INFLUENCE OF A HYPOLIPIDIC DIET ON GALLBLADDER EMPTYING

Little is known of the effects of meal composition on gallbladder emptying and cholecystokinin (CCK) release in man. Gallbladder volumes (measured by means of real time ultrasonography) and plasma CCK levels (determined by radioimmunoassay) were studied in 5 normal subjects, before and after a normal solid-liquid meal, and before and after a low-fat, low-protein, solid-liquid meal after 3 days regimen with low-fat, low-protein meal. Low-fat, low-protein regimen significantly increased gallbladder fasting volume and significantly decreased fasting plasma CCK levels. This suggests that CCK secretion regulates fasting gallbladder volume and that basal CCK secretion depends on diet composition. After a normal meal, gallbladder emptying was biphasic with a 44 % volume decrease within the first 15 min followed by slower emptying during the next 60 min with a final volume reaching less than 15 % of the fasting volume. After a hypolipidic, hypoproteic meal, the initial 15 min emptying (42 %) was the same as after control meals but no further decrease of gallbladder volume was observed. This study shows that the initial phase of post prandial gallbladder contraction is not dependent on meal composition which affects late gallbladder emptying only. We conclude that a low-fat, low-protein diet, increasing gallbladder fasting volume and decreasing gallbladder emptying, may favor gallbladder stasis and therefore increase the risk of gallstone formation.