Relative validity of a Meal-based Diet History Questionnaire against a four-day weighed dietary record for assessing total and meal-specific amino acid intake in Japanese adults

This study aimed to develop an amino acid composition table for Japanese foods and evaluate the relative validity of the Meal-Based Diet History Questionnaire (MDHQ) in estimating total and meal-specific amino acid intake, using a four-day weighed dietary record (DR) as the reference. A total of 111 Japanese women and 111 Japanese men completed both online and paper MDHQs, along with a 4-day non-consecutive DR. The amino acid composition table was constructed based on the Standard Tables of Food Composition in Japan 2020. Median amino acid intakes estimated by the online MDHQ were generally lower than those from the DR across all calculation methods (crude, residual, density, and %protein) in both sexes, with significant differences observed for most of the 18 amino acids. Median Spearman correlation coefficients between the online MDHQ and DR for total amino acid intake were 0.43-0.44 in women and 0.31-0.37 in men. Concordance correlation coefficients (CCCs) were lower than the corresponding Spearman coefficients, and Bland-Altman analyses showed wide limits of agreement with proportional bias. Similar findings were observed for the paper MDHQ. In conclusion, the MDHQ showed limited relative validity for ranking total and individual amino acid intakes at main meals, with weaker performance for snacks and limited ability to estimate absolute individual intakes. Despite these limitations, the MDHQ provides a novel approach for examining meal-specific dietary patterns and may offer useful insights in epidemiological studies when its limitations are appropriately considered.