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

Randomized crossover trial in 41 community-dwelling Australian adults aged 45 to 75 years at risk of cardiovascular disease and not currently following a Mediterranean diet. Participants were recruited in metropolitan Adelaide and completed both the MedDairy diet and a low-fat control diet in separate 8-week phases.

The MedDairy phase used a Mediterranean-style diet adapted to meet Australian calcium guidelines, with three or more weekly servings of fish and seafood, five or more weekly servings of nuts or seeds, extra virgin olive oil as the main cooking fat, ad libitum whole grains, vegetables, eggs, and select white meats, and limited red and processed meats. Participants also consumed three to four dairy servings per day to provide about 900 to 1200 mg calcium per day; the comparator was a low-fat diet with restricted fats and avoidance of high-fat foods. Each diet phase lasted 8 weeks in a crossover design.

The MedDairy diet improved several cardiovascular risk markers versus the low-fat diet and was considered feasible in this Australian population. It significantly lowered morning home systolic and diastolic blood pressure, clinic systolic blood pressure, total triglycerides, and the total cholesterol to HDL cholesterol ratio, while increasing HDL cholesterol and lowering afternoon heart rate. There were no clear changes in glucose, insulin, CRP, HOMA indices, or Framingham Risk Score. Participants also met calcium recommendations during MedDairy, with mean calcium intake about 1284 mg/day, but low-fat diet favored fat mass reduction and lean mass gain.

The trial was small, single-center, and short term, with only 8-week intervention phases and modest completion numbers across the crossover periods. Results may not generalize beyond older Australian adults at cardiovascular risk, and adverse events were not reported. Physical activity was also not reported, limiting interpretation of body composition and cardiometabolic changes.