With more than a third of US adults currently obese, researchers are on the hunt for new strategies that could help prevent weight gain. Now, a team from Purdue University in West Lafayette, IN, suggests that increasing activity in a neural pathway from the gut to the brain could reduce food consumption during a meal and help regulate body weight.
Edward Fox, a professor of psychological sciences at Purdue, and co-author Jessica Biddinger, a graduate of the university, recently published their findings in The Journal of Neuroscience.
To reach their findings, the team analyzed a mouse model with a knockout brain-derived neurotrophic factor (BDNF) gene, alongside control mice. The absence of a BDNF gene, the researchers say, leads to reduced levels of BDNF in the intestines.
They explain that BDNF plays a role in controlling the development of sensory pathways in the vagus nerve - the nerve that extends from the brain stem to the gut.
The vagus nerve sends sensory information from the gastrointestinal tract to the brain, detailing the types of nutrients in the gut. It also sends sensory information to stomach muscles when we eat.
Nerve fiber formation increased
The team was surprised to find that the mice with a knockout BDNF gene experienced an increase in vagal sensory innervation in the gastrointestinal tract. In other words, there was an increase in nerve fiber formation. In addition, these mice ate small meals and spent less time eating them.
Explaining the reason behind these findings, Fox says it is likely that as a result of the increased nerve fiber formation, signaling from the gut to the brain also increased and told the brain that the stomach was full.
Based on their study results, the researchers believe that it could be possible to stimulate the vagus nerve in humans in order to reduce food consumption.
Electrical vagus nerve stimulation is already used in patients with epilepsy or depression who fail to respond to medications. Fox notes that the procedure has been linked to reduced body weight in some patients, and that the team's research indicates that this may be due to eating smaller meals, rather than experiencing a boost in metabolism or eating fewer meals.
But Fox believes that although treating people so they will eat smaller meals may help regulate weight, that alone may not be enough to tackle obesity:
"With lack of exercise and strong environmental factors, such as a wide variety of great-tasting foods, overeating and obesity may be too much to overcome by reducing meal size on its own.
But if we can use this model and similar ones we have developed involving other genes to understand how vagal sensory information gets integrated with the brain areas that control eating, we can better address how meal behavior and other factors interact to control our body weight."
Medical News Today recently reported on a study by researchers from Vanderbilt University in Nashville, TN, detailing the discovery of a bacteria that produces a "therapeutic compound" in the gut to stop weight gain, paving the way for a probiotic that could prevent obesity.