February 24, 2006
Weakly acidic reflux can also cause heartburn
By Anne Harding
NEW YORK (Reuters Health) - Reflux doesn't have to be
extremely acidic in order to give you that burning feeling, a
new study shows.
In fact, burping can result in heartburn even when no
liquid accompanies the gas up the esophagus, Dutch researchers
It remains unclear why reflux episodes don't always cause
heartburn, Dr. A J. Bredenoord of St. Antonius Hospital in
Nieuwegein, the Netherlands, and colleagues note in a report in
the journal Gut.
To investigate, they monitored 32 patients with
gastroesophageal reflux disease, or GERD, symptoms for 24 hours
using traditional pH testing as well as a technique called
Impedance allows researchers to evaluate how far reflux
extends up from the stomach, measure the volume of reflux, and
evaluate acidity with greater precision. "It's a completely new
way of looking at reflux," Bredenoord said.
All of the study subjects had stopped taking
A total of 1,807 episodes of reflux occurred, with 203
causing symptoms. Episodes that caused symptoms showed a larger
increase in acidity within the esophagus, more acidity, and
extended further up the esophagus. The volume of reflux in
heartburn-causing episodes was larger than for those that
caused no symptoms, while the liquid also took longer to clear
from the esophagus.
Nearly 15 percent of reflux episodes were caused by more
weakly acidic reflux material.
The researchers also identified 426 gas-only reflux
episodes, 12 of which caused symptoms. Symptoms were more
likely with gas reflux if they were accompanied by a rise in
The findings show, Bredenoord said, that "if you only focus
on looking at whether these symptoms are related to acid, you
will certainly miss a few patients who symptoms are also
related to weakly acid reflux." And volume of reflux, as well
as its acidity, plays a role in whether it causes symptoms, he
He points out that some drug companies are developing
medications designed to reduce the number of reflux episodes,
rather than targeting acidity, as all currently available GERD
drugs do. This could be helpful for the minority of patients
whose symptoms are due to more weakly acid reflux, he said.
Also, Bredenoord said, instruments for measuring impedance
have been approved in both the United States and Europe, and
will be more effective for evaluating GERD patients and
monitoring treatment effectiveness than pH alone, without
causing patients' additional discomfort.
SOURCE: Gut, March 2006.