Objective: To report selected dietary intake and vitamin status at baseline of volunteers participating in the ZENITH study and the correlation of vitamin status with zinc.
Design: A multicentre prospective intervention study employing a randomised double-blind design.
Setting: Clermont-Ferrand, Theix (France), Coleraine (Northern Ireland), Grenoble (France), Rome (Italy).
Participants: In total, 387 healthy middle-aged (55-70 y) and older (70-87 y) men and women participated in the study.
Methods: Dietary intake was assessed by means of a validated 4-d recall record. Fasting blood samples were simultaneously analysed for retinol and alpha-tocopherol by the HLPC method. Erythrocyte folates were measured by a competitive immunoassay with direct chemiluminescence detection on an automatised immunoanalyser.
Results: In all centres, men had a significantly (P < 0.0001) higher mean nutrient intake than women. Comparison between age-groups showed that older individuals had significantly lower intakes of macro- and selected micronutrients than middle-aged subjects (P < 0.0001). A high fat intake (from 36 to 40% of total energy) was observed in all examined groups. In relation to biochemical measures of vitamin status, all parameters were above their respective cut-off values for normality and, thus, none of the subjects had biochemical evidence of deficiency of these selected vitamins. A moderate correlation was found with plasma vitamin A and serum zinc (r = 0.12, P < 0.05) or red blood cell zinc (r = 0.12, P < 0.01) and with erythrocyte folates and red blood cell zinc (r = 0.11, P < 0.05).
Conclusions: There were only moderate differences in the nutrient intake of the ZENITH study volunteers among the four European centres. Their biochemical status for retinol, alpha-tocopherol and folate appeared adequate.