The lower vitamin C plasma concentrations in elderly men compared with elderly women can partly be attributed to a volumetric dilution effect due to differences in fat-free mass.
Women show higher vitamin C plasma concentrations than men, but the reasons for this observation still require elucidation. The objective of the present study was to investigate whether sex differences in vitamin C plasma concentrations are present in elderly subjects and whether these differences are due to sex-specific lifestyles, total antioxidant status (TAOS) and/or body composition. Fasting plasma concentrations of vitamin C were assessed by photometric detection in a cross-sectional study of 181 women and eighty-nine men aged 62-92 years. Body composition was determined by bioelectrical impedance analysis. Vitamin C intake was assessed with a 3 d estimated dietary record. Stepwise multiple regression analyses were performed to investigate whether sex is an independent predictor of vitamin C plasma concentrations by controlling for age, vitamin C intake, lifestyle factors, TAOS and body composition. Women showed higher vitamin C plasma concentrations than men (76 v. 62 μmol/l, P< 0·0001). In the multiple regression analysis, male sex was a negative predictor of vitamin C plasma concentrations (β = -0·214), as long as absolute fat-free mass (FFM) was not considered as a confounder. When absolute FFM was included, sex was no longer a predictor of vitamin C plasma concentrations, whereas absolute FFM (β = -0·216), physical activity level (β = 0·165), intake of vitamin C supplements (β = 0·164), age (β = 0·147) and smoking (β = -0·125) affected vitamin C plasma concentrations. The results indicate that a higher absolute FFM, and thus a higher distribution volume of vitamin C, contributes to lower vitamin C plasma concentrations in men than women.
Institute of Nutritional Science, Justus-Liebig-University,Goethestrasse 55,D-35390Giessen,Germany.
Alexandra
A
Jungert
Institute of Nutritional Science, Justus-Liebig-University,Goethestrasse 55,D-35390Giessen,Germany.
Monika
M
Neuhäuser-Berthold
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001205:Ascorbic Acid / Q000097:blood* / Q000627:therapeutic use; D001206:Ascorbic Acid Deficiency / Q000097:blood / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D001824:Body Constitution; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D015536:Down-Regulation; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D015995:Prevalence; D015203:Reproducibility of Results; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects
D001205:Ascorbic Acid
Fat-free mass