Vegetarian vs Mediterranean diet for prevention of cardiovascular disease

Nutrition is able to alter the cardiovascular health of the general population. Actually, the optimal dietary strategy for cardiovascular prevention is yet far to be defined. Mediterranean and vegetarian diets are those reporting the greatest grade of evidence, but no experimental studies comparing these two dietary patterns are available. The aim of my PhD study was to implement a randomized, open, crossover clinical trial in a population of omnivorous individuals living in a low-risk European country for cardiovascular disease, in order to compare the effects of a 3-month period of vegetarian and Mediterranean diets on reducing body weight, fat mass and various cardiovascular risk parameters. We randomly assigned to overweight omnivores with a low-to-moderate cardiovascular risk profile a vegetarian diet compared to a Mediterranean diet. The outcomes were changes of body weight, body composition and risk parameters of cardiovascular disease from baseline. Anthropometric measurements and blood analyses were performed at both the beginning and end of each dietary intervention. One hundred-eighteen subjects (mean age: 51.1, females: 78%) were enrolled. The total participation rate at the end of the study was 84.7%. No significant difference between the vegetarian and Mediterranean diets was found, as both interventions produced equally effective results. In particular, a significant body weight reduction of 1.9 kg and 1.8 kg, with a significant BMI reduction of -0.6 kg/m2 and -0.7 kg/m2, and a significant fat mass reduction of 1.2 kg and 1.5 kg were reported in the vegetarian and Mediterranean diet groups, respectively. Significant differences between the two interventions were obtained for LDL-cholesterol and vitamin B12 levels, which significantly decreased by 5.44% and 5.06% only in the vegetarian diet group, and for triglyceride levels, which significantly decreased by 5.91% only in the Mediterranean diet group. Finally, there was no significant difference between dietary interventions in oxidative stress markers and inflammatory cytokines, except for interleukin-17, which improved only in the Mediterranean diet group. Overall, the vegetarian diet resulted in a reduction of 8 out of 13 cytokines with 6 that reached the statistical significance, whereas the Mediterranean diet determined a reduction of 11 out of 13 pro- and anti-inflammatory cytokines, with 7 that reached the statistical significance. Forty-six participants during the vegetarian diet period and 35 during the Mediterranean diet period reached the target values for at least one cardiovascular risk factor. In conclusion, both vegetarian and Mediterranean diets were effective in reducing body weight, BMI, and fat mass, with no significant differences between them. However, the vegetarian diet resulted more effective in reducing LDL-cholesterol levels, whereas the Mediterranean diet determined a significant reduction in triglyceride levels. These findings could be important for improving the awareness of the general population towards prevention-based interventions aimed at reducing cardiovascular disease.