Effects of the DASH vs. the Mediterranean Diet Combined With Salt Restriction on Blood Pressure Levels in Adults
Condition: Hypertension
MeSH terms: Hypertension
Study type: Interventional

Summary: 
      Non-pharmacological measures should serve as the first-line treatment in individuals with
      high normal blood pressure (BP) levels or grade 1 hypertension and low-moderate
      cardiovascular disease risk. Salt intake reduction and the dietary patterns of the Dietary
      Approaches to Stop Hypertension (DASH) diet and the Mediterranean diet (MedDiet) have been
      recognized as effective dietary measures for BP reduction. To the best of our knowledge, no
      clinical trials were designed to compare the effects of these dietary strategies. The purpose
      of the present trial was to compare the effects of salt restriction, the DASH, and the
      MedDiet combined with the salt restriction on BP levels and cardiometabolic risk factors in
      adults with high normal BP or grade 1 hypertension over 3 months.
    

Detailed description: 
      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.
    

Intervention name(s): Salt Restriction Group (SRG); DASH Diet combined with salt restriction Group (DDG); Mediterranean Diet combined with salt restriction Group (MDG)
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): Patients assigned to the SRG continued to consume their usual diet, but they had to restrict their sodium intake to 2,000 mg/ day. They were given a detailed booklet containing information about table salt, foods rich in sodium, and practical ways to decrease salt consumption. During each 45-min individual session, they received intensive counselling and training to increase adherence to salt restriction. Also, they were instructed to keep their body weight stable and not to change their physical activity level over the next 3 months.; Patients assigned to the DDG received a more extensive booklet, which which in addition to the information regarding salt restriction, contained detailed information about the DASH diet, and practical advice about how to start and stay on the assigned dietary pattern. In addition to the booklet, each patient received an individualized eating plan with six sample daily menus, incorporating the goals of the DASH diet. During the 45-min individual sessions, patients were intensively counselled and trained to increase adherence to salt restriction and the assigned dietary pattern. Also, they were instructed to keep their body weight stable and not to change their physical activity level over the next 3 months.; Patients assigned to the MDG received a more extensive booklet, which which in addition to the information regarding salt restriction, contained detailed information about the MedDiet, and practical advice about how to start and stay on the assigned dietary pattern. In addition to the booklet, each patient received an individualized eating plan with six sample daily menus, incorporating the goals of the MedDiet diet. During the 45-min individual sessions, patients were intensively counselled and trained to increase adherence to salt restriction and the assigned dietary pattern. Also, they were instructed to keep their body weight stable and not to change their physical activity level over the next 3 months.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Enrolled patients were blindly randomized with a 1:1:1:1 allocation 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).
Masking: Triple (Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Hypertension; Blood pressure; Diet; Salt; Dietary Approaches to Stop Hypertension; Mediterranean; Dietary pattern