5 (2) Dec 01, 2008
Reading this comment "could be promoting obesity".
5 / 5 (1) Dec 01, 2008
Oh boy. Another excuse to take the blame off the person who is doing all the over-eating.

Eat more, weigh more. Eat less, weigh less. It's really pretty simple.

right on
...and if you want to eat more, exercise more.

(with regards to the few people out there with true hormone imbalance like hypothyroid - but there is treatment for that....)

I'll never forget the snippet of some TV program, where they featured a grossly overweight fellow (about to get stomach-banding). They said he got to where he was by eating the equivalent of "3 extra apples per week" above over his caloric requirements over his lifetime - made it sound so simple innocent, like oh if he didn't eat those couple of extra apples!

You have to take care of yourself. I know my caloric requirements have changed greatly over my life. When I start gaining weight, I cut back on high calorie stuff. Or workout a bit more :-)

5 / 5 (1) Dec 01, 2008
People eat more caloric foods (250 grams of sugar a day in the USA per person in average), they move less, so voila = they are getting heavier. No mysteries here, no virus, no toxins, no invisible powers. However, no doubt that we all have toxins in our bodies, and that they take a toll in our health.

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