Copper enzyme activities in cystic fibrosis before and after copper supplementation plus or minus zinc.


Best K.






One laboratory reports low activities for 2 blood copper enzymes in subjects with cystic fibrosis (CF), which suggests that moderate copper deficiency is common in this state. The present study attempted to confirm this proposition in 3 ways: repeat the measures for 1 of the 2 copper enzymes (superoxide dismutase) in a new group of CF patients (males and females, N = 38), add another copper enzyme measure (plasma diamine oxidase) that has high sensitivity to copper status, and test if copper enzyme activities in CF patients rise by copper supplementation. The last test was performed plus or minus zinc supplementation since poor zinc status may contribute to poor copper status. The results for the first 2 aims supported the idea of poor copper status, as low activities were found for CF subjects for 2 copper enzyme activities, erythrocyte superoxide dismutase and plasma diamine oxidase (although normal activities were obtained for another copper enzyme, plasma ceruloplasmin, both as U/mL plasma or U/mg ceruloplasmin immunoreactive protein). For the last aim, copper enzyme activities were not altered by copper supplementation (6 weeks, 3 mg copper/d as copper-glycinate), plus or minus concurrent zinc supplementation (30 mg zinc/d as zinc-glycinate). Therefore, CF may cause a tendency to moderate copper deficiency, which may be due to abnormal copper metabolism not easily corrected by increased copper and/or zinc intake.