BOSTON, MASSACHUSETTS. Gallstones are a major problem in the developed world and their presence often necessitates surgery (cholecystectomy) to remove them. Researchers at the Harvard Medical School now report that the frequent consumption of nuts and nut butters substantially reduces the risk of cholecystectomy in women. Their study involved 81,000 female nurses who were 30 to 55 years old at the beginning of the study (1980) and had no history of gallstone problems. During 20 years of follow-up, 7831 women underwent a cholecystectomy (0.6% per year). After adjusting for age and other known or suspected risk factors for gallstones, the researchers concluded that women who consumed at least 5 ounces (140 grams) of nuts per week had a 25% lower risk of developing gallstones requiring removal via cholecystectomy than did women who rarely ate nuts or peanut butter.
Peanut consumption was associated with a 19% decrease in risk, peanut butter consumption with a 15%
decrease, and the consumption of other nuts with a 35% decrease. The researchers believe that nuts
protect against the formation of gallstones (usually cholesterol-based) because they are a good source of
dietary fiber, unsaturated fatty acids, magnesium and phytosterols. All these components either improve
insulin sensitivity or reduce blood cholesterol levels.