HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Rautiainen, S. Articles by Wolk, A. PubMed PubMed Citation Articles by Rautiainen, S. Articles by Wolk, A. Agricola Articles by Rautiainen, S. Articles by Wolk, A.

The validity and reproducibility of food-frequency questionnaire–based total antioxidant capacity estimates in Swedish women ^1,2,3

¹ From the Division of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden (SR and AW); the Antioxidant Research Laboratory at the Unit of Human Nutrition, National Institute for Food and Nutrition Research, Rome, Italy (MS); the Division of Biochemical Toxicology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden (RM); and the US Department of Agriculture, Agriculture Research Service, Arkansas Children's Nutrition Center, Little Rock, AR (RLP)

Background: Total antioxidant capacity (TAC) provides an assessment of antioxidant activity and synergistic interactions of redox molecules in foods and plasma.

Objective: We investigated the validity and reproducibility of food-frequency questionnaire (FFQ)–based TAC estimates assessed by oxygen radical absorbance capacity (ORAC), total radical-trapping antioxidant parameters (TRAP), and ferric-reducing antioxidant power (FRAP) food values.

Design: Validity and reproducibility were evaluated in 2 random samples from the Swedish Mammography Cohort. Validity was studied by comparing FFQ-based TAC estimates with one measurement of plasma TAC in 108 women (54–73-y-old dietary supplement nonusers). Reproducibility was studied in 300 women (56–75 y old, 50.7% dietary supplement nonusers) who completed 2 FFQs 1 y apart.

Results: Fruit and vegetables (mainly apples, pears, oranges, and berries) were the major contributors to FFQ-based ORAC (56.5%), TRAP (41.7%), and FRAP (38.0%) estimates. In the validity study, whole plasma ORAC was correlated (Pearson) with FFQ-based ORAC (r = 0.35), TRAP (r = 0.31), and FRAP (r = 0.28) estimates from fruit and vegetables. Correlations between lipophilic plasma ORAC and FFQ-based ORAC, TRAP, and FRAP estimates from fruit and vegetables were 0.41, 0.31, and 0.28, and correlations with plasma TRAP estimates were 0.31, 0.30, and 0.28, respectively. Hydrophilic plasma ORAC and plasma FRAP values did not correlate with FFQ-based TAC estimates. Reproducibility, assessed by intraclass correlations, was 0.60, 0.61, and 0.61 for FFQ-based ORAC, TRAP, and FRAP estimates, respectively, from fruit and vegetables.

Conclusions: FFQ-based TAC values represent valid and reproducible estimates that may be used in nutritional epidemiology to assess antioxidant intake from foods. Further studies in other populations to confirm these results are needed.