Quieting intestinal gas

OTCs Today

Mary Warner

Intestinal gas is extremely common, as well as extremely annoying. It can be caused by swallowing air while eating, chewing gum, or drinking through a straw; bacteria in the large intestine breaking down undigested carbohydrates; certain foods that contain fermentable carbohydrates; and digestive conditions such as celiac disease and lactose intolerance. Fortunately, several OTC products are available to manage intestinal gas.

The most frequent symptoms of excess intestinal gas are belching, bloating, and flatulence. When recommending appropriate nonprescription treatment, it is important to differentiate between acute, temporary symptoms versus those that may indicate a chronic GI disorder such as irritable bowel syndrome, lactose intolerance, or celiac disease.

Avoiding intestinal gas

Gas is a normal part of the digestive process, but when excessive gas gets trapped in the GI tract, it can cause cramping, bloating, burping, flatulence—and sometimes embarrassment. To avoid excess intestinal gas, dietary adjustments (identifying and reducing or eliminating foods that trigger gas), changing eating habits (eating slowly and chewing thoroughly), and lifestyle changes such as regular exercise and managing stress can be helpful.

Rating foods by their potential to cause intestinal gas symptoms is difficult, but clinical experience suggests that certain foods are generally more problematic than others. Common gas-producing foods include vegetables such as cauliflower, broccoli, and beans; fruits such as prunes and apricots; and whole grains and brown rice. Carbonated beverages can also contribute to gas formation in the intestines. In addition, people who are lactose intolerant should avoid dairy products and other foods containing milk or milk-derived carbohydrates. Products containing milk-derived protein (e.g., whey powder, caseinate, and other lactoproteins) do not cause lactose-associated GI symptoms.

Some medications can also cause intestinal gas, including those that affect food absorption and metabolism (e.g., a-glucosidase inhibitors, metformin, and lipase inhibitors) and those that affect GI motility (e.g., opioids, anticholinergics, and calcium channel blockers).

The odor of passed gas is caused by sulfur-based gases (i.e., hydrogen sulfide, methanethiol, and dimethyl sulfide) and may be worsened by eating sulfate-containing foods, such as cruciferous vegetables (e.g., broccoli and cabbage), breads and beers containing sulfate additives, and proteins with a high content of the sulfur-containing amino acids methionine and cysteine (e.g., eggs, macadamia nuts, peanuts, pistachio nuts, and red meats). Avoiding these foods can mitigate the flatulence odor and reduce possible embarrassment.

Managing intestinal gas

Anti-gas products alleviate symptoms by reducing the gas bubbles in the digestive tract, breaking down poorly digested carbohydrates, or improving the balance of intestinal microbiota. Three ingredients are commonly used in anti-gas products: simethicone, a-galactosidase, and activated charcoal.

Simethicone, a mixture of inert silicon polymers, acts in the stomach and intestine to reduce the surface tension of gas bubbles, causing them to break or coalesce and allowing them to be eliminated more easily by belching or passing gas. Many OTC products contain a combination of simethicone and antacids, and single-ingredient products usually contain a higher concentration of simethicone than combination products. Because simethicone is not absorbed within the GI tract, it has no known systemic adverse effect, and its safety has been well documented.

a-galactosidase, an enzyme derived from Aspergillus niger, hydrolyzes oligosaccharides into their components so they can be metabolized by colonic bacteria to increase digestion and prevent the formation of gas. Because high-fiber foods contain large amounts of oligosaccharides, a-galactosidase is recommended for prevention of excessive intestinal gas production associated with high-fiber diets or consumption of foods that contain oligosaccharides. Patients with galactosemia or patients allergic to molds should not use a-galactosidase.

Activated charcoal is sometimes promoted for relief of intestinal gas. However, FDA classifies activated charcoal as “lacking substantial evidence of efficacy” as an antiflatulent or digestive aid. The proposed antiflatulent properties of activated charcoal are related to the adsorbent effects of the substance and its potential to facilitate the elimination of intestinal gas from the GI tract. It has also been suggested that activated charcoal can eliminate malodorous, sulfur-based gases.

What to tell your patients

Encourage patients to keep a food journal to help identify problematic items in order to avoid them. Patients who experience new or worsening digestive symptoms, including gas or bloating, should consult their health care provider to ensure that their symptoms are not a result of other GI diseases.

For further information, see the section on Intestinal Gas in APhA’s Handbook of Nonprescription Drugs, available in print on pharmacist.com or online in APhA OTC at pharmacylibrary.com. ■