Q: I had an abdominal ultrasound that showed I have gallstones. My digestion is fine. Do I need to do anything about them?
A: Most people who have gallstones don’t know it. Their gallstones stay silent and may only be discovered incidentally, through an ultrasound or CT scan performed for other reasons.
Gallstones begin with bile, a substance that helps with the digestion of fats and the absorption of certain vitamins. Bile is made in the liver and carried to the gallbladder, a small, pear-shaped organ that concentrates and stores it.
Gallstones are solid lumps that develop when the stored bile crystallizes. Most are less than an inch in diameter, but they can be as small as a grain of sand or as large as a golf ball. Most gallstones are composed mainly of cholesterol.
Cholesterol stones form when liquid bile in the gallbladder contains more cholesterol than the bile salts can dissolve. Cholesterol stones may also develop if the gallbladder doesn’t contract and empty as it should.
Before age 40, women are diagnosed with gallstones almost three times more often than men are, but by age 60, their risk is just slightly greater. Obesity is another risk factor because bodies with more fat produce more estrogen. Paradoxically, rapid weight loss also increases the risk. Gallstones are also more likely to occur in people with diabetes and in postmenopausal women who take oral estrogen.
Symptoms arise mainly when stones pass through a bile duct or obstruct it, causing biliary colic — better known as a gallbladder attack. These attacks occur when the gallbladder contracts (usually in response to a fatty meal) and presses the stones so as to block the gallbladder duct. The main symptom is pain, usually in the right upper or middle abdomen (just below the rib cage), which builds to greatest intensity within an hour and can persist up to several hours. The pain usually subsides as the gallbladder relaxes.
Typically, gallstones are treated only if they cause symptoms. For recurrent gallbladder attacks or gallstones that have caused complications, the most effective treatment is surgical removal of the gallbladder. The preferred procedure is laparoscopy, with a much faster recovery than traditional cholecystectomy.
There’s no proven way to prevent you from getting more gallstones, but research suggests some possibilities. Eat three well-balanced meals daily, replace saturated fats with mono- and polyunsaturated fats, maintain a normal weight, and get regular exercise (at least 30 minutes a day most days of the week). The Nurses’ Health Study also found that women with more fiber in their diets and those who ate several 1-ounce servings of nuts per week were less likely to need gallbladder surgery.
(Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, please visit www.health.harvard.edu.)