Research article
Effect of the Mediterranean diet on blood pressure in the PREDIMED trial: results from a randomized controlled trial
1 Department of Preventive Medicine and Public Health, University of Navarra, Pamplona, Navarra, Spain
2 Department of Nutrition, Harvard School of Public Health, Boston, MA, USA
3 CIBER Fisiopatología de la Obesidad y Nutrición (CIBER OBN), Instituto de Salud Carlos III (ISCIII), Spanish Government, Madrid, Spain
4 Harvard Medical School and Channing Lab, Brigham Women’s Hospital, Boston, MA, USA
5 Department of Internal Medicine, Institut d’Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Hospital Clinic, University of Barcelona, Barcelona, Spain
6 Department of Preventive Medicine and Public Health, University of Valencia, Valencia, Spain
7 Human Nutrition Department, IISPV, Universitat Rovira i Virgili, Reus, Spain
8 Cardiovascular and Nutrition Research Group, Institut de Recerca Hospital del Mar, Barcelona, Spain
9 Department of Cardiology, University Hospital of Alava, Vitoria, Spain
10 Department of Preventive Medicine, University of Malaga, Malaga, Spain
11 Institute of Health Sciences IUNICS, University of the Balearic Islands, and Hospital Son Espases, Palma de Mallorca, Spain
12 Department of Family Medicine, Primary Care Division of Sevilla, San Pablo Health Center, Sevilla, Spain
13 Department of Clinical Sciences, University of Las Palmas de Gran Canaria, Las Palmas, Spain
14 Lipids and Vascular Risk Unit, Internal Medicine, Hospital Universitario de Bellvitge, Hospitalet de Llobregat, Barcelona, Spain
15 Department of Nutrition and Food Science, School of Pharmacy, XaRTA, INSA, University of Barcelona, Barcelona, Spain
16 Department of Biochemistry and Molecular Biology, School of Medicine, University of Valencia, Valencia, Spain
17 Department of Clinical Analyses, University Hospital of Valencia, Valencia, Spain
18 Instituto de la Grasa, Consejo Superior de Investigaciones Cientificas, Sevilla, Spain
19 Lipid Clinic, Department of Endocrinology and Nutrition, Institut d’Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Hospital Clinic, University of Barcelona, Barcelona, Spain
20 Primary Care Division, Valencia Institute of Health, Valencia, Spain
BMC Medicine 2013, 11:207 doi:10.1186/1741-7015-11-207
Published: 19 September 2013Abstract
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
