A pilot study of antioxidant intake in patients with cholesterol gallstones.

Whereas macronutrient intake has been extensively investigated in an attempt to unravel the pathogenesis of human cholesterol gallstones, theoretical considerations and animal models suggest that deficits in micronutrient antioxidants may be more relevant. We report a pilot study of this aspect. The plan was to obtain 7-d weighed food inventories over a 6-mo period from equal numbers of patients who had not consciously changed their diets, patients who were on low-fat diets and age- and gender-matched controls. Food tables would be used to derive daily intakes of 16 known antioxidants, essential amino acids, and essential fatty acids. Under-reporting of food intake, a recognized drawback of this dietary method, would be sought retrospectively by reference to a key publication giving minimum cut-off limits for ratios of energy intakes to basal metabolic rates. There were 18 pairs for study. Analysis of data for the 9 pairs involving patients on their normal diets showed no differences in the intakes of energy macronutrients, and cholesterol, but the patients ingested lower amounts of 10 among 16 antioxidants (P < 0.05 for methionine, alpha-tocopherol, manganese, and vitamin D; 0.05 < P < 0.10 for cysteine, beta-carotene, vitamin C, selenium, zinc, and phosphorus). Both subsets of patients ingested lower amounts of linoleic acid (diet unchanged P = 0.009, changed P = 0.026) and several essential amino acids than did matched controls. Institution of a low-fat diet caused the expected fall in intakes of energy and saturated fatty acids such that the deficit in alpha-tocopherol was amplified, but substitution of fruit and vegetables by the patients resulted in a fortuitous increase in vitamin C, beta-carotene, and manganese intake. Retrospective analysis confirmed under-reporting of food intake by all four subsets of subjects but there was no significant difference in the mean ratio of energy intake to estimated basal metabolic rate in the subset of patients who had not consciously altered their diets and the subset of matched controls. Furthermore, the lower daily intake of alpha-tocopherol and linoleic acid by these patients persisted when results were expressed relative to total fat consumption. The results support the hypothesis that insufficiency of dietary antioxidants, particularly alpha-tocopherol, may be germane to human gallstone disease; they also suggest that low intakes of linoleic acid and essential amino acids may be relevant. Because of the small sample sizes, however, these deductions should be regarded as tentative, pending confirmation by biochemical analysis of blood and especially of hepatic bile.