Validation of recalled food intake in the past in a Japanese population

To evaluate the validity of the recall method in estimating food intake in the distant past, we assessed past and current food intakes by mailed food questionnaires among 80 residents in Gifu, Japan who had answered the same questionnaire 9 years ago. We compared rank correlations and differences between recalled food intake scores and past ones with those between current food intake scores and past ones. We observed higher scores of recalled intake for meat, potatoes and alcohol, and a lower score of recalled intake for cereals than the scores of past intake. We observed increase in food intake scores of soyabean products, dairy products and potatoes and decrease in that of cereals intakes from past to current. The rank correlation coefficients between the recalled and past food intake scores (r = 0.24-0.89) were greater than those between the current and past ones (r = 0.10-0.70) for every food item except for dairy products. After stratification by sex, age and degree of change in body mass index (BMI), the greater correlation between the recalled and past food intake scores remained. These findings suggest that the recall method is more preferable than the current data to estimate food intake in the distant past in Japan.