The Gallbladder : The Role of Diet, Drug Treatment

by Food and Drug Administration (FDA)

(Page 2 of 3)

Studies indicate that gallstones are more prevalent in some populations than others, but it is difficult to tell whether this is due to heredity or environmental factors. For example, gallstones are common in the United States (with 20 million sufferers) and Great Britain (with 100,000 affected) and have the highest incidence in Sweden, where 44 percent of the population is affected. Yet gallstones are very rare in Africa and Asia.

But does prevalent gallbladder disease reflect a particular diet, or genetic similarity among the people? It's hard to say.

The fact that the rate of gallbladder disease is high in cultures with high-fat, low-fiber diets and low in cultures with high-fiber, low-fat diets suggests a nutritional influence. In addition, people who move from the high-fiber, low-fat areas to high-fat, low-fiber areas soon develop more gallbladder disease. For example, East Asians moving to the United States and adopting our fattier diet show a sixfold increase in gallbladder problems within a single generation.

On the other hand, certain population groups, most notably Native Americans, have a high incidence of gallbladder disease, leading scientists to suspect a hereditary factor. About 80 percent of the Pima Indians of southern Arizona develop gallstones by age 35. Numbers are also high among the Navajos of the southwestern states, the Chippewas of northern Minnesota, the Micmacs of Nova Scotia, Alaskan tribes, and especially the Araucanian Indians of Chile. Another genetic link is the association of pigment gallstones with sickle cell disease, an inherited anemia most common in blacks.

The Role of Diet

Since the gallbladder is part of the digestive system, it seems logical that its health would depend, at least in part, on what one eats. Establishing a dietary cause of gallbladder disease is difficult.

Still, some clinical studies track interesting trends. A group of Boston researchers led by K. Malcolm MacLure, Sc.D., of the Harvard School of Public Health, and Walter C. Willett, M.D., of Harvard Medical School, followed 88,837 women between the ages of 34 and 59 who had filled out a detailed dietary questionnaire in 1980. By 1984, 433 had had their gallbladders removed, and 179 had stones not yet treated. What, if anything, did these women have or do that the others didn't? Weight.

"Overall, we observed a roughly linear relation between relative weight and the risk of gallstones," write the researchers in the Aug. 31, 1989, issue of the New England Journal of Medicine. They warn that even moderate overweight can raise the risk, estimating that the very obese face a sixfold higher risk, and the slightly overweight a 1.7-fold increase in risk.

A team led by Harris Pastides, Ph.D., of the University of Massachusetts School of Public Health in Amherst, compared the diets of 84 female and 16 male gallbladder patients admitted consecutively to a hospital in Athens, Greece, to accident victims without gallbladder problems. They conclude in the July 1990 Archives of Internal Medicine, "Our findings suggest that there is a rather strong association between frequent consumption of starchy food items such as breads, pasta, rice, and potatoes with risk of gallbladder disease in women. Furthermore, a modest protective effect was observed among women reporting relatively high consumption of vegetables of all kinds." They recommend that overweight women with starchy diets try to include more vegetables.

But the diet-gallbladder link, if indeed there is one, is far from clear. Consider a class action suit being filed against a popular dietary plan. "Last spring, according to newspaper reports, 19 people filed suit against NutriSystem for developing gallbladder disease after the diet," says Carol Heppe, a consumer safety officer at the Food and Drug Administration. But would they have become ill anyway? There is no ready answer.

For women, common risk factors for developing the disease include age, weight, and number of children. Among obese women between 20 and 30 years of age, the risk is six times greater than that for women of normal weight. By age 60, almost one-third of obese women can expect to develop gallbladder disease.

Drug Treatment

Drug treatment to dissolve gallstones began about 20 years ago, when researchers found that a deficiency of bile salts enabled cholesterol to crystallize out of solution and form stones. Today, drugs are typically given for small stones or if a person cannot tolerate surgery.

The two approved cholesterol gallstone dissolution drugs are the natural bile constituents chenodeoxycholic acid (Chenix) and its chemical non-identical twin ursodeoxycholic acid (Actigall).

"These drugs can change the cholesterol saturation in the gallbladder and permit cholesterol in the stone to go into solution, so that it dissolves," says Stephen Fredd, M.D., director of FDA's division of gastrointestinal and coagulation drug products at FDA. "Ursodeoxycholic acid is less likely to be toxic to the liver, but is more expensive."

But the drugs have major drawbacks. "In 50 percent of patients, stones recur within 5 years of drug treatment," explains Fredd. "A common side effect of these drugs is diarrhea. The drugs work slowly and must be taken daily for a long time and, even then, are not always effective. About 12 percent of patients improve after six months, and up to 50 percent show improvement by a year. The cost of drug treatment is about $1,200 a year.

A new investigational drug is methyl-tert-butyl-ether. It works fast on cholesterol stones, dissolving them in 24 to 48 hours, but administering the drug is an invasive procedure.

"It is not taken orally," explains Fredd. "It is put in the gallbladder by a catheter through the liver to the gallbladder. This is not minor stuff, but in expert hands, it can be done safely. But it has dangerous propensities. It is an ether, and can put you to sleep. It can irritate the intestines."

Another new drug is mono-octanoin (Moctanin), which is approved only to treat stones lodged in the common bile duct. This sometimes happens after the gallbladder is removed and small stones migrate into the duct.

About the Author

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