Mediterranean diet, based on fruits, vegetables, virgin olive oil and tree nuts, rich in antioxidants and monounsaturated fatty acids, has long been believed to be beneficial for cardiovascular health. Oddly enough though, until now, there have been no proper scientific studies done to test these assumptions.

With oxidative damage being blamed for heart disease, cancer, neurodegenerative diseases and also aging it has simply been assumed that a diet rich in phenolic compounds with strong antioxidant and anti-inflammatory properties and other bioactive compounds, such as fibre, phytosterols and folic acid would be beneficial for one’s cardiovascular health.

Now, for the first time, a research group, lead by Dr Maria Isabel Covas (Spain), has taken on the challenge to scientifically investigate the antioxidant effects of the Mediterranean diet on in vivo (meaning on a live organism) lipoprotein oxidation and consequently its efficacy on the prevention of cardiovascular diseases in a long-term, multicenter, randomized, controlled clinical trial.

The PREDIMED study includes 9000 high-risk participants divided into 3 groups: Mediterranean diet with virgin olive oil, Mediterranean diet with mixed nuts and a low-fat diet group. The researchers are interested in cardiovascular events such as cardiovascular death, nonfatal myocardial infarction and nonfatal stroke. The study started at the beginning of 2007 with final results expected by late 2010.

The first preliminary results after only 3 months are already showing some positive effects of the Mediterranean diet. The weight and body mass index (BMI) were both slightly reduced in all 3 groups with no significant differences between them. The really exciting bit though is that all participants also had lower mean plasma glucose level, lower systolic blood pressure, lower total-cholesterol/HDL-cholesterol ratios and lower oxidized LDL levels, with significant differences between participants in the two Mediterranean diet groups versus those in the low-fat diet group. The two Mediterranean diet groups showed significantly bigger improvements in those parameters than the low-fat diet group. Mediterranean diet supplemented with virgin olive oil was the better of the two Mediterranean diets, the difference however was not statistically significant.

After only 3 months the preliminary results are clearly showing beneficial effects of Mediterranean diet, especially when supplemented with virgin olive oil, on many cardiovascular disease risk factors such as high blood pressure and high blood glucose and cholesterol levels. Whether or not this translates to real reduction in cardiovascular morbidity and mortality remains to be seen however. Hopefully the long-term results of this study will be able to answer this question.

In the meantime why not treat yourself to some extra virgin olive oil in your salads and add some fish to your lunch or dinner plate.