A Short Questionnaire for Evaluating Mediterranean Diet Adherence and Nutritional Sustainability: Validation in Turkish Adults

Abstract

Objective

This study aimed to evaluate the validity and reliability of the Turkish version of the Short Questionnaire for the Evaluation of Adherence to the Mediterranean Diet and Nutritional Sustainability (MedQ-Sus), which excludes alcohol consumption and simultaneously assesses adherence to the Mediterranean diet and a sustainable diet, in adults.

Methods

The study included 138 adults, of whom 39.9% were male and 60.1% were female, with a mean age of 34.3 ± 12.7 years. The MedQ-Sus is a brief questionnaire that generates a Mediterranean Diet score and a Sustainable Diet score from the same eight food-group consumption data using different scoring criteria. Dietary intake was assessed using 3-day food records. Validity was evaluated by comparing the MedQ-Sus scores with corresponding food-group and nutrient intakes derived from the food records and by examining construct validity using a modified alternate Mediterranean Diet score (aMED) and the Planetary Health Diet Index (PHDI). Associations and agreement were assessed using Spearman correlation coefficients, Bland–Altman analysis, and intraclass correlation coefficients (ICCs) based on absolute agreement, as appropriate. Test–retest reliability was evaluated in 71 randomly selected participants 4 weeks after the initial administration.

Results

Statistically significant and positive correlations were found between the consumption levels of all food groups associated with the Mediterranean Diet score components. The Sustainable Diet score showed positive correlations with all food groups except legumes and fresh fruits (p < 0.05). The strongest relationship for both the Mediterranean Diet score (r = 0.490) and the Sustainable Diet score (r = 0.488) was observed in the consumption of fish and fish products (p < 0.001). Bland–Altman analysis indicated an acceptable level of agreement between the MedQ-Sus scores and the corresponding estimates derived from the food records. As adherence levels measured by the MedQ-Sus increased, intakes of fish, olive oil, dietary fibre, magnesium, zinc, monounsaturated fatty acids, and omega-3 fatty acids increased, whereas polyunsaturated fatty acid intake decreased. In the test–retest analysis, strong positive correlations were observed for the Mediterranean Diet score (r = 0.782) and the Sustainable Diet score (r = 0.813) (both p < 0.001).

Conclusion

The MedQ-Sus demonstrated good validity and reliability as a practical screening tool for simultaneously assessing adherence to the Mediterranean diet and adherence to a sustainable diet among the adults included in this study, while its exclusion of alcohol consumption may support its use across different adult population groups.