Calcium absorption after intestinal resection. The importance of a preserved colon.

Calcium absorption was studied in 62 patients with Crohn's disease during a 1-week admission on a standardized diet supplying 70 g fat, 800 mg calcium, and 200 mg oxalate. All patients had been subjected to a distal small-bowel resection of at least 50 cm. Twenty-two had an ileostomy, and 40 had at least half of the colon in function. In all patients the disease was inactive. Calcium absorption was determined by the fractional accumulation in the skeleton of the antebrachium of an intravenous and oral dose of 47Ca. Calcium absorption was significantly lower in patients with ileostomy (median, 10%; range, 5-18%) than in patients with part of or the whole colon in function (median, 14%; range, 6-22%). The present study shows that in patients with extensive small-bowel resection preservation of at least half of the colon improves calcium absorption.