Nutrient scoring for the DEGS1-FFQ – from food intake to nutrient intake

Background: While necessary for studying dietary decision-making or public health, estimates of nutrient supply based on self-reported food intake are barely accessible or fully lacking and remain a challenge in human research. In particular, detailed information on dietary fiber is limited. In this study we introduce an automated openly available approach to assess self-reported nutrient intake for research purposes for a popular, validated German food frequency questionnaire (FFQ). Methods: To this end, we i) developed and shared a code for assessing nutrients (carbohydrates, fat, protein, sugar, fiber.) for 53 items of the quantitative, validated German DEGS1-FFQ questionnaire implementing expert-guided nutritional values of diverse sources with several raters. In a sample of individuals (nGUT-BRAIN = 61 (21 female) overweight, omnivorous), we ii) cross-validated nutrient intake of the last 7 days and the last 24 hours and iii) computed test-retest reliability across two timepoints. Further, iv) we report newly computed nutrient intake for two independent cross-sectional cohorts with continuous weight status and different dietary habits (nMensa= 134 (79 female, 1 diverse), nGREADT = 76 male). Exploratively, we correlated computed nutrient intake with v) anthropometric and vi) blood-based biomarkers. Results: In overweight adults (n= 61 (21 female), mean age 28.2±6.5 years, BMI 27.4±1.6 kg/m2) nutrient intakes were mostly normally distributed and within or surpassing recommended reference nutrient ranges for both last 7 days and last 24 hours. Reliability between last 7 days and 24 hours per visit was moderate (Pearson’s rall≥ 0.34, pall < 0.001, rmax = 0.54) and absolute agreement across two timepoints was moderate for 7 days (kappaall > 0.40, pall < 0.001) and poor for 24 hours (kappaall> 0.08, pall < 0.001). Associations of dietary components to anthropometric markers showed distinct sex differences, with overall higher intake by males compared to females and opposite associations of fiber ...