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


BACKGROUND
Current Controlled Trials ISRCTN35739639.
Department of Preventive Medicine and Public Health, University of Navarra, Pamplona, Navarra, Spain. mamartinez@unav.es.
Estefania
E
Toledo
Frank B
FB
Hu
Ramon
R
Estruch
Pilar
P
Buil-Cosiales
Dolores
D
Corella
Jordi
J
Salas-Salvadó
M Isabel
MI
Covas
Fernando
F
Arós
Enrique
E
Gómez-Gracia
Miquel
M
Fiol
Jose
J
Lapetra
Luis
L
Serra-Majem
Xavier
X
Pinto
Rosa M
RM
Lamuela-Raventós
Guillermo
G
Saez
Mònica
M
Bulló
Valentina
V
Ruiz-Gutiérrez
Emilio
E
Ros
José V
JV
Sorli
Miguel Angel
MA
Martinez-Gonzalez
D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D016022:Case-Control Studies; D038441:Diet, Mediterranean; D005260:Female; D006801:Humans; D006973:Hypertension / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009754:Nuts; D000069463:Olive Oil; D010938:Plant Oils; D011322:Primary Prevention / Q000379:methods*; D016037:Single-Blind Method
D000069463:Olive Oil; D010938:Plant Oils