Vitamin E content of foods: comparison of results obtained from food composition tables and HPLC analysis.
BACKGROUND & AIMS: Data on vitamin E content of foods are essential for nutrition research and its application. The aim of this study was to investigate the precision of calculated vitamin E content of prepared meals. METHODS: The vitamin E content of 69 dishes of a menu cycle sampled at two occasions were calculated using 4 different food composition tables (FCT) and measured by HPLC. RESULTS: Data were complete for 50-69 dishes. The proportion of dishes with differences between FCTs < or = 20% were 17-100%. Differences between HPLC and the Souci-Fachmann-Kraut table were < or = 20% in 8/46 dishes for alpha- and in 14/46 dishes for gamma-tocopherol. Differences fell in the order of baked > raw > fried/roasted > boiled > mixed prepared foods. The 2 samplings taken 6 months apart showed considerable differences. CONCLUSIONS: There are substantial differences in calculated/measured vitamin E content of prepared foods: (i) between different FCTs; (ii) between FCTs and HPLC, and (iii) between different seasons. This can be explained by intrinsic variability (breeding, season, country of origin, ripeness, freshness) and food processing, as well as selection of FCTs and should be taken into account when interpreting data of dietary intervention studies.