Response of fractional calcium absorption in women to various coadministered oral glucose doses.

Previous studies found an enhancing effect of glucose on fractional calcium absorption in humans but little information is available on the effect of different amounts of carbohydrate on Ca absorption. Thus, we studied the response of fractional Ca absorption to various loads of oral glucose coadministration with Ca in ten female subjects. After an overnight fast, 47Ca was administered orally on four occasions in solutions that contained varying doses of glucose (0 control, 56, 222, and 444 mmol). Seven of the ten subjects showed a positive response to glucose. In this group of responders there was a linear response to glucose between 0 and 222 mmol. No further increase was achieved at the higher dose of glucose. The response to 222 mmol glucose represented a 49% increase in Ca absorption compared with absorption without carbohydrate.