All of us at one time or another have complained about indigestion. Indigestion is a term that is used regularly, yet the symptoms it describes differ from person to person and it is up to the healthcare professional to listen to those symptoms to determine what the real problem is. Most people use the word to describe some type of upper gastrointestinal discomfort that is related to eating. Others experience stomach pain and gas. Others report intolerance to certain foods and a need to belch. All of these complaints are involved in indigestion and when they become disturbing, it is time to seek the advice of a healthcare professional.

Some people complain of chronic, repetitive belching. In most instances, each belch is preceded by a large gulp of air which passes only part of the way down the esophagus before it is expelled. Air swallowing is what generally causes excessive belching, not the production of gas in the stomach or intestine. Everyone swallows a bit of air, but some people gulp air excessively causing repeated belching. Some causes include chronic anxiety, rapid eating, drinking carbonated beverages (or any beverage through a straw), gum chewing, sucking on hard candy, smoking cigarettes, poorly fitting dentures, postnasal drip, or esophageal speech.

About 20-60 percent of intestinal gas is swallowed air. We know this because we can measure nitrogen and oxygen in the intestines and since the body does not make either of those gases, it stands to reason that the air was swallowed.(1) When swallowed air is not expelled, it passes into the stomach and intestine, giving a feeling of fullness and pressure. Upon x-ray, a large amount of air may be seen in the gastric fundus. This symptom complex is known as the gastric bubble syndrome, and may occur if the individual lies down after a meal, allowing air to become trapped by overlying fluid. This is the same condition thought to cause the "gas-bloat" syndrome observed after surgical repair of a hiatal hernia.

Many people think that the feelings of abdominal pain and bloating they experience is due to production of excessive gas. Studies have shown that these people have a normal amount of gas but may be hypersensitive to the associated pain. The average individual normally has 150 to 300ml of gas or less in the stomach and colon at any one time.(2) The amount expelled in the average person is 476 to 1,491ml daily.(3, 4) Clues to the causes of excessive flatulence can come from analysis of the gases. Gas originates from swallowed atmospheric air, bicarbonate neutralization of stomach acids, diffusion of gases into the intestine from the blood, and bacterial fermentation.(5) The main gases produced are hydrogen and carbon dioxide. There are minute quantities of other gases and, of course, sulfur-containing compounds that give gas its characteristic odor. About one-third of the population produces methane.

Some foods, such as legumes and certain grains, increase the production of gas. These foods contain significant quantities of nonabsorbable complex carbohydrates that pass into the colon, providing an excellent place for gas-producing bacteria to grow. The most commonly studied of these foods is beans, which contain oligosaccharides that cannot be broken down in the small bowel, but pass into the colon and are metabolized by colonic bacteria. Fructose, a natural or added sweetener in fruit, fruit juices and soft drinks, and also present in oligosaccharides in, among others, broccoli, onions, asparagus, and wheat, may also be incompletely absorbed in the small intestine, and add to abdominal distention, bloating, and flatulence.

Intestinal malabsorption of sorbitol, a product used in many "sugar free" gums and candies and also used as an inert ingredient in some medications, may also cause abdominal distent