The Absorption of Oxalate, Calcium, and Fat after Jejunoileal Bypass

Abstract

The absorption of oxalate, calcium, and fat was studied in 21 patients before and 3 and 12 months after jejunoileal bypass for morbid obesity during a standardized diet supplying fixed amounts of oxalate, calcium, and fat. Eleven patients had an end-to-side anastomosis between 36 cm jejunum and 12 cm ileum, and 10 patients had an end-to-side anastomosis between 12 cm jejunum and 36 cm ileum. Twenty of the 21 patients (95%) developed severe hyperoxaluria postoperatively. No increased incidence of urolithiasis was observed. Three months after operation calcium malabsorption was found in 16 of 20 patients (80%). In most patients calcium absorption increased 12 months postoperatively, but 11 of 20 patients (55%) still had calcium absorption below normal range. Steatorrhoea developed in all patients. The degree of hyperabsorption of oxalate and malabsorption of calcium and fat was independent of the jejunum to ileum ratio. No correlation was found between faecal fat and renal oxalate excretion, faecal fat and ⁴⁷Ca absorption, or ¹⁴C-oxalate absorption and ⁴⁷Ca absorption. Our study shows that after jejunoileal bypass for morbid obesity, enteric hyperoxaluria, calcium malabsorption, and steatorrhoea almost inevitably ensue. Factors other than the intraluminal ratio may be important for the absorption of oxalate, calcium, and fat.

Key-words:

• Calcium malabsorption
• enteric hyperoxaluria
• intestinal shunt operation
• obesity
• steatorrhoea