Epidemiological research is progressing towards digital data collection. This study aimed to evaluate the validity and reproducibility of our new, computerized, and easy-to-use Food Frequency Questionnaire (FFQ).

Dietary intake was assessed using 24-hours Dietary Recalls (DR) and our FFQ, consisting of 133 food items and beverages. The software allows users to choose between three visualized portion sizes, categorizes the selections into food groups with three degrees of food processing levels, and produces a visualized output of the results. The reproducibility of the FFQ was evaluated based on two user submissions, and its validity was measured by comparing the calculated caloric intake and macro and micro-nutrient consumption to the mean values from three 24-hour DRs. Thirty women of fertility age (18-45) were recruited for the study, of whom 27 qualified for reproducibility testing and 23 qualified for validity testing.

The FFQs yielded higher nutrient intakes than the 24-hours DRs without significant difference for most nutrients (<10%; good agreement), except for Calcium and Magnesium (>10%; acceptable agreement), based on a Wilcoxon signed-rank test (p < 0.05). Spearman’s correlation coefficient showed a moderate (Vitamin B12 and Folate) to strong (Energy) correlation (p<0.05). The Intra Class Correlation (ICC) coefficient between the two FFQs ranged from moderate for Calcium (0.55) to high for Magnesium (0.83) (p<0.05), indicating good reproducibility. Evaluation of food groups and processed food reproducibility scores yielded ICC coefficients ranging from moderate (0.53; super-processed foods) to high (0.83; non-processed foods) (p<0.05). Spearman’s correlations coefficient showed a moderate (sugar-sweetened beverages) to strong (non-processed foods) correlation (p<0.05).

The FFQ we developed and validated in this study showed moderate to high reproducibility and moderate validity in a group of thirty women of fertility age. Moreover, it is highly adjustable and easy to use, and its digital-based delivery enables large-scale, multilingual nutritional research.