RESUMEN
Undue use of vitamin C has resulted concerns over some the harmful effects of it. To examine the effect of vitamin C on serum level of copper, zinc, iron parameters, and the ceruloplasmin enzyme activity. This was a double-blind clinical trial carried out in 1999 in Iran Research Institute for Nutrition and Food Sciences in healthy men. Volunteers were divided into 3 groups. Ascorbic acid was given to first two groups at the concentrations of 500mg/day and 1000 mg/day, respectively. No ascorbic acid was delivered to the third group [control group]. Fastting blood samples were collected in the beginning and at the end of the study period [6th week]. Copper and zinc concentrations were determined by atomic absorption; ceruloplasmin enzyme activity and vitamin C levels by colorimetric method; iron, TIBC and hemoglobin by employing a kit from zist-chimi company; and the percent of transferring saturation was calculated using the formula: serum iron/TIBCx100. Dietary consumption pattern in the beginning and at the end of the study period were recorded using 24hr dietary recall questionnaire for one day. Mean Blood ascorbic acid concentration increased by 67% [p=0.001], 76% [p=0.001], and 23% [p=0.04] in groups marked as 500 mg/day, 1000 mg/day ascorbic acid and control groups, respectively. This was statistically significant at the end of study. Mean ceruloplasmin enzyme activity decreased [p=0.004] in group 1000 mg/day ascorbic acid at the 6th week which was statistically significant. In spite of changes in serum copper and iron levels, these changes were not significant, statistically. Vitamin C had no effect on zinc concentration. No significant change was present in food consumption pattern during the study period. Based on present data, vitamin supplementation at daily doses of 500 and 1000 mg cannot be recommended and further are needed in this regard