High-Fiber Diets Can Cause Digestive Gases

Everyone in the family, from house pets to doddering grandparents, does it. And almost everybody giggles about it - at least privately.

Although Pumba the wart hog in “The Lion King” does it with impunity, most of us find the process of expelling digestive gases from the lower bowel an embarrassing act, especially in public. Despite the fact that it is a natural bodily function closely associated with the food we eat, flatulence seldom is discussed in a serious way.

Socially acceptable or not, we all should understand it, says Dr. Ali Keshavarzian, a professor of medicine and pharmacology and director of the Gastrointestinal Motility Clinic at Loyola University Medical Center in Maywood, Ill.

“The first reaction many people have is that no one has the problem but them,” says Keshavarzian, an authority on gastrointestinal and bowel disease. “But it is mainly that no one wants to talk about it. The fact is, all of us have gas in our colon, which eventually must be expelled.”

Contrary to what many people believe, less than a third of our bowel gas comes from foods we eat. About 70 percent is from swallowed air that first passes through the stomach and small intestine. In fact, gas often is an indication we are eating more healthfully, that we are getting more complex carbohydrates and fiber, Keshavarzian says.

Here’s a simple explanation of how the process works:

The carbohydrates, fats and protein we eat in foods become a kind of gastric soup in the stomach as digestive acids begin attacking them. This mixture then passes into the small intestine.

Along with food, we also swallow quantities of air, some of which returns back up the esophagus in the form of burps or belches.

In the small intestine, pancreatic enzymes and intestinal secretions break down the fats, proteins and carbohydrates so they can be absorbed through the intestinal walls and eventually enter the bloodstream and feed the body. Fats, proteins and simple carbohydrates, such as sugar, are fully absorbed here.

The more complex carbohydrates, along with dietary fibers (the textural components of fruits, vegetables and grains, for instance) pass into the large intestine. There they are attacked by millions of resident bacteria, sometimes as many as 400 different kinds, that cause further fermentation.

It is this process that also generates relatively large quantities of hydrogen, carbon dioxide and a few other gases - anywhere from about a half-quart to 2-1/2 quarts in volume.

The more fiber we eat, the more gas we produce, at least for a while.

“Those who complain of gas pain and excess flatulence may be getting it because of too rapid change in their diet, often because they are moving from a low-fiber to a high-fiber diet,” Keshavarzian says. “A radical change can produce much more gas than normal until the bacteria in the lower bowel adjust to the added fiber.”

Adding fiber to a diet more gradually usually solves the problem, he says.

Excess gas usually stems from natural dietary changes, but sometimes gas pain can indicate a pathological disease or a blockage of the intestine.

Also, a significant number of people, mostly non-white, have trouble producing the enzyme that digests lactose, a prominent carbohydrate in dairy products; consuming too much milk or ice cream may cause those with lactose intolerance to generate more gas.

Foods high in complex carbohydrates and fiber - such as beans, cruciferous vegetables, onions, garlic and fresh fruits - traditionally are associated with increases in gas, yet they also are the foods highly recommended as a part of the cancer-preventive regimen of eating five servings of fruits and vegetables a day.

Gas also may result from more processed foods and medicines, such as antacids, sugar substitutes and foods with fat-replacers, which often are made from complex carbohydrates.

Beano and Be Sure are supplements that purport to reduce the gas produced by foods high in complex carbohydrates. Each bases its effectiveness on an enzyme derived from the aspergillus plant, which promoters say helps break down complex sugars early in the digestive process.

Do they help? Find out for yourself. For free samples, call (800) GET-BEANO or the Be Sure Gas Busters hotline at (800) 688-3933.