Vitamin A deficiency in Crohn's disease.

Fifty two patients with Crohn's disease (31 outpatients and 21 inpatients) were investigated for evidence of vitamin A deficiency. Eleven (21%) had low plasma retinol concentrations (less than 1.2 mumol/l (34.3 micrograms %)). Five of these were outpatients and plasma retinol was only slightly reduced (greater than 1.0 mumol/l (28.6%)). All outpatients weighed 80% or more of ideal, and were considered at low risk of developing vitamin A deficiency. In contrast, of the six inpatients with low plasma retinol concentration, five had a level of less than 1.0 mumol/l (28.6 micrograms %) and weighed less than 80% ideal. Three of these had impaired dark adaptation and a plasma retinol concentration of less than 0.8 mumol/l (less than 22.9 micrograms %). As a group, the inpatients were more protein depleted than the outpatients, with respect to serum albumin (p less than 0.01), transferrin (p less than 0.001), and prealbumin (p less than 0.001) but retinol binding protein levels were not significantly lower. It is suggested that patients with extensive small bowel Crohn's disease, who weigh less than 80% of ideal weight, merit measurement of plasma retinol concentration. Those with plasma retinol less than 0.8 mumol/l (less than 22.9 micrograms %) run a high risk of night blindness. Vitamin supplements should be given and protein depletion corrected.