Effect of coffee feeding on the duodenal transport and bile excretion of calcium in the rat
1988
Yeh, J.K. | Aloia, J.F.
Caffeine administration increases endogenous fecal calcium and urinary calucium excreation resulting in a deterioration of calcium balance. The aim of the current study was to investigate the effect of coffee feeding on the intestinal transport of calcium and the mechanism of enhancement of endogenous calcium secretion. A group of rats were fed a diet containing 4% instant coffee and their calcium metabolism was campared to a control group fed the same diet with cellulose replacing the instant coffee. The results of the calcium balance study showed that 3 weeks of coffee consumption caused an increase in endogenous fecal calcium and urinary calcium excreation without a change in the absorption coefficient of calcium. We used an in vivo ligated loop technique to fractionate the calcium of the bile from that of the mucosal efflux and pancreatic secretions. The results indicated that the enhancement of endogenous calcium secretion into the duodenal lumen was from an increase in bile secretion and in mucosal efflux. When the bile flow rate was measured by direct cannulation of the bile duct, we were able to demonstrate that chronic coffee feeding resulted in a 45% increase in the bile flow rate without a change in the calcium concentration in the bile fluid.
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