Zinc absorption in celiac disease and dermatitis herpetiformis: a test of small intestinal function

The increments in plasma zinc concentrations after an oral dose of elemental zinc (50 mg) as the sulphate were used to assess the intestinal absorption of the metal in 11 patients with dermatitis herpetiformis (DH) before starting a gluten-free diet, 12 patients with newly diagnosed celiac disease (CD), 10 patients known to have CD, and 15 healthy volunteers. The areas under the plasma zinc increment curve plotted against time were determined for 3 (AUC3) and 6 (AUC6) h. The AUC3 in healthy volunteers was 401 +/- 48 mumol 1(-1) 3 h (mean +/- SD); it was reduced in newly diagnosed CD 187 +/- 76 mumol 1(-1) 3 h (p less than 0.001), and in dermatitis herpetiformis 206 +/- 87 mumol 1(-1) 3 h (p less than 0.01); but it was normal in the known CD 396 +/- 204 mumol 1(-1) 3 h, the wide variation reflecting the variable compliance with a previously instituted gluten-free diet. The AUC6 was similarly affected, healthy volunteers 700 +/- 111 mumol 1(-1) 6 h, new CD 380 +/- 169 mumol 1(-1) 6 h (p less than 0.01); dermatitis herpetiformis 471 +/- 107 mumol 1(-1) 6 h (p less than 0.01); known CD 725 +/- 380 mumol 1(-1) 6 h. The AUC3 was more consistently abnormal than conventional tests of small intestinal function. In a prospective study the AUC3 and AUC6 improved and reflected compliance with a gluten-free diet.