Mixed
A machine-readable Food Frequency Questionnaire (FFQ) provides nutrient intake estimates with validity comparable to a 7-day diet diary (7DD) when validated against biomarkers, making it a suitable tool for ranking individuals in large-scale epidemiological studies despite systematic biases in absolute intake estimation.
For large-scale health tracking where absolute precision is less critical than identifying trends and relative intake, a standardized Food Frequency Questionnaire is a valid and efficient tool. It correlates well with biological markers (like fatty acids and vitamins) similarly to more burdensome 7-day diaries, making it suitable for population-level insights without requiring daily logging.
Against the available biomarkers, the machine-readable FFQ performed well in comparison with the manually coded 7DD in this study population.
Why this rating
Cross-sectional study with objective biomarker validation (CEFA, plasma vitamins) in a large, stratified sample (n=860), though self-report bias remains a limitation.
Source
Dietary assessment in Whitehall II: comparison of 7 d diet diary and food-frequency questionnaire and validity against biomarkers
Eric J. Brunner et al. · British Journal Of Nutrition · 2001
DOI 10.1079/bjn2001414
More from this paper
- Energy-adjusted nutrient intake analysis is the optimal method for presenting and analyzing dietary data in epidemiological studies, as it reduces bias from low energy reporting and eliminates confounding by total energy intake.Good
- Food Frequency Questionnaires (FFQ) tend to overestimate plant-derived micronutrients (like carotenes) and underestimate fat intake compared to 7-day diet diaries, but these systematic biases do not necessarily invalidate their ability to rank individuals for epidemiological purposes.Good
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