Effect of the Mediterranean diet on blood pressure in the PREDIMED trial: results from a randomized controlled trial

Abstract

BackgroundHypertension can be prevented by adopting healthy dietary patterns. Our aim was to assess the 4-year effect on blood pressure (BP) control of a randomized feeding trial promoting the traditional Mediterranean dietary pattern.MethodsThe PREDIMED primary prevention trial is a randomized, single-blinded, controlled trial conducted in Spanish primary healthcare centers. We recruited 7,447 men (aged 55 to 80 years) and women (aged 60 to 80 years) who had high risk for cardiovascular disease. Participants were assigned to a control group or to one of two Mediterranean diets. The control group received education on following a low-fat diet, while the groups on Mediterranean diets received nutritional education and also free foods; either extra virgin olive oil, or nuts. Trained personnel measured participants’ BP at baseline and once yearly during a 4-year follow-up. We used generalized estimating equations to assess the differences between groups during the follow-up.ResultsThe percentage of participants with controlled BP increased in all three intervention groups (P-value for within-group changes: P<0.001). Participants allocated to either of the two Mediterranean diet groups had significantly lower diastolic BP than the participants in the control group (−1.53 mmHg (95% confidence interval (CI) −2.01 to −1.04) for the Mediterranean diet supplemented with extra virgin olive oil, and −0.65 mmHg (95% CI -1.15 to −0.15) mmHg for the Mediterranean diet supplemented with nuts). No between-group differences in changes of systolic BP were seen.ConclusionsBoth the traditional Mediterranean diet and a low-fat diet exerted beneficial effects on BP and could be part of advice to patients for controlling BP. However, we found lower values of diastolic BP in the two groups promoting the Mediterranean diet with extra virgin olive oil or with nuts than in the control group.Trial registrationCurrent Controlled Trials ISRCTN35739639

Associations between Dietary Patterns and Blood Pressure in a Clinical Sample of Overweight Adults

“…Likewise, consumption of nuts was significantly inversely associated with hypertension (RR: 0.66; 95% CI: 0.44, 1.00; P = 0.049) in a recent meta-analysis of four prospective studies [12]. Dietary patterns such as the DASH diet [19], the Mediterranean diet [21] and the Nordic diet [41] have been shown to reduce BP. In our previous research, a meta-analysis of 17 randomized controlled trials showed that a dietary pattern that was rich in fruits, vegetables, wholegrains, legumes, nuts, seeds, dairy and fish and low in processed foods and red meat reduced SBP and DBP by 4.06 mmHg and 2.30 mmHg, respectively [42].…”

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“…dietary-induced BP decreases that in turn will reduce the risk of adverse cardiovascular event (28).…”

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“…§ Mixed nuts ¼ almonds, pistachios, walnuts, groundnuts, hazelnuts, pecans, cashews and macadamias. (52) (83) 4 years n 7158 (control ¼ 2064, OO ¼ 2345, nuts ¼ 2065), M and F, risk of CVD, mean 67 (SD 6) years (86) 4 weeks per arm fasting glucose or insulin (48,63 -76) . One study that failed to achieve an improvement in insulin sensitivity supplemented participants' diets with 100 g almonds/d for 4 weeks.…”