Health providers in continental diet-based countries suggest to embracing Mediterranean diet in order to contribute in reducing cardiovascular mortality. However, countries in the Mediterranean area are experiencing a shift in dietary habit towards continental diet with potential harmful change in mortality rates. Oxidative stress, including free radical-driven reactions and antioxidant status are considered important mediators to be considered in the diet-mediated effect on health. Important metabolic functions are also mediated by certain fatty acids. A comprehensive study of oxidative stress, including free radical-driven products and protective antioxidants, and fatty acids metabolism has never been reported in healthy subjects. In particular, high sensitive mass-spectrometry methods to study oxidative stress and fatty acids metabolism are rarely applied to epidemiological studies.