Weight reduction and gallstone formation

Nutrition Research Newsletter, Oct, 1989 by R.A. Liddle, R.B. Goldstein, J. Saxton

WEIGHT REDUCTION AND GALLSTONE FORMATION

As noted in the previous article, obesity is associated with the development of gallstones. There is concern, however, that trying to reduce the risk through weight reduction may itself predispose individuals to experience symptomatic gallstones. Fifty-one obese adults (13 men and 38 women, aged 27 to 68 years) enrolling in a weight reduction program in San Francisco were selected as study subjects; 26 obese, non-dieters (12 men and 14 women, aged 32 to 56 years) served as controls. Subjects had no gallbladder sludge or stones as determined by abdominal ultrasound examinations. Dieting subjects were placed on a 2,100 kJ/day diet consisting of 74 g protein, 49 g carbohydrate, and 1 g fat. Initial body weights averaged 105.9 [ or -] 3.8 kg (162% of ideal weight) and dropped to 89.4 [ or -] 3.2 kg (137.3% of ideal weight) after eight weeks. After four weeks on the diet, four subjects had developed gallstones and one subject had sludge as well. After eight weeks, 13 people had gallstones, two of whom had sludge and one of whom required surgery. No signs of gallstone formation were observed among the non-dieting subjects. There were no significant differences in age, sex, initial weight, or amount of weight loss at four or eight weeks between those who developed gallstones and those who maintained normal gallbladders. Gallstone-developers did, however, have significantly higher serum transaminase levels. After reinstituting a normal diet, two subjects with gallstones underwent cholecystectomy. Of the remaining 10 gallstone formers, four subjects no longer showed the presence of stones after six months, while four new gallstone formers were identified. The results of this study suggest that prolonged caloric restriction may predispose to the development of gallstones, and that higher aspartate aminotransferase levels may be a predictor of risk for gallstone formation during weight reduction.