Consumption of insoluble fibre may decrease the risk of gallbladder surgery in women, according to a study examining the relationship between dietary fibre and gallstone disease. As part of the Nurse’s Health Study, (see note) approximately 70,000 women completed biennial questionnaires on their fibre intake, as well as whether or not they had undergone gallbladder surgery. Data was collected over a 16-year period and the participants had no prior diagnosis of gallstone disease or cancer.
Findings showed that women who consumed the most fibre overall were 6% less likely to undergo gallbladder removal. After adjusting for suspected and known risk-factors for gallstones (including age, body-mass index, physical activity, smoking habits, and saturated fat consumption) the correlation between fibre intake and lowered risk of gallbladder disease became even more apparent. With the above variables accounted for, those with the highest amounts of dietary fibre were 13% less likely to undergo surgery.
Most significantly, the type of fibre consumed was found to be key. When researchers controlled for soluble and insoluble fibre consumption simultaneously, women with the highest insoluble fibre intake had a 17% lowered risk of gallbladder surgery.
While the mechanisms that reduce the risk are not fully understood, researchers speculate that the effects of dietary fibre on gallbladder disease may be related to its effect on the bile acid metabolism. In Western countries, about 80% of gallstones are cholesterol stones, the formation of which has been linked to biliary hypersecretion. Dietary insoluble fibre can help to speed intestinal transit time, reduce the production of bile acids and assist in decreasing bile cholesterol levels. Researchers concluded by noting the “important beneficial effect of dietary fibre, particularly insoluble fibre” in reducing the risk of gallbladder surgery.
Insoluble fibres include lignin, cellulose, and hemicellulose and are found in vegetables, wheat, and cereals.
Note: The Nurses’ Health Study is among the largest prospective research studies examining the risk factors for the development of major chronic disease among women.