Healthnotes Newswire (April 10, 2008)—People who have had gallstones have probably heard the standard recommendations: lose weight, avoid saturated fats, and get lots of fiber. A new study suggests that getting plenty of magnesium might also offer some protection.

The study, published in the American Journal of Gastroenterology, followed more than 42,000 men between ages 40 and 75 for 16 years. The men filled out health questionnaires every two years and diet questionnaires every four years. Those with the highest magnesium intake—more than 409 mg per day from food and supplements—were 28% less likely to develop gallstones than those whose intake was the lowest, at less than 288 mg per day.

Gallstones form when bile becomes saturated with cholesterol and forms crystals made of cholesterol and bile salts. Crystals form on top of other crystals and eventually the formation becomes a stone. If a large gallstone makes its ways to the duct that connects the gall bladder to the small intestine (common bile duct), it can cause an obstruction, a painful situation that requires emergency medical attention.

Most of the time, gallstones sit benignly in the gall bladder causing only minor symptoms such as indigestion or no symptoms at all. A large, fatty meal can sometimes elicit symptoms (intense pain, nausea, and sometimes vomiting) in people whose gallstones are otherwise quiet. For many people who suffer frequently from these gall bladder attacks, the gall bladder is surgically removed.

Good nutrition = gallstone prevention

The best prevention methods are to get plenty of exercise, eat a high-fiber diet, and avoid high-fat foods, especially deep fried foods and animal fats from cheese, butter, and fatty meats. Maintaining a normal weight and moderating intake of sugar and calories can also help.

Magnesium-rich foods, like nuts, whole grains, beans, green leafy vegetables, fish, and meat, are unprocessed, mostly high in fiber and low in saturated fat, and rich in other nutrients. A diet full of highly processed foods and fast foods is usually magnesium-poor.

“This study identified a potential link between magnesium-rich foods and reduced risk of gallstones,” commented Mary Saucier Choate, a registered dietitian and food and nutrition educator at two Co-op Food Stores in New Hampshire, and author of the Better Eating for Life book and class series. “A diet low in magnesium is surely low in other nutrients, and it could be that preventing gallstones requires a synergistic action between magnesium and the other nutrients in the same foods. More and more the research is showing us that it’s the whole food and the whole diet, not isolated nutrients, that keeps us healthy.”

Magnesium supplements have been found to be helpful in reducing high blood pressure, correcting abnormal heart rhythms, maintaining good bone density, preventing painful periods, interrupting migraine headaches, and managing blood sugar levels. Although the results from this study do not show definitively whether supplementing with magnesium can contribute to gallstone prevention, many experts believe that adding extra magnesium to a healthy diet—whether alone, in a multivitamin, or in combination with calcium—is a good, safe practice.

(Am J Gastroenterol 2008;103:375–82)