According to a substudy of PREDIMED published in the Annals of Internal Medicine:"Compared with a low-fat diet, Mediterranean diets supplemented with olive oil or nuts have beneficial effects on cardiovascular risk factors."
How was the study done?
772 asymptomatic people aged 55 to 80 years were recruited for the study. Participants were assigned to a low-fat diet or to one of 2 types of a Mediterranean diet. Those allocated to Mediterranean diets received either free virgin olive oil (1 liter per week), or free nuts (30 gm/day). The authors evaluated laboratory outcomes at 3 months.
Mediterranean diet improved (decreased) plasma glucose levels, systolic blood pressure, cholesterol, and C-reactive protein levels compared to the low-fat diet. The changes were small and the study was not powered to show any clinical significance, but again, the intervention duration was only 3 months
Further Reading from Wikipedia
Cuisine of the Mediterranean
Mediterranean diet
References:
Effects of a Mediterranean-Style Diet on Cardiovascular Risk Factors.
Ramon Estruch et al., Annals of Internal Medicine, 7/2006.
Why to Eat Like a Greek http://goo.gl/Chpwf - Mediterranean diet improves heart risk factors http://goo.gl/DkPhF
Image source: Olive oil, Wikipedia
Image source: Olive oil, Wikipedia