A crew sprays a solution containing DDT in an alley in Santa Monica in 1948. Photo: Los Angeles Times Archive

By Tony Barboza
23 October 2013

(Los Angeles Times) – Exposure to the pesticide DDT could be playing a role in high rates of obesity three generations later, a new study says.

Scientists injected pregnant rats with DDT and found no change in their levels of obesity or their offspring. But by the third generation, more than half of the rats (think of them as the great-grandchildren) showed dramatically higher levels of fat and weight gain, even though they were never exposed to the pesticide themselves.

"Here is an ancestral exposure in your great-grandmother, which is passed on to you and you’re going to pass on to your grandchildren," said Michael Skinner, a professor of biological sciences at Washington State University who led the research published in the journal BMC Medicine.

At work is a disease inheritance phenomenon discovered more than 15 years ago, Skinner said.

A series of experiments on lab rats found that chemicals known as endocrine disruptors, including fungicides, dioxin and bisphenol-A, or BPA, can alter the molecular processes around their DNA without changing its sequence, Skinner said.

The contaminants can turn genes on or off and be passed on to descendants generations down the line, leading them to develop conditions like kidney disease, ovarian disease or obesity.

"We’ve all been taught that the primary way for us to inherit things from our parents is genetics," Skinner said. "This is a totally new concept for how we inherit things from our ancestors."

Though the study makes no conclusions about the risk to humans, Skinner said it should give pause to those advocating the use of DDT to combat malaria more than 50 years after Rachel Carson’s book Silent Spring brought attention to the pesticide’s lasting damage to the environment. [more]

Ancestors' exposure to DDT may contribute to obesity, study says


  1. Anonymous said...

    DD will post anything that sounds like bad news, apparently. From a single study of rats INJECTED with DDT, the article asks us to question whether it was worth saving hundreds of millions of lives with DDT because you "may"--"MAY"--get fat because someone sprayed DDT in your grandma's backyard.  

  2. Jim said...

    This study is interesting, because it provides the first credible causation for the observed upward trends in obesity (Graph of the Day: Progression of Obesity and Overweight Rates in Seven OECD countries). Attributing these trends to an epigenetic effect is quite novel and should stimulate more research in this area.  

  3. Michael said...

    No, Jim. The study is garbage. It extrapolates from rats injected with DDT to humans who may or may not have been exposed. The article makes the appalling suggestion that hundreds of millions of people saved from malaria by DDT may not have been worth it. This is disgusting.


  4. Jim said...

    Glancing over the study, and having no particular expertise in biology, it looks like a reasonable piece of research: Ancestral dichlorodiphenyltrichloroethane (DDT) exposure promotes epigenetic transgenerational inheritance of obesity. It's possible that DDT saved millions of lives and also caused obesity through an epigenetic effect.

    The study concludes:

    "Although the number of lives saved from malaria is significant, the long-term health and economic effects on survivors and subsequent generations also need to be considered. Since other options exist with less toxic shorter half-life pesticides, a more careful risk/benefit consideration of the use of DDT is now needed."

    This is a reasonable statement of cost-benefit analysis, which strikes me as more practical than disgusting.  


Blog Template by Adam Every . Sponsored by Business Web Hosting Reviews