Affiliation:
1. Institute of Experimental Gerontology, Basel, Switzerland
2. Roche Vitamins Europe Ltd, Basel, Switzerland
3. F. Hoffmann-La Roche Ltd., Biostatics, Basel, Switzerland
Abstract
The purpose of this study was to estimate the intake – plasma relationship for vitamin C by means of a meta-analysis. A MEDLINE search revealed 30 publications matching our inclusion criteria. We completed the set with 5 older papers and with one monograph. The proposed statistical model corrects for inconsistencies with regard to methodological differences between the various studies. Therefore, the contribution of a particular study to the estimation is independent of the number of data points. The estimations were performed for the complete data set as well as for different subgroups: “adult” aged 15–65 years, “elderly” aged 60–96 years, “nonsmokers” and “smokers”. The 50th percentile of the plasma concentration for a daily vitamin C intake of 60 mg was 42.4 mumol/L. The corresponding values for the different subgroups were: “adult” 44,1 mumol/L, “elderly” 31.0 mumol/L, “nonsmokers” 42,4 mumol/L, and “smokers” 33.6 mumol/L. Thus, this meta-analysis confirms earlier results that the requirements of vitamin C is higher in “elderly” and “smokers” compared to “adult” and “nonsmokers” and it can be used for the estimation of the vitamin C intake in order to achieve a desired plasma level within a target population. In the general population the assumed optimal plasma concentration of 50 mumol/L, as proposed by a consensus conference, can be achieved by the intake of 100 mg per day, which is the new recommendation of the Austrian, German, and Swiss Nutrition Societies.
Subject
Nutrition and Dietetics,General Medicine,Endocrinology, Diabetes and Metabolism,Medicine (miscellaneous)