A Mediterranean diet supplemented with dairy foods improves markers of cardiovascular risk: Results from the MedDairy randomized controlled trial

Background: The Mediterranean diet (MedDiet) offers benefits to cardiovascular health but may not meet Western recommendations for calcium and dairy intake, which could impede long-term adoption. Objective: The current study aimed to determine the effect of a MedDiet supplemented with dairy foods on cardiovascular risk factors. Design: A randomized, controlled, crossover design compared a MedDiet with 3-4 daily servings of dairy (MedDairy) and a low-fat (LF) control diet. Forty-one participants aged ≥45 y and at risk of cardiovascular disease (CVD) were randomly allocated to their first intervention, either the MedDairy or LF diet. Participants followed each intervention for 8 wk, and an 8-wk washout period separated interventions. The primary outcome was home-measured systolic blood pressure (SBP) assessed in the morning, afternoon, and evening. Secondary outcomes included clinic-measured blood pressure (morning), body composition, blood lipids, C-reactive protein (CRP), plasma glucose, serum insulin, and the Framingham Risk Score. Results: Compared with the LF intervention, the MedDairy intervention resulted in a significantly lower morning SBP (mean difference: −1.6 mm Hg; 95% CI: −2.8, −0.4 mm Hg; P = 0.01), lower morning diastolic blood pressure (mean difference: −1.0; 95% CI: −1.7, −0.2 mm Hg; P = 0.01) and clinic SBP (mean difference: −3.5 mm Hg; 95% CI: −6.4, −0.7 mm Hg; P = 0.02), significantly higher HDL cholesterol (mean difference: 0.04 mmol/L; 95% CI: 0.01, 0.06 mmol/L; P < 0.01), lower triglycerides (mean difference: = −0.05 mmol/L; 95% CI: −0.08, −0.01 mmol/L; P < 0.01), and lower ratio of total to HDL cholesterol (mean difference: −0.4; 95% CI: −0.6, −0.2; P < 0.001). No effects were observed for other outcome measures. Conclusions: Following a MedDiet with additional dairy foods led to significant changes in markers of cardiovascular risk over 8 wk. The MedDiet supplemented with dairy may be appropriate for an improvement in cardiovascular risk factors in a population at risk of CVD.