Reduction in the Incidence of Type 2 Diabetes With the Mediterranean Diet

Results of the PREDIMED-Reus nutrition intervention randomized trial

  1. for the PREDIMED Study Investigators
  1. 1Human Nutrition Unit, Hospital Universitari de Sant Joan, Departament de Bioquímica i Biotecnologia, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus, Spain;
  2. 2CIBER Fisiopatologia de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain;
  3. 3Department of Preventive Medicine and Public Health, University of Navarra, Pamplona, Spain;
  4. 4SAP Reus-Altebrat, Institut Català de la Salut, Reus, Spain;
  5. 5Department of Internal Medicine, Institut d'Investigacions Biomèdiques August Pi Sunyer, Hospital Clínic, Barcelona, Spain;
  6. 6Cardiovascular Risk and Nutrition Research Group, Institut Municipal d'Investigació Mèdica, Barcelona, Spain;
  7. 7Department of Preventive Medicine and Public Health, University of Valencia, Valencia, Spain;
  8. 8Department of Cardiology, University Hospital Txagorritxu, Vitoria, Spain;
  9. 9Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, Seville, Spain;
  10. 10Lipid Clinic, Service of Endocrinology and Nutrition, Institut d'Investigacions Biomèdiques August Pi Sunyer, Hospital Clínic, Barcelona, Spain.
  1. Corresponding author: Jordi Salas-Salvadó, jordi.salas{at}


OBJECTIVE To test the effects of two Mediterranean diet (MedDiet) interventions versus a low-fat diet on incidence of diabetes.

RESEARCH DESIGN AND METHODS This was a three-arm randomized trial in 418 nondiabetic subjects aged 55–80 years recruited in one center (PREDIMED-Reus, northeastern Spain) of the Prevención con Dieta Mediterránea [PREDIMED] study, a large nutrition intervention trial for primary cardiovascular prevention in individuals at high cardiovascular risk. Participants were randomly assigned to education on a low-fat diet (control group) or to one of two MedDiets, supplemented with either free virgin olive oil (1 liter/week) or nuts (30 g/day). Diets were ad libitum, and no advice on physical activity was given. The main outcome was diabetes incidence diagnosed by the 2009 American Diabetes Association criteria.

RESULTS After a median follow-up of 4.0 years, diabetes incidence was 10.1% (95% CI 5.1–15.1), 11.0% (5.9–16.1), and 17.9% (11.4–24.4) in the MedDiet with olive oil group, the MedDiet with nuts group, and the control group, respectively. Multivariable adjusted hazard ratios of diabetes were 0.49 (0.25–0.97) and 0.48 (0.24–0.96) in the MedDiet supplemented with olive oil and nuts groups, respectively, compared with the control group. When the two MedDiet groups were pooled and compared with the control group, diabetes incidence was reduced by 52% (27–86). In all study arms, increased adherence to the MedDiet was inversely associated with diabetes incidence. Diabetes risk reduction occurred in the absence of significant changes in body weight or physical activity.

CONCLUSIONS MedDiets without calorie restriction seem to be effective in the prevention of diabetes in subjects at high cardiovascular risk.


  • Clinical trial reg. no. ISRCTN35739639,

  • The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

  • Received July 6, 2010.
  • Accepted September 28, 2010.

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  1. Diabetes Care vol. 34 no. 1 14-19
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