There’s a new front in the battle of the bulge. Scientists think reprogramming microbes in our guts might be the secret to achieving a slim stomach.

Last year, researchers led by Vanderbilt University’s Sean S. Davies showed that mice fed bacteria genetically engineered to produce N-acylphosphatidylethanolamines, or NAPEs, stayed slimmer on a high-fat diet compared with mice that were fed different bacteria or mice that were given no bacteria at all. The effects lasted weeks after the researchers stopped feeding the rodents the genetically engineered bacteria.

NAPEs are produced naturally in the small intestine after food consumption and have been linked to feelings of fullness. “It appears that people who are obese don’t make enough of those compounds in response to food, and that may be one of the reasons they tend to overeat,” according to Davies.

There is, however, some debate as to whether the NAPEs themselves are responsible for suppressing appetites. Some scientists think N-acylethanolamines (NAEs), which are produced when enzymes in the small intestine break down NAPEs, actually curb hunger.

Davies reasoned he could answer this question by creating bacteria that produce NAEs and comparing them with his NAPE-producing bacteria. In normal mice, he found that both NAPE- and NAE-producing microbes had similar slimming effects. But in mice that lacked the enzyme that converts NAPEs to NAEs, only the NAE-producing bacteria kept the mice thin.

That result suggests that NAEs are really responsible for appetite suppression, and bacteria that produce them directly could be considered for curbing obesity, Davies said during a presentation Sunday at the American Chemical Society national meeting in Denver.

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Davies, who spoke during a session in the Division of Medicinal Chemistry, is quick to point out these are only proof-of-concept studies. There’s still much work to be done before people can use NAPE- or NAE-producing bacteria as a weight-control treatment. Even so, he said, the idea would be to sustainably give a drug of this sort constantly over time so there’s the best chance of treating a chronic condition. “Since bacteria are very persistent, we thought we could use that persistence and essentially create a bioreactor for the drug,” he says.