Comparison of plasma, mononuclear and polymorphonuclear leucocyte vitamin C levels in young and elderly women during depletion and supplementation
Blanchard, J.; Conrad, K.A.; Watson, R.R.; Garry, P.J.; Crawley, J.D.
European Journal of Clinical Nutrition 43(2): 97-106
1989
ISSN/ISBN: 0954-3007 PMID: 2707219 Document Number: 334079
Concentrations of vitamin C in plasma, mononuclear (MN) and polymorphonuclear (PMN) leukocytes were measured in healthy, free-living, young and elderly women on 3 occasions during 8 to 10 weeks: at entry into the study; after 5 weeks of dietary depletion of vitamin C; and after 3 weeks of daily supplementation with 500 mg vitamin C. The combined mean vitamin C values (expressed as mu g/108 cells) in MN cells were higher than those in PMN cells at all 3 times, although the difference was statistically significant only in the depleted state. There were no age-related differences in the values of vitamin C in plasma, MN or PMN cells at any of the 3 times. There were significant overall differences in vitamin C values between the entry and depleted and the depleted and supplemented states for plasma and PMN cells but not for MN cells, possibly indicating that plasma and PMN cells are more sensitive indicators of vitamin C status than MN cells. The mean values of vitamin C in plasma clearly do 'track' those in MN and PMN cells. However, attempted correlations between plasma and MN, plasma and PMN, and MN and PMN vitamin C values at each time were not significant. In addition, the changes in vitamin C values from entry to depleted and from depleted to supplemented times were not significant when comparing plasma with MN and plasma with PMN, whereas the MN to PMN comparison indicated a significant change in vitamin C values between the depleted and supplemented states. Thus, although the average plasma values reflect changes in the mean MN and PMN vitamin C values, plasma values were not reliable in predicting the MN or PMN values within an individual.