What's in your soda?

An oil dispersant that might make you fat

New study links an additive to some soft drinks, laxatives and oil dispersants to obesity

By Brian Bienkowski, Environmental Health News

Stool softener, also pet laxative, and also a soda ingredient?

A chemical used in sodas and some laxatives for years assumed safe by federal health officials might make people more prone to obesity.

The chemical is used as a laxative and in sodas to help ingredients mix properly. It's also a major ingredient in Corexit, the dispersant applied by the millions of gallons in the Gulf of Mexico during the 2010 Deepwater Horizon disaster.

But the chemical, dicotyl sodium sulfoscuccinate, or DOSS, is a likely member of a family of chemicals contributing to obesity, researchers say in a study published today in the Environmental Health Perspectives journal.

That the chemical has been on the market for decades but is only now seen as possibly problematic offers further indictment of an inadequate federal chemical testing regime, critics say. And the new study bolsters evidence that chemicals in the environment play a role in growing obesity rates.

"These chemicals ... change the way you respond to calories," said Bruce Blumberg, a professor and researcher at the University of California who was not involved in the study.

DOSS has been around since the 1950s, used as a direct additive—put in food on purpose —or as an indirect additive in the packaging or processing of food, said Maricel Maffini, an independent consultant and scientist that studies chemical exposure.

A food ingredient database maintained by the Environmental Working Group, a non-profit health and environmental organization, lists DOSS as an ingredient in eight Flavor Air soft drink mixes, a Hawaiian Punch drink mix and Coca Cola’s Fanta.

But it could be in much more, said Maffini, formerly of the Natural Resources Defense Council. Small quantities can fall beneath reporting requirements, she said.

For example, the FDA lists DOSS as used in some breakfast cocoas. 

DOSS was declared “generally recognized as safe” in a 1998 petition to the U.S. Food and Drug Administration. The agency had “no questions” for Cytec Industries regarding their conclusion of DOSS’s safety in 1998 for use in carbonated drinks. 

Maffini said the “generally recognized as safe” distinction was intended for substances used for decades such as vinegars, oils and salts. “The loophole has been expanded greatly,” she said.

DOSS is also used as a laxative under multiple brand names including Colace and Docusate.

Marianna Naum, a spokesperson for the FDA, said the agency would review the new study but would not comment on the findings and what it means for the future of DOSS until an internal review is complete.

Medical University of South Carolina graduate student and co-lead author of the study, Alexis Temkin, said it’s unclear what levels of DOSS are in sodas or breakfast cocoa, but for laxatives a high dose for women would be about 500 milligrams. She and colleagues used doses about 2 to 10 times higher than that. However DOSS “could act completely different in a whole body compared to in a controlled setting in a lab,” she said.

The study comes as obesity continues to spread in the United States. About one-third of U.S. adults are obese, according to the Centers for Disease Control and Prevention, a number that has doubled over the past three decades.

Factors such as diet and lifestyle choices are undeniable but researchers continue to find surprising interactions between obesity and additives ubiquitous in food and consumer products. A study released earlier this year, for instance, linked bisphenol-A (BPA), an additive in plastics, canned food linings and thermal paper receipts, to obesity.

In the current study the researchers stumbled upon their findings almost by accident.

They were looking for non-lethal effects and any endocrine disruption impacts from exposure to the mixture crude oil plus Corexit, Temkin said. “We weren’t really familiar with DOSS before the study … it was sort of a needle in the haystack expedition.”

Oil dispersant concerns

Oil dispersant or soda ingredient?

DOSS is an effective oil dispersant because it separates oil and water, making it easier to pick up the oil. It is a major ingredient in Corexit dispersants, which were used in the Gulf of Mexico after the massive BP oil spill in 2010.

An estimated 1.8 million gallons of Corexit were sprayed to break down the oil.

It’s not the first link to health concerns for the dispersants. In April, University of Alabama at Birmingham researchers reported that one Corexit product used, Corexit EC9500A, can damage the cells in people’s lungs or aquatic creatures’ gills. 

There was "little potential for worker or public exposure to dispersants due to the extensive controls put in place, including extensive monitoring, by the federal government and BP," said BP spokesman Jason Ryan in an email.

Ryan also pointed out that long-term exposure to DOSS is much more likely to come from consumer products, such as flavored drinks and laxatives.

The U.S. EPA, and the Gulf Coast Ecosystem Restoration Council, comprised of multiple federal and local government agencies that have been working toward Gulf cleanup, all declined to comment on the new study.

Chemicals and obesity

Temkin and colleagues exposed mouse and human cells to different oil dispersant mixtures. DOSS increased genes associated with fat cells and activated receptors that spur the process of non-mature fat cells turning into mature fat cells.

“That a chemical causes more fat cells is concerning,” Blumberg said.

Temkin said it’s too early for the study to inform any kind of policy change for DOSS use, but that an important next step is to find a good way to measure how much of it people are actually exposed to.

“This is a strong study," said Michael Skinner, a professor and researcher at Washington State University who was not involved in the study. That strength comes in part because few studies have drilled down to see what the health effects could be from DOSS, he added.

Most concerning is exposure to such compounds as a fetus or at an early age, Skinner said. It’s not that such compounds simply make you fat, but they may increase your chances, and we can’t ignore that, he said.

“Any disease has two elements—first element is susceptibility to develop disease. That doesn’t mean you’ll get the disease, such as obesity,” Skinner said. “Now the second component is the actual trigger—what promotes the onset of obesity, such as diet and exercise.

“Lifestyle choices later in life are critical elements to promote obesity, but initial susceptibility had nothing to do with that.”

For questions or feedback about this piece, contact Brian Bienkowski at bbienkowski@ehn.org.