GAS

The purpose of the gastrointestinal (GI) tract is to extract fluid and essential nutrients from the food we eat and to eliminate wastes. All the way along the tract, food is propelled by involuntary rhythmic muscular contractions called peristalsis. From the mouth, ingested food proceeds down a straight tube called the esophagus into the stomach. It is here that the process of digestion begins, with stomach acid being secreted to break down food. Enzymes that also facilitate the breakdown of chemicals in food, permitting absorption into the bloodstream, are secreted here and in subsequent sections of the GI tract. From the stomach, food passes into the small intestine, a relatively thin, long (12 feet) tube with three distinct portions: duodenum, jejunum, and ileum. Enzymes from the pancreas and the gallbladder enter at the duodenum and have specific roles in the digestion of food. Generally, several hours later, the remaining food passes from the ileum into the large intestine or colon. The appendix is a pouch of uncertain function close to the junction between the large and small intestines. Water and some remaining nutrients are extracted in the large intestine, before the remains are excreted through the rectum as stool. 

Gas

One of the miracles of modern Madison Avenue marketing is that the public is still spending money for simethicone, alone or in combination with other drugs, for gas or infant colic.

Despite the millions spent on advertising to convince us otherwise, the feeling of bloating and pain after eating is not caused by gas. There is no relation between these symptoms and the amount of gas in the intestinal tract. The use of antigas products to relieve this discomfort is inappropriate, as there is no medical need to expel gas from the body.

There are two major sources of gas in the gastrointestinal tract. The first is swallowed air that is either released in belching or continues through the intestines and must be passed as flatus. Gas is also produced in the large intestine by normal bacteria and must eventually leave the body as flatus through the rectum. Both of these processes are perfectly normal.

In 1975, The Medical Letter on Drugs and Therapeutics, one of the world’s most respected sources of objective drug information, wrote: "There is no convincing evidence that simethicone, alone or in combination, is effective for the treatment of flatulence [gas] associated with functional disorders of the gastrointestinal tract."[1] Two decades later, a randomized trial of 83 infants between two and eight weeks of age with colic found no significant difference between simethicone and placebo (a look-alike dummy drug).[2] The Medical Letter reviewed simethicone again in 1996 and said: "There is no convincing evidence that simethicone, alone or in combination, is effective for treatment of eructation [belching], flatulence or any other signs or symptoms of excess gastrointestinal gas."[3] The best approach to gas is to avoid those foods you have identified as problems for you.