KNOWING when to stop eating is a battle waged between your body and your brain.
Now scientists have found that a stomach receptor that detects capsaicin – the molecule in chili that delivers the ‘hot’ sensation – could be the answer to prevent overeating.
Their research shows that disrupted activity of the capsaicin receptor can explain the slowed feeling of fullness that happens in obesity.
“Receptors for capsaicin are called TRPV1, and are located on nerve endings in the stomach,” said study author Associate Professor Amanda Page, who is based at the South Australian Health and Medical Research Institute (SAHMRI).
“As the stomach stretches when you eat a meal, the nerves become activated through these receptors, and tell the brain you’re full.”
“Our research shows that the TRPV1 receptor is disrupted by obesity due to a high fat diet,” said Professor Page.
To reach their conclusions, Professor Page and her colleagues compared normal mice with mice who did not express the gene for the TRPV1 receptor.
In mice that ate a normal diet, knocking out the receptor lead to an increase in food intake.
Mice that became obese due to a high fat diet showed no difference in how much they ate and the response of their stomach nerves, regardless of whether or not they expressed the TRPV1 receptor.
“It suggests the TRPV1 channel is mediating satiety, or the sensation of feeling full,” Professor Page said.
So given that it’s capsaicin that has activity via TRPV1, could we all simply consume more chili to ensure we don’t overeat?
“Well, maybe – if you can tolerate chili,” said Professor Page.
“Or perhaps we could develop a capsulated form of capsaicin to target the TRPV1 receptors in the stomach without having to experience the mouth heat.”
To develop this science further, Professor Page and her colleagues are looking in more detail at how obesity changes the way that TRPV1 receptors function.
“We think there could be an interaction between TRPV1 and other receptors in the stomach,” she said.
Dr Stephen Kentish from the University of Adelaide’s School of Medicine was also an author on the study.
“It’s exciting that we now know more about the TRPV1 receptor pathway and that the consumption of capsaicin may be able to prevent overeating through an action on nerves in the stomach,” he said.
This research was funded by the Blue Gum bequest, Royal Adelaide Hospital, and published in the journal PLOS ONE.