Plasma and urinary zinc in patients with malabsorption syndromes or hepatic cirrhosis

Plasma and urinary zinc have been measured in 19 patients with malabsorption and 21 patients with hepatic cirrhosis. The results have been compared with those of 20 control subjects and 23 patients with a variety of other diseases. The diurnal variation in plasma zinc levels has been confirmed and is of such magnitude that this must be taken into account in comparing results in groups of subjects. Plasma zinc levels, both fasting and after a meal, are significantly lower in patients with cirrhosis (71 and 60 mug/100 ml) and malabsorption (76 and 64 mug/100 ml) than in controls (97 and 81 mug/100 ml). In the patients with cirrhosis or malabsorption similar correlations exist between plasma zinc and plasma albumin, suggesting that the low plasma zinc levels may be, at least in part, dependent on the plasma albumin level. Urinary zinc excretion is increased in cirrhosis, but not in malabsorption, indicating that increased urinary loss is unlikely to explain the low plasma levels.