Results of the PREDIMED study, aimed at assessing the efficacy of the Mediterranean diet in the primary prevention of cardiovascular diseases, have been published in The New England Journal of Medicine. They show that the Mediterranean diet supplemented with extra-virgin olive oil or tree nuts reduces by 30 percent the risk of suffering a cardiovascular death, a myocardial infarction or a stroke.
The study has been coordinated by the researcher Ramon Estruch, from the Faculty of Medicine of the UB and the Hospital Clínic -- affiliated centres with the health campus of the UB, HUBc -- and has had the collaboration of the professor Rosa M. Lamuela and her team from the Natural Antioxidant Research Group of the Faculty of Pharmacy -- located at the campus of international excellence BKC -- which determined the biomarkers of Mediterranean diet consumption.
The research is part of the project PREDIMED, a multicentre trial carried out between 2003 and 2011 to study the effects of the Mediterranean diet on the primary prevention of cardiovascular diseases. The study was funded by the Carlos III Health Institute by means of the cooperative research thematic network (RETIC RD06/0045) and the CIBER of Physiopathology of Obesity and Nutrition (CIBERobn).
A total of 7,447 people following major cardiovascular risk factors participated in the study. They were divided into three dietary intervention groups: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with nuts (walnuts, almonds, hazelnuts), and a low-fat diet (animal and vegetable). A dietician visited the patients every three months and they attended dietary training group sessions, in which they received detailed information about the Mediterranean and the low-fat diet, and the food included in each one. Moreover, they were provided with shopping lists, menus and recipes adapted to each type of diet and each season of the year.
During the study, those participants who followed any of the two types of Mediterranean diet received freely extra-virgin olive oil (one litre per week), and nuts (30 grams per day; 15 grams of walnuts, 7.5 grams of almonds and 7.5 grams of hazelnuts).
After five years, it has been proved that participants who followed any of the two types of Mediterranean diet showed a substantial reduction in the risk of suffering a cardiovascular death, a myocardial infarction or a stroke.
According to the researchers, the results of PREDIMED study are relevant as they prove that a high-vegetable fat diet is healthier at a cardiovascular level than a low-fat diet. The authors state that the study has been controversial as it provides new data to reject the idea that it is necessary to reduce fats in order to improve cardiovascular health.
Hopefully, these results will provide new references to prevent cardiovascular diseases. In addition, the design and methodology used can be easily transferred to the biomedical sector.
The study had the collaboration of several researchers from the Hospital Clínic, the Hospital del Mar Medical Research Institute (IMIM), the faculties of Medicine of the universities Rovira i Virgili, Navarra, Valencia, Canary Islands and Malaga, as well as the University Hospital Son Espases of Palma, the Fats Institute in Seville, and the primary health care networks of Barcelona, Seville, Tarragona and Valencia.