All humans have gas in their gastrointestinal tracts. The National Institute of Diabetes and Digestive and Kidney Diseases reports that humans produce approximately one to four pints of gas daily. Odorless gases predominate in the intestine, including hydrogen, oxygen, nitrogen, carbon dioxide and methane. Trace amounts of skatole, indole and hydrogen sulfide produced in the colon have a pungent unpleasant odor. Common causes of increased flatulence are predominantly diet-related.
Raffinose
Beans, broccoli, cauliflower, cabbage, brussels sprouts, asparagus and some whole grains contain raffinose, a complex sugar. Raffinose remains largely undigested in the small intestine. Bacteria in the colon ferment raffinose, producing gas. Consumption of large quantities of raffinose-containing foods increases intestinal gas production, notes the American Gastroenterological Association. Over-the-counter medications containing enzymes to help digest raffinose in the small intestine may lead to less gas production in the colon.
Fructose
Fructose is a natural sugar found in prunes, watermelon, cantaloupe, grapes, dates, figs, coconut, pears, honey, maple syrup, molasses, onions, leeks, artichokes and wheat. High-fructose corn syrup is also commonly added as a sweetener to sodas, fruit juices, commercial cakes and cookies and other processed foods. InteliHealth.com, a health information website produced in collaboration with the faculty of Harvard Medical School, reports that excessive fructose in the diet can overwhelm the small intestine's ability to digest and absorb the sugar. Bacteria in the colon break down undigested fructose, causing increased intestinal gas.
Sugar Alcohols
Sugar alcohols are a form of sugar that occurs naturally in corn, raspberries, strawberries, pears, peaches, carrots, olives, sweet potatoes and pineapples. Sugar alcohols such as sorbitol, isomalt, mannitol, lactitol and xylitol are also used as sweeteners in many processed foods, especially those marketed as "diet" or low-calorie foods. Information provided by Yale-New Haven Hospital explains that the small intestine digests sugar alcohols slowly. When large quantities of sugar alcohols are consumed, significant quantities reach the colon undigested. The colon bacteria ferment the undigested sugar alcohols, leading to increased intestinal gas and possibly diarrhea.
Lactose
Milk contains lactose, a sugar normally broken down by the enzyme lactase in the small intestine. Children typically possess high concentrations of intestinal lactase. The amount of lactase produced often decreases as people pass from childhood to adulthood. Markedly reduced lactase production may lead to intestinal gas, bloating and diarrhea associated with the consumption of dairy products. This condition, known as lactose intolerance, is a frequent cause of intestinal gas, notes the American Gastroenterological Association. Over-the-counter lactase supplements and dairy products with lactase added can help alleviate symptoms for those with significant lactose intolerance.
