Bloating, or the sense of swelling in the abdomen, is not necessarily caused by too much gas. Usually bloating is caused by poor motility, or slow movement of the intestinal tract. Bloating is often a symptom of irritable bowel syndrome, a condition of excessive bowel spasm. Eating fatty foods can also slow motility. In rare cases bloating can be a symptom of a more serious disease. For this reason your doctor may order additional tests such as x-rays or an endoscopy. Your doctor may prescribe medications to stimulate the motility of the intestinal tract.
Excessive rectal gas is most often produced by the bacteria in the colon. There are hundreds of different bacteria in the colon; most are harmless, and in fact, helpful to digestion. In the process breaking down nutrients, the bacteria generate a variety of gases. Normally many of these gases are reabsorbed and do not cause excessive flatulence. Some people have disorders that interfere with the digestion of certain foods, such as lactose. Some foods contribute to excess gas, such as beans, cruciferous vegetables and bran. For people that are bothered by excessive gas it may help to try an elimination diet. Experiment with eliminating certain foods for a few days, and then reintroducing them slowly, while observing for increasing symptoms. Some of the foods to eliminate include: legumes, milk products, cruciferous vegetables, root vegetables, some fruits (prunes, raisins, apples, bananas), wheat products, fatty foods and carbonated beverages.