Nuts and gallstones.

Most people don't think about their gallbladder until it bothers them. The gallbladder is a small sac that squirts bile, a yellowish liquid which helps to digest fat, into the intestines. Under certain conditions, bile can harden and form gallstones that can block tubes leading from the gallbladder to other parts of the body. This blockage produces symptoms like nausea, vomiting, and stomach pain and can even lead to death. More than 800,000 Americans are hospitalized each year because of gallstones; many have to have their gallbladder removed.

Factors like obesity, diabetes, fasting, and rapid weight loss can increase the risk of gallstones. A new study suggests that eating nuts frequently can reduce the risk of gallstone disease in women. Researchers from Harvard Medical School studied more than 80,000 women for 20 years to see who developed gallstones. Women who ate 5 or more ounces of nuts per week had a lower risk of having to have their gallbladder removed because of gallstones compared to women who rarely or never ate nuts. These results were for both peanuts and tree nuts. Factors in nuts that may reduce the risk of gallstones include monounsaturated and polyunsaturated fats, fiber, phytosterols, and magnesium.

Tsai C-J, Leitzmann MF, Hu FB, et al. 2004. Frequent nut consumption and decreased risk of cholecystectomy in women. Am J Clin Nutr 80:76-81.