July 25, 2008 -- Chronic heartburn may alter the immune system and raise the risk of asthma, according to a new study that helps explain why so many people with asthma also suffer from gastroesophageal reflux disease (GERD).
Researchers say the link between asthma and GERD has been a mystery for years. Previous studies have shown that 50%-90% of people with asthma also suffer from gastric reflux, but until now the relationship between the two conditions was unclear.
The study shows that inhaling small amounts of stomach acid back up into the esophagus and lungs, a hallmark of GERD, slowly produces changes in the immune system that may lead to the development of asthma.
"This does not mean that everyone with GERD is going to develop asthma, by any means," researcher William Parker, assistant professor of surgery at Duke University Medical Center, says in a news release. "But it may mean that people with GERD may be more likely to develop asthma. If there is an upside to this, it is that developing GERD is something we can pretty much treat and control."
Asthma-GERD Link Explained
In the study, published in the European Journal of Clinical Investigation, researchers mimicked the effects of GERD in laboratory mice by inserting small amounts of gastric fluid into their lungs for eight weeks. They then compared how the immune systems of these mice responded to exposure to allergens, a key factor in the development of asthma, to the immune response of normal, healthy mice.
The results showed that the GERD mice responded very differently to allergens. Specifically, they developed an immune response similar to that found in people with asthma by releasing a specific type of infection-fighting T-cell. Healthy mice responded in a more balanced manner releasing two types of immune cells.
Researchers say rising rates of reflux and GERD may be driving increasing rates of asthma, but many of the risk factors behind this phenomenon may be modifiable.
They say people who already have GERD can minimize gastric reflux and reduce their risk of developing asthma by following these tips:
- Eat smaller meals
- Eat several hours before going to bed
- Raise the head of the bed a few inches
- Maintain a healthy weight
- Limit fatty foods, coffee, tea, caffeine, and alcohol because they can relax the esophageal sphincter and make reflux more likely.
"People should avoid the risk factors for GERD. We strongly believe that the rise in asthma, particularly among adults in the country, is in large measure due to lifestyle choices that can be changed," Parker says.