Validation of the food compass score through 24 h recalls and measurement of erythrocyte fatty acids in a mediterranean population

The Food Compass Score (FCS) is a newly introduced Nutrient Profiling System for assessing overall diet quality. Its validation against dietary intake and objective biomarkers is limited. This study aimed to validate the FCS using 24-hour recalls, erythrocyte fatty acids, a long-term biomarker of fatty acids intake, and MedDietScore as a healthiness index. Apparently healthy subjects were recruited. Two 24 h-recalls and a food-frequency questionnaire were administered. Erythrocyte fatty acids were determined by gas chromatography. Energy adjusted Spearman correlations were performed. In addition, simple and age/sex/BMI adjusted linear regression models were applied with FCS as dependent and energy-adjusted nutrients or biomarkers as independent variables. One hundred and six subjects (48 men, 44 ± 13 years; 58 women, 44 ± 14 years) participated. The mean FCS of the study participants was 55.9 ± 9.5. In fully adjusted models the FCS was positively associated with % monounsaturated fatty acids (% of total energy intake) (B = 0.401, 95% CI:0.170–0.632, p = 0.001), % fat (% of total energy intake) (B = 0.230, 95% CI:0.036–0.425, p = 0.02), vitamin C (B = 0.022, 95% CI:0.005–0.038, p = 0.01), ɑ-tocopherol (B = 0.427, 95% CI:0.0070–0.785, p = 0.02), vitamin K (B = 5.225, 95% CI:1.670–8.840, p = 0.005), potassium intakes (B = 0.002, 95% CI:0.0008–0.004, p = 0.04), and the MedDietScore (B = 0.805, 95% CI:0.473–1.137, p < 0.001). It was also negatively associated with % carbohydrate intake (% of total energy intake) (B = − 0.209, 95% CI: − 0.391 to − 0.027, p = 0.025). In addition, the FCS was associated with unsaturated/ SFA ratio, dietary fiber/carbohydrate ratio, and potassium/sodium ratio after adjustment for age, sex, BMI and energy intake. The FCS was positively associated with the % erythrocyte EPA (B = 13.814, 95% CI:5.632–21.996, p = 0.001), DHA (B = 1.769, 95% CI:0.332–3.205, p = 0.01), omega-3 fatty acids (B = 1.380, 95% CI:0.333–2.428, p = 0.01) and the omega-3 index (B = 1.581, 95% CI: 0.358–2.805, p = 0.01). The correlations of the FCS with the MedDietScore, nutrients and erythrocyte fatty acids investigated suggest that FCS is a valid index encouraging its use for clinical and consumer guidance.