MUSC-led study links chemical in laxatives, drinks and more to possible metabolic and weight-related problems

A report published online today in the journal Scientific Reports suggests a chemical used in everything from cocoa to laxatives might be linked to metabolic and weight-related problems.

Dioctyl sodium sulfosuccinate, or DOSS, is classified as “generally recognized as safe” by the Food and Drug Administration. That means it doesn’t have to be listed in the ingredients as a food additive. But that hasn’t kept it from coming under scrutiny from some researchers as a possible “obesogen,” something that might promote obesity.

The study, led by scientists at the Medical University of South Carolina, is part of an effort to pinpoint which factors in our everyday lives may be causing us to eat more, move less and pack on the fat. The research was pre-clinical, meaning it was done in a lab and didn’t involve any testing on people. But the researchers say the animal model results are compelling and the next step will be clinical diagnostic and intervention trials.

MUSC College of Medicine professor Demetri Spyropoulos, Ph.D., was senior investigator on the study. It looked at the possible effects of DOSS on one group likely to be exposed to it: women taking laxatives that contain DOSS, such as Colace, while pregnant and breastfeeding. It found the women might gain extra pounds and their children might have multiple weight-related effects in the long term.

“We’re not arguing against the simple math,” Spyropoulos said. “You have a certain number of calories you take in and a certain number of calories that you burn. And if you take in more calories than you burn, you’re going to gain weight.”

What he is arguing is that DOSS might affect the body’s sense of hunger and what it does with the calories it takes in. “Obese people appear to be resistant to the appetite-suppressing effects of leptin. Our study shows that DOSS might be having the same effect. It might also change how the food coming into the body is handled. It will tell the body to put it into fat storage instead of making it available for energy use. So you’re hungrier sooner and you have less energy.”

According to the study, possible effects of DOSS exposure might include:

• Increased body mass, fat mass, fat percentage and reduced bone area.
• Altered circulating adipokine levels, meaning the body shows some of the hallmarks of obesity and metabolic syndrome.
• Chronic Inflammation. Obesity and type 2 diabetes are chronic inflammatory diseases.
• Changes in gene expression.
• Higher risk of glucose intolerance.
• Elevated circulating phospholipid patterns, meaning they showed changes similar to what you’d see in an obese person with diabetes caused by a long-term, high-fat diet.

This isn’t Spyropoulos’ first study to focus on DOSS. After the Deepwater Horizon oil spill in 2010, his team studied the environmental impact of the accident. The team was looking for any signs that that the spill and its cleanup might be releasing obesogens.

They took samples of the oil and dispersed oil from the spill site to their labs and zeroed in on DOSS, an ingredient in used to clean up the oil. Based on the way it acted when they added the chemical to cells grown in the lab, they flagged it as a possible obesogen. They published a report on their work in 2015 in the journal Environmental Health Perspectives.

The stool softener study published today was the next step, bringing it from cell culture to animal models. Alexis Temkin, Ph.D., the study’s first author, said understanding how exposure to chemicals during critical windows of development can impact chronic diseases is an important way to improve public health. “Our studies on DOSS are a piece of that larger body of work.” Temkin is now a toxicologist with the nonprofit Environmental Working Group.

In addition to some laxatives, products that may contain DOSS include:

• Air fresheners
• Cleaning supplies
• Cocoa
• Cosmetics
• Deodorants
• Ear drops
• Fruit juice drinks
• Milk
• Sodas

Spyropoulos said it’s important to keep pushing to find ways to keep our country’s weight problems from getting worse. “Right now, nearly 40 percent of Americans are obese or heavier, and in ten years it’s projected to be over 50 percent. Half of all Americans right now are either borderline diabetic or diabetic. It’s been called by many an epidemic.”

He said the risk for some people may be higher than others. “Our current work is on finding out which populations might be especially susceptible. We’re following a genetic argument, but there could be socioeconomic factors in that as well. That’s the nature of our studies.”

The DOSS study out today was funded by the Gulf of Mexico Research Initiative and the South Carolina Clinical and Translational Research Institute at MUSC. His team is currently funded by a Foundation for Research Development Award.

Spyropoulos said there’s a lot more work to be done. The new study is not definitive. “One thing was the dosage we used. We used on the high end of what women would have taken purely through Colace/docusate. Our argument is that this isn’t the only source of DOSS. There are dietary sources. If someone drinks a lot of soda, drinks a lot of milk, for example, they may be exposed to more DOSS.”