Intestinal Gas (Belching, Bloating, Flatulence) (cont.)
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Intestinal gas facts
- What causes belching?
- What causes bloating?
- What causes flatulence (gas)?
- What are the causes of intermittent abdominal bloating/distention?
- How are belching, bloating/distention, and flatulence evaluated?
- How is excessive intestinal gas treated?
- What's new in intestinal gas?
How is excessive intestinal gas treated?
The treatment of excessive intestinal gas depends on the cause.
- If there is maldigestion of specific sugars-lactose, sorbitol, or fructose--the offending sugars can be eliminated from the diet.
- In the case of lactose in milk, an alternative treatment is available. Enzymes that are similar to intestinal lactase can be added to the milk in order to break down the lactose prior to its ingestion so that it can be absorbed normally. Some people find that yogurt, in which the lactose has been broken down partially by bacteria, produces less gas than milk.
- There also are certain types of vegetables and fruits that contain types of starches that are poorly digested by people but well digested by bacteria. These include beans, lentils, cabbage, Brussels sprouts, onions, carrots, apricots, and prunes. Reducing the intake of these vegetables and fruits, as well as foods made from whole grains, should reduce gas and flatulence. However, the list of gas-producing foods is rather long, and it may be difficult to eliminate them all without severely restricting the diet.
- When maldigestion is due to pancreatic insufficiency, then supplemental pancreatic enzymes can be ingested with meals to replace the missing enzymes.
- If maldigestion and/or malabsorption is caused by disease of the intestinal lining, the specific disease must be identified, most commonly through a small bowel biopsy. Then, treatment can be targeted for that condition. For example, if celiac disease is found on the biopsy, a gluten-free diet can be started.
- An interesting form of treatment for excessive gas is alpha-D-galactosidase, an enzyme that is produced by a mold. This enzyme, commercially available as Beano, is consumed as either a liquid or tablet with meals. This enzyme is able to break down some of the difficult-to-digest polysaccharides in vegetables so that they may be absorbed. This prevents them from reaching the colonic bacteria and causing unnecessary production of gas. Beano has been shown to be effective in decreasing the amount of intestinal gas.
- Two other types of treatment have been promoted for the treatment of gas; simethicone (Phazyme; Flatulex; Mylicon; Gas-X; Mylanta Gas) and activated charcoal. It is unclear if simethicone has an effect on gas in the stomach. However, it has no effect on the formation of gas in the colon. Moreover, in the stomach, simethicone would be expected only to affect swallowed air, which, as previously mentioned, is an uncommon cause of excessive intestinal gas. Nevertheless, some individuals are convinced that simethicone helps them. Activated charcoal has been shown to reduce the formation of gas in the colon, though the way in which it does so is unknown.
- If there is a physical obstruction to the emptying of the stomach or passage of food, liquid, and gas through the small intestine, then surgical correction of the obstruction is required. If the obstruction is functional, medications that promote activity of the muscles of the stomach and small intestine are given. Examples of these medicines are erythromycin or metoclopramide (Reglan).
- Bacterial overgrowth of the small bowel usually is treated with antibiotics. However, this treatment is frequently only temporarily effective or not effective at all. When antibiotics provide only a temporary benefit, it may be necessary to treat patients intermittently or even continuously with antibiotics. If antibiotics are not effective, probiotics (for example, lactobacillus) or prebiotics can be tried although their use in bacterial overgrowth has not been studied. This condition may be difficult to treat.
What's new in intestinal gas?
A recent study has shed additional light on the role of intestinal gas and the way in which it causes symptoms. Investigators studied 30 patients whose primary complaint was flatulence (although they also had other complaints such as abdominal bloating, distension and/or discomfort), and 20 healthy people (controls) without issues related to gas. The investigators studied the patients' and controls' production of gas and symptoms on their normal (basal) diet, during and following a standard meal, and during and following a meal that contained foods known to cause more gas (flatulent diet). During the basal period, not surprisingly, the patients had more symptoms than the controls and evacuated gas (farted) more often than controls (22 vs 7 times during the day). Interestingly, however, the patients and controls produced the same total volume of gas following the standard meal. This would suggest that the patients were NOT producing more gas than the controls. Two explanations for these observations would be 1) that the basal diet contained more gas-producing foods, or 2) that patients were more sensitive to gas, i.e., they developed more discomfort producing the same amount of gas as controls (farting more frequently, but with less gas per fart).
On the flatulogenic diet, the controls developed some symptoms, but the patients, not surprisingly, developed worse symptoms. The number of farts increased for both patients and controls but more so for the patients, (44 vs 22 farts, respectively). Nevertheless, the total amount of gas that was produced on the flatulogenic diet was the same for controls and patients. This supported the probability that patients were more sensitive to gas, i.e., they developed more symptoms, and farted more even though they were producing the same amount of gas as controls.
The observations made in this study add considerably to our understanding of intestinal gas and the mechanism whereby gas causes symptoms. In the group of patients that was studied, the symptoms were caused by an abnormal sensitivity to gas and not to the production of more gas. It is important to recognize, however, that although this may be the mechanism for production of symptoms in this group of patients, there may be other explanations or contributing factors in other patients with symptoms and flatulence. For example and as explained previously, some patients may retain more gas in the abdomen due to problems with motility of the intestinal muscles leading to intestinal distention and discomfort. Some patients may be on a flatulogenic diet without realizing it, and some patients may indeed be producing more gas than others on the same diet.
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Houghton , L. et al. “Relationship of Abdominal Bloating to Distention in Irritable Bowel Syndrome and Effect of Bowel Habit.” Gastroenterology; July 2005. Vol. 131, Issue 4, p1003–1010.
Manichanh, C. et al. Anal gas evacuation and colonic microbiota in patients with flatulence: effect of diet. Gut 2014;63:401-408.
Salvioli , B. et al. "Origin of gas retention and symptoms in patients with bloating." Gastroenterology; March 2005. Vol. 128, Issue 3, p574–579.
UpToDate. Gas and bloating (Beyond the Basics).
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