Indigestion (Dyspepsia, Upset Stomach)

  • Medical Author:
    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Diet and indigestion

Dietary factors have not been well-studied in the treatment of indigestion. Nevertheless, people often associate their symptoms with specific foods (such as salads and fats). Although specific foods might worsen the symptoms of indigestion, they usually are not the cause of indigestion. (Intolerance to specific foods, for example, lactose intolerance [milk] and allergies to wheat, eggs, soy, and milk protein are not considered functional diseases like indigestion). The common placebo response in functional disorders such as indigestion also may explain the improvement of symptoms in some people with the elimination of specific foods.

Dietary fiber often is recommended for patients with IBS, but fiber has not been studied in the treatment of indigestion. Nevertheless, it probably is reasonable to treat patients with indigestion with fiber if they also have constipation.

Intolerance to lactose (the sugar in milk) often is blamed for indigestion. Since indigestion and lactose intolerance both are common, the two conditions may coexist. In this situation, restricting lactose will improve the symptoms of lactose intolerance, but will not affect the symptoms of indigestion. Lactose intolerance is easily determined by a milk challenge testing the effects of lactose (hydrogen breath testing) or trying a strict lactose elimination diet. If lactose is determined to be responsible for some or all of the symptoms, elimination of lactose-containing foods is appropriate. Unfortunately, many patients stop drinking milk or eating milk-containing foods without good evidence that it improves their symptoms. This often is detrimental to their intake of calcium which may contribute to osteoporosis.

One of the food substances most commonly associated with the symptoms of indigestion is fat. The scientific evidence that fat causes indigestion is weak. Most of the support is anecdotal (not based on carefully done, scientific studies). Nevertheless, fat is one of the most potent influences on gastrointestinal function. (It tends to slow down the gastrointestinal muscles while it causes the muscles of the gallbladder to contract.) Therefore, it is possible that fat may worsen indigestion even though it doesn't cause it. Moreover, reducing the ingestion of fat might relieve symptoms. A strict low fat diet can be accomplished fairly easily and is worth trying. Additionally, there are other health-related reasons for reducing dietary fat.

Other dietary factors, fructose, and other sugar-related foods (fermentable, oligo- di- and mono-saccharides and polyols or FODMAPs), have been suggested as a cause of indigestion since many people do not fully digest and absorb them before they reach the distal intestine. Fructose intolerance and perhaps also FODMAP intolerance can be diagnosed with a hydrogen breath test using fructose and treated by elimination of fructose and/or FODMAP containing foods from the diet. Unfortunately, fructose and FODMAPs are widespread among fruits and vegetables, and fructose is found in high concentrations in many food products sweetened with corn syrup. Thus, an elimination diet can be difficult to maintain.

Pro-motility medication for indigestion

One of the leading theories for the cause of indigestion is abnormalities in the way gastrointestinal muscles function. The function of muscles may be abnormally increased, abnormally decreased, or it may by uncoordinated. There are medications, called smooth muscle relaxants that can reduce the activity of the muscles and other drugs that can increase the activity of the muscles, called promotility drugs.

Many of the symptoms of indigestion can be explained on the basis of reduced activity of the gastrointestinal muscles that results in slowed transport (transit) of food through the stomach and intestine. (It is clear, as discussed previously, that there are other causes of these symptoms in addition to slowed transit.) Such symptoms include nausea, vomiting, and abdominal bloating. When transit is severely affected, abdominal distention (swelling) also may occur and can result in abdominal pain. (Early satiety is unlikely to be a function of slowed transit because it occurs too early for slowed transit to have consequences.) Theoretically, drugs that speed up the transit of food should, in at least some patients, relieve symptoms of indigestion that are due to slow transit.

The number of promotility drugs that are available for use clinically is limited. Studies of their effectiveness in indigestion are even more limited. The most studied drug is cisapride (Propulsid), a promotility drug that was withdrawn from the market because of serious cardiac side effects. (Newer drugs that have similar effects but lack the toxicity are being developed.) The few studies with cisapride for indigestion were inconsistent in their results. Some studies demonstrated benefits whereas others showed no benefit. Cisapride was effective in patients with severe emptying problems of the stomach (gastroparesis) or severely slowed transit of food through the small intestine (chronic intestinal pseudo-obstruction). These two diseases may or may not be related to indigestion.

Another promotility drug that is available is erythromycin, an antibiotic that stimulates gastrointestinal smooth muscle as one of its side effects. Erythromycin is used to stimulate smooth muscles of the gastrointestinal tract at doses that are lower than those used for treating infections. There are no studies of erythromycin in indigestion, but erythromycin is effective in gastroparesis and probably also in chronic intestinal pseudo-obstruction.

Metoclopramide (Reglan) is another promotility drug that is available. It has not been studied, however, in indigestion. Moreover, it is associated with some troubling side effects. Therefore, it may not be a good drug to undergo further testing in indigestion.

Domperidone (Motilium) is a promotility drug that is available in the U.S., but requires a special permit from the US Food and Drug administration. As a result, it is not very commonly prescribed. It is an effective drug with minimal side effects.

Medically Reviewed by a Doctor on 10/28/2016
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