For those suffering from heartburn, a piece of chocolate may start as a joy to the tongue, but can end with a raging fire in the stomach.
But there may be new hope for those suffering chocolate-lovers.
A new study presented on May 23rd at the Digestive diseases week in Atlanta, US, revealed how chocolate irritates the digestive tract of those who suffer with chronic heartburn - also known as gastro-oesophageal reflux disease, or GERD.
"We demonstrated that chocolate induces GERD symptoms by compromising the ability of the lower oesophageal sphincter to prevent the stomach acids from creeping back up the oesophagus," says Chung Owyang, chief of the University of Michigan Division of Gastroenterology and professor of internal medicine in the University of Michigan Medical School.
"We also found that a medication commonly used for nausea may ease these painful symptoms," adds Owyang, the study's principal investigator.
In the study, seven GERD patients underwent a series of tests to measure acidity in the oesophagus and how long it took the acidity to go back to normal levels.
Researchers also determined the pressure of the lower oesophageal sphincter, located at the junction between the stomach and the oesophagus.
The researchers found that chocolate significantly increased the number of reflux events and the acid exposure time in the oesophagus for the seven patients.
"We found that the chocolate causes a large amount of serotonin to be released from the cells in the intestines," says Wei Ming Sun, Ph.D., research scientist, University of Michigan Department of Internal Medicine.
"The serotonin causes the lower oesophageal sphincter to relax.
The relaxation means the 'door' between the oesophagus and stomach is opened and acid is allowed to flow back up to the oesophagus."
After documenting the effects, patients were given granisetron, which is used against nausea.
Granisetron was shown in earlier University of Michigan studies to reduce the effects of chocolate on patients who did not have GERD.
"When the patients with GERD took the granisetron, which is a serotonin blocker, there was a significant decrease in the numbers of reflux events, the acid exposure time and the acid clearance time," Owyang says.
This novel approach may provide alternative effective methods for the treatment of GERD without inhibiting normal acid secretion, which is important to digestion and control of bacterial growth.
Source: University of Michigan Health System