Raised blood pressure (BP) levels is the leading cause of death globally. Essential Hypertension (EH) is a major risk factor for cardiovascular events. Lifestyle modification is an important component of EH therapy. The aim of this parallel, randomized controlled study was to examine the effect of a 6-month intensive nutritional treatment compared to the usual care and to correlate that with the levels of BP, the endothelial and the vascular function. To this end, we enrolled 91 newly diagnosed, according to the European Society of Hypertension (ESH) criteria, adult patients with early stage 1 EH. Primary outcomes included measurements of BP and central hemodynamics. endothelial dysfunction (Asymmetric Dimethylarginine), carotid intima media-thickness (IMT), carotid stiffness (β-stiffness factor/ carotid PWV), biochemical and 24-h urine profile. Secondary outcomes included dietary analysis, anthropometry, physical activity (PA) and Basal Metabolic Rate. In total 81 Patients were randomized and divided into two groups. In the first group (n=41) participants acted as controls, receiving standard advise concerning lifestyle modifications. The second group formed the intervention group (n=40), receiving intensive lifestyle treatment. Out of the 81 patients randomized in total, five patients were excluded from the analyses due to Goldberg criterion for misreporting energy intake. Thus, a total of 38 patients formed the samples in each group. Among patients in the intervention group, post-treatment BP (office and 24h), was significantly improved compared to the baseline (p < 0,001), and to the control group (p<0,05) at the end of the six months period. Central BP was also improved in the intervention group, compared to the control group, according to the 24h measurements (p=0,02 and p=0,011, respectively) and to the daytime records (p=0,001 and p=0,012, for SBP and DBP respectively). Six months of intensive treatment was efficient in improving ADMA levels (p<0,001). When compared to the standard care group, intensive intervention participants improved ADMA levels (p<0,001), cIMT (p=0,046), β-stiffness index (p=0,007) and carotid PWV (p=0,007). In the intensive treatment group, a significant improvement in the lipidemic profile, as well as in the urinary Na losses at the end of the treatment was noted compared to the controls (p<0,001 for total cholesterol and Na urinary losses, p<0,05 for triglycerides and LDL). Somatometry in the intervention group showed a reduction in all indices (weight, circumferences, FFM, FM) at the end of treatment, compared to baseline (p<0,001). The intensive treatment group at the end of the period improved Dietary Inflammatory Index (p=0,027), MedDiet and Salt score (p<0,001), when compared with the control group. Multivariate analysis revealed that variations in the ADMA levels can be explained indepedently and positively by the DII alterations and changes in the MedDiet score are related significantly and negatively with variations in the intensive treatment group for 24-h and day peripheric…