Mediterranean Diet and Metabolic Syndrome: a dietary intervention study to reduce metabolic syndrome risk after heart transplantation.

Background: heart-transplanted (HTx) patients are inclined to develop the Metabolic Syndrome (MetS), mainly due to the side effects of immunosuppressive therapy. The Mediterranean Diet (MD) has proven effective preventing MetS in general population. Aim: to assess the impact of a dietary intervention based on MD in HTx patients with high risk of MetS. Methods: 21 HTx patients were enrolled and randomly assigned in an intervention (IG) or in a control group (CG). IG received personalised dietary advices based on MD along 3 meetings (baseline, at 6 and 12 months). CG received general dietary indications based on Italian guidelines for a healthy nutrition at baseline (1). A validated 15-item questionnaire (2) was administered to assess the MD adherence, at each timepoint to IG and at baseline and after 6 months to CG. The MD score ranged from 0 to 9 (minimal-maximal adherence). Data on MetS criteria were collected from clinical informatic system (study approved by the Ethics Committee of Friuli Venezia Giulia Region). Results: 11 patients were included in IG and 10 in CG. At baseline, 46% patients of the IG resulted affected by MetS vs 20% of the CG (p=0.221). IG patients showed more hypertriglyceridemia (100% vs 70%, p=0.09), while the other MetS criteria were comparable. MD score was low and similar between groups (4±2 vs 4±2, p=0.918). At 6 months, MD score of IG become higher than CG (5±2 vs 4±1, p=0.169) and blood pressure (BP) expressed in mmHg (median, 25th-75th) resulted significantly lower (systolic BP 130, 120–130 vs 145, 130–147, p=0.020; diastolic BP 80, 75–80 vs 86, 83–90, p=0.004). In addition, fasting glucose (84±10mg/dL vs 94±18mg/dL, p=0.133) and triglycerides (87±38mg/dL vs 113±41mg/dL, p=0.153) were found lower in IG. At 12 months, in IG adherence to MD increased significantly compared with the baseline (7±1.3 vs 4±1.5, p=0.001) and waist circumference was reduced on average of 1.3±2.6 cm. Conclusions: despite the small sample size due to COVID-19, the dietary intervention providing specific dietary advices based on MD principles, may exert many beneficial effects on MD adherence and MetS criteria of HTx patients. 1. CREA, 2018. 2. Gnagnarella P., Nutr. Metab. Cardiovasc., 2018, 28: 1140-1147.