Effects of the DASH vs. the Mediterranean Diet Combined With Salt Restriction on Blood Pressure Levels in Adults

This was a 3‐month, single‐center, single‐blind, randomized, controlled, clinical trial, with 4 parallel groups. Before their randomization, the potential participants visiting the Hypertension Unit of the Hippocration General Hospital of Athens for the first time were assessed for eligibility during two screen visits. Anthropometric measurements, demographic characteristics, dietary intake, physical activity level, smoking history, and alcohol consumption were recorded. In addition, office and ambulatory BP measurements, as well as fasting blood samples and 24‐hour urine samples were obtained. Patients were eligible for inclusion if they had high normal BP (office systolic BP: 130‐139 mmHg and/or office diastolic BP: 85‐89 mmHg) or grade 1 hypertension (office systolic BP: 140‐159 mmHg and/or office diastolic BP: 90‐99 mmHg), based on the average of the means of the last two out of three measurements made during the two screen visits and were free of antihypertensive drug treatment and major medical conditions. Enrolled patients were blindly randomized to one of the four study groups, i.e., control group (CG), salt restriction group (SRG), DASH diet combined with salt restriction group (DDG), or MedDiet combined with salt restriction group (MDG). After randomization, all patients were followed monthly for 3 months in individual sessions, coordinated by the clinical dietician. For the patients of all four study groups, the goal was to maintain the initial body weight stable. Patients in the CG received the usual advice about salt restriction given to the patients by the clinical dietician at the Hypertension Unit. They were followed at the same frequency as the patients in the other study groups to obtain the study's intended measurements, without any other intervention. For the patients in the three intervention groups, the goal was to limit sodium intake to 2,000 mg/ day. Patients in the SRG were given a detailed booklet containing information about table salt and during each 45‐min individual session, they received intensive counselling and training to increase adherence to salt restriction. Patients in the DDG and the MDG received a more extensive booklet, which also contained information about the assigned dietary pattern and an individualized eating plan, while during the 45‐min individual sessions, patients in these two intervention groups were intensively counselled and trained to increase adherence to salt restriction and the assigned dietary pattern. Adherence to the assigned diet and/or salt restriction was established through subjective and objective measures, i.e., 7‐day food records, adherence scores, and 24‐hour urine tests. Anthropometric indices, dietary intake, physical activity level, and office BP were measured at baseline, and during each follow‐up visit. Ambulatory BP measurements and collection of fasting blood samples and 24‐hour urine samples were conducted at baseline and the end of the 3‐month intervention.