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A Large Randomized Individual and Group Intervention Conducted by Registered Dietitians Increased Adherence to Mediterranean-Type Diets: The PREDIMED Study

https://doi.org/10.1016/j.jada.2008.04.011Get rights and content

Abstract

Objective

To assess the effectiveness of an intervention aimed to increase adherence to a Mediterranean diet.

Design

A 12-month assessment of a randomized primary prevention trial.

Subjects/settings

One thousand five hundred fifty-one asymptomatic persons aged 55 to 80 years, with diabetes or ≥3 cardiovascular risk factors.

Intervention

Participants were randomly assigned to a control group or two Mediterranean diet groups. Those allocated to the two Mediterranean diet groups received individual motivational interviews every 3 months to negotiate nutrition goals, and group educational sessions on a quarterly basis. One Mediterranean diet group received free virgin olive oil (1 L/week), the other received free mixed nuts (30 g/day). Participants in the control group received verbal instructions and a leaflet recommending the National Cholesterol Education Program Adult Treatment Panel III dietary guidelines.

Main outcome measures

Changes in food and nutrient intake after 12 months.

Statistical analyses

Paired t tests (for within-group changes) and analysis of variance (for between-group changes) were conducted.

Results

Participants allocated to both Mediterranean diets increased their intake of virgin olive oil, nuts, vegetables, legumes, and fruits (P<0.05 for all within- and between-group differences). Participants in all three groups decreased their intake of meat and pastries, cakes, and sweets (P<0.05 for all). Fiber, monounsaturated fatty acid, and polyunsaturated fatty acid intake increased in the Mediterranean diet groups (P<0.005 for all). Favorable, although nonsignificant, changes in intake of other nutrients occurred only in the Mediterranean diet groups.

Conclusions

A 12-month behavioral intervention promoting the Mediterranean diet can favorably modify an individual's overall food pattern. The individual motivational interventions together with the group sessions and the free provision of high-fat and palatable key foods customary to the Mediterranean diet were effective in improving the dietary habits of participants in this trial.

Section snippets

Overview of the PREDIMED Study

The PREDIMED study is a multicenter, randomized, controlled, single-blinded 4-year clinical trial that aims to assess the effects of a Mediterranean-type diet on the risk of major cardiovascular events. Two individual motivational interviews every 3 months to negotiate nutrition goals, and group educational sessions on a quarterly basis, focused to adapt the customary diet to a traditional Mediterranean diet, were compared with a control group, which received verbal instructions and a leaflet

Results

The initial sample consisted initially of 1,766 participants (643, 558, and 565 in the Mediterranean diet plus olive oil, Mediterranean diet plus mixed nuts, and control group, respectively). Their mean age was 67.4 years (53.4% were women). The number of contacted and eligible subjects was 2,507 and 2,065, respectively. Among 299 noneligible subjects, 148 did not meet inclusion criteria, 63 declined to participate, 38 could not change their diet, 35 had chronic alcoholism, nine had

Discussion

In this multicenter, randomized, primary prevention trial of cardiovascular disease, a behavioral intervention aimed to improve a Mediterranean-style diet enhanced by provision of palatable, healthful fat-rich foods (virgin olive oil or mixed nuts) was useful in achieving significant changes in the consumption of key food items, and participants who were assigned to Mediterranean diet groups showed a greater adherence to this food pattern. Our results show that the free provision of these

Conclusions

Dietary changes after 12 months in the PREDIMED study indicate that individual motivational interventions together with group sessions and the free provision of high-fat and palatable key foods customary in a Mediterranean diet were effective in improving the dietary habits of participants in this trial, who already followed a Mediterranean-type diet in part. Dietary changes achieved after an intervention for 12 months were similar to those observed at 3 months, which led to substantial

I. Zazpe is a research fellow, Department of Preventive Medicine and Public Health and Department of Nutrition and Food Sciences, Physiology, and Toxicology, University of Navarra, Pamplona, Spain.

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    I. Zazpe is a research fellow, Department of Preventive Medicine and Public Health and Department of Nutrition and Food Sciences, Physiology, and Toxicology, University of Navarra, Pamplona, Spain.

    A. Sanchez-Tainta is a research fellow and M. A. Martinez-Gonzalez is professor & chair of Epidemiology, both with the Department of Preventive Medicine and Public Health, School of Medicine–Clinica Universitaria de Navarra, University of Navarra, Pamplona, Spain.

    R. M. Lamuela-Raventos is associate professor of food sciences, Department of Nutrition and Food Science, University of Barcelona, Barcelona, Spain.

    H. Schröder is a senior research scientist, Lipids and Cardiovascular Epidemiology Research Unit, Institut Municipal d'Investigació Mèdica, Hospital de Mar, Parc de Recerca Biomèdica de Barcelona, and CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Madrid, Spain.

    R. Estruch is associate professor of internal medicine, Department of Internal Medicine, Hospital Clinic, University of Barcelona, and CIBEROBN, ISCIII, Madrid, Spain.

    J. Salas-Salvado is professor of nutrition, Human Nutrition Department, School of Medicine, University Rovira i Virgili, San Llorenc, Spain.

    D. Corella is associate professor of epidemiology, Department of Preventive Medicine, School of Medicine, University of Valencia, Valencia, Spain, and CIBEROBN, ISCIII, Madrid, Spain.

    M. Fiol is attending physician of cardiology, Institut Universitàri de Ciències de la Salut, Universidad de les Illes Balears, Palma de Mallorca, Spain, and CIBEROBN, ISCIII, Madrid, Spain.

    E. Gomez-Gracia is associate professor of epidemiology, Department of Epidemiology, School of Medicine, University of Malaga, Malaga, Spain.

    F. Aros is attending physician of cardiology, Department of Cardiology, Hospital Txangorritxu, Alava, Spain.

    E. Ros is associate professor of internal medicine, Unitat de Lípids, Servei d'Endocrinologia i Nutrició, Institut d'Investigacions Biomediques August Pi i Sunyer, Hospital Clínic, Barcelona, Spain, and CIBEROBN, ISCIII, Madrid, Spain.

    V. Ruíz-Gutierrez is professor of biochemistry, Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, Sevilla, Spain.

    P. Iglesias is attending physician of community medicine, Department of Family Medicine, Primary Care Division of Sevilla, Sevilla, Spain, and CIBEROBN, ISCIII, Madrid, Spain.

    M. Conde-Herrera is associate professor of epidemiology, Department of Epidemiology and Public Health, Hospital Virgen del Rocío, Sevilla, Spain.

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