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The effect of tree nut, peanut, and soy nut consumption on blood pressure: a systematic review and meta-analysis of randomized controlled clinical trials.
Mohammadifard, N, Salehi-Abargouei, A, Salas-Salvadó, J, Guasch-Ferré, M, Humphries, K, Sarrafzadegan, N
The American journal of clinical nutrition. 2015;(5):966-82
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Abstract
BACKGROUND Although several studies have assessed the effects of nut consumption (tree nuts, peanuts, and soy nuts) on blood pressure (BP), the results are conflicting. OBJECTIVE The aim was to conduct a systematic review and meta-analysis of published randomized controlled trials (RCTs) to estimate the effect of nut consumption on BP. DESIGN The databases MEDLINE, SCOPUS, ISI Web of Science, and Google Scholar were searched for RCTs carried out between 1958 and October 2013 that reported the effect of consuming single or mixed nuts (including walnuts, almonds, pistachios, cashews, hazelnuts, macadamia nuts, pecans, peanuts, and soy nuts) on systolic BP (SBP) or diastolic BP (DBP) as primary or secondary outcomes in adult populations aged ≥18 y. Relevant articles were identified by screening the abstracts and titles and the full text. Studies that evaluated the effects for <2 wk or in which the control group ingested different healthy oils were excluded. Mean ± SD changes in SBP and DBP in each treatment group were recorded for meta-analysis. RESULTS Twenty-one RCTs met the inclusion criteria. Our findings suggest that nut consumption leads to a significant reduction in SBP in participants without type 2 diabetes [mean difference (MD): -1.29; 95% CI: -2.35, -0.22; P = 0.02] but not in the total population. Subgroup analyses of different nut types suggest that pistachios, but not other nuts, significantly reduce SBP (MD: -1.82; 95% CI: -2.97, -0.67; P = 0.002). Our study suggests that pistachios (MD: -0.80; 95% CI: -1.43, -0.17; P = 0.01) and mixed nuts (MD: -1.19; 95% CI: -2.35, -0.03; P = 0.04) have a significant reducing effect on DBP. We found no significant changes in DBP after the consumption of other nuts. CONCLUSIONS Total nut consumption lowered SBP in participants without type 2 diabetes. Pistachios seemed to have the strongest effect on reducing SBP and DBP. Mixed nuts also reduced DBP.
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Mediterranean diet reduces 24-hour ambulatory blood pressure, blood glucose, and lipids: one-year randomized, clinical trial.
Doménech, M, Roman, P, Lapetra, J, García de la Corte, FJ, Sala-Vila, A, de la Torre, R, Corella, D, Salas-Salvadó, J, Ruiz-Gutiérrez, V, Lamuela-Raventós, RM, et al
Hypertension (Dallas, Tex. : 1979). 2014;(1):69-76
Abstract
UNLABELLED The PREvención con DIeta MEDiterránea (PREDIMED) trial showed that Mediterranean diets (MedDiets) supplemented with either extravirgin olive oil or nuts reduced cardiovascular events, particularly stroke, compared with a control, lower fat diet. The mechanisms of cardiovascular protection remain unclear. We evaluated the 1-year effects of supplemented MedDiets on 24-hour ambulatory blood pressure (BP), blood glucose, and lipids. Randomized, parallel-design, controlled trial was conducted in 2 PREDIMED sites. Diets were ad libitum, and no advice on increasing physical activity or reducing sodium intake was given. Participants were 235 subjects (56.5% women; mean age, 66.5 years) at high cardiovascular risk (85.4% with hypertension). Adjusted changes from baseline in mean systolic BP were -2.3 (95% confidence interval [CI], -4.0 to -0.5) mm Hg and -2.6 (95% CI, -4.3 to -0.9) mm Hg in the MedDiets with olive oil and the MedDiets with nuts, respectively, and 1.7 (95% CI, -0.1 to 3.5) mm Hg in the control group (P<0.001). Respective changes in mean diastolic BP were -1.2 (95% CI, -2.2 to -0.2), -1.2 (95% CI, -2.2 to -0.2), and 0.7 (95% CI, -0.4 to 1.7) mm Hg (P=0.017). Daytime and nighttime BP followed similar patterns. Mean changes from baseline in fasting blood glucose were -6.1, -4.6, and 3.5 mg/dL (P=0.016) in the MedDiets with olive oil, MedDiets with nuts, and control diet, respectively; those of total cholesterol were -11.3, -13.6, and -4.4 mg/dL (P=0.043), respectively. In high-risk individuals, most with treated hypertension, MedDiets supplemented with extravirgin olive oil or nuts reduced 24-hour ambulatory BP, total cholesterol, and fasting glucose. CLINICAL TRIAL REGISTRATION URL http://www.clinicaltrials.gov. Unique identifier: ISRCTN35739639.
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Effect of the Mediterranean diet on blood pressure in the PREDIMED trial: results from a randomized controlled trial.
Toledo, E, Hu, FB, Estruch, R, Buil-Cosiales, P, Corella, D, Salas-Salvadó, J, Covas, MI, Arós, F, Gómez-Gracia, E, Fiol, M, et al
BMC medicine. 2013;:207
Abstract
BACKGROUND Hypertension 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. METHODS The 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. RESULTS The 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. CONCLUSIONS Both 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 REGISTRATION Current Controlled Trials ISRCTN35739639.