A recent study published in ‘Science Direct’ reveals a novel method to approach a per protocol analysis with a balanced compliance assessment in larger multicentre dietary trials. The study aimed to characterize a multicenter randomized controlled trial with a healthy Nordic diet (HND) (Nordic diet features foods that are locally sourced or traditionally eaten in Denmark, Finland, Iceland, Norway, and Sweden. Developed in collaboration with the acclaimed Copenhagen gourmet restaurant NOMA, the diet emphasizes the use of seasonal, healthy, regional foods.) compared to a Control diet (CD) by plasma and urine metabolic profiles and to associate them with cardiometabolic markers.

During 18–24 weeks of intervention, 200 participants with metabolic syndrome were advised to consume either HND (e.g. whole-grain products, berries, rapeseed oil, fish and low-fat dairy) or CD while being weight stable. Metabolic profiles of fasting plasma and 24h pooled urine were analyzed to identify characteristic diet-related patterns. Principal components analysis (PCA) scores (i.e. PC1 and PC2 scores) were used to test their combined effect on blood glucose response (primary endpoint), serum lipoproteins, triglycerides, and inflammatory markers.

Plasma and urine metabolite profiles from SYSDIET reflected good compliance with dietary recommendations across the region. The scores of metabolites characterizing the diets associated with outcomes related to cardio-metabolic risk. The results, therefore, shed insights into the utilization of HND in multicentre dietary trials.