Consuming a half-serving, or one tablespoon, of peanut butter (about 95 calories) five or more times a week is associated with a 15% reduced risk. Small, daily servings of peanuts and peanut butter have previously been shown to reduce the risk of heart disease and type 2 diabetes as well.
Gallstones are associated with high triglyceride levels and low "good" HDL cholesterol levels, which are also risk factors for heart disease.
The research states that in addition to the well-documented benefits of healthy mono- and polyunsaturated fats in peanuts and nuts, other bioactive components may play a role. Peanuts and nuts are rich sources of dietary fiber, which may contribute to reducing the risk of gallstones by improving insulin sensitivity and decreasing recirculation of bile acids. A one-ounce serving of peanuts contains about two and a half grams of fiber.
Peanuts, nuts and peanut butter are rich sources of magnesium, which also could explain reduction in risk of cholecystectomy. The paper suggests that dietary magnesium plays a role in improving insulin sensitivity, thereby reducing the occurrence of gallstones. They also contain phytosterols, which may help lower blood cholesterol, and help reduce the risk of gallstones.