In the Mediterranean basin,
olive oil, along with fruits, vegetables, and fish, is an important constituent of the diet, and is considered a major factor in preserving a healthy and relatively disease-free population. Epidemiological data show that the
Mediterranean diet has significant protective effects against
cancer and
coronary heart disease. We present evidence that it is the unique profile of the phenolic fraction, along with high intakes of
squalene and the
monounsaturated fatty acid,
oleic acid, which confer its health-promoting properties. The major phenolic compounds identified and quantified in
olive oil belong to three different classes: simple
phenols (
hydroxytyrosol,
tyrosol);
secoiridoids (
oleuropein, the aglycone of
ligstroside, and their respective decarboxylated dialdehyde derivatives); and the
lignans [(+)-1-acetoxypinoresinol and
pinoresinol]. All three classes have potent
antioxidant properties. High consumption of extra-virgin
olive oils, which are particularly rich in these phenolic
antioxidants (as well as
squalene and
oleic acid), should afford considerable protection against
cancer (colon, breast, skin),
coronary heart disease, and ageing by inhibiting oxidative stress.