Validity of a Short Food Frequency Questionnaire for Toddlers of NELA Birth Cohort Study

Background/Objectives: Our aim was to evaluate the reproducibility and validity of a semi-quantitative food frequency questionnaire (FFQ) for the assessment of usual nutrient and food intakes in children of 18 months old. Methods: We included 103 toddlers aged 18 months from the Nutrition in Early Life and Asthma (NELA) birth cohort study. A 47-item FFQ was administered twice to parents with a 3-month interval. During that period, we also performed three non-consecutive 24 h dietary recalls (24hDRs) and oral mucosa samples for determining the fatty acid profile (glycerophospholipids). We estimated correlation coefficients of reproducibility for nutrient and food group intakes by comparing both FFQs and validity coefficients by comparing nutrient intakes between the second FFQ and the average of the three 24hDRs. We also explored biochemical validity by comparing the intake of fish from the FFQ with the percentage of fatty acids in oral mucosa cells. Results: The average of correlation coefficients for FFQ reproducibility was r = 0.48 for energy-adjusted nutrient intakes (ranging from r = 0.28 for Na to r = 0.62 for Mg and Zn) and r = 0.35 for the intake of energy-adjusted food groups. The average correlation coefficient for FFQ validity on nutrient intakes was r = 0.48, ranging from r = 0.16 for alpha-carotene to r = 0.75 for vitamin E. We also found a positive correlation between total omega-3 fatty acids and docosahexaenoic acid percentages in oral mucosa cells and the intake of total and white fish, r = 0.31 and r = 0.34, respectively. Conclusions: This study shows that our short FFQ demonstrated moderate reproducibility (mean r = 0.48) and validity (mean r = 0.48) for dietary assessment of most nutrients and foods in 18-month-old children in Spain. This FFQ provides an efficient and minimally invasive method for evaluating toddler dietary intake, particularly in Mediterranean contexts.