It is simply a well-known fact, the best olive oil comes from the Southern Italian Apulian region!
I remember growing up, a car (as in motorcar) oil company, Castrol ran a TV campaign called "Oils ain't oils." (see the ad here: https://www.youtube.com/watch?v=c7TUiMCeils).
Nearly 40 years on, that saying could not be more appropriate!
Today health research is very clear, our body needs good, clean oils, high in Omega's, Oleic Acid, Phytosterols, and Vitamin E. These together provide significant benefits to the human body; both anti-inflammatory and cardio-protective.
In short, good olive oil is a nutritional powerhouse.
The problem is, oils ain't oils - not all olive oils are made equally; today's consumer products offer cheap substitutions offering little more than GMO canola oil with some herbs.
EVOO (Extra Virgin Olive Oil), or as we say in Italian "olio extra vergine di oliva" is not a cheap product, the process from seed to fruit to extraction and bottling provides for stringent process and quality assurances to ensure the purest olive oils available.
So for the connoisseur who wants a premium, as advertised EVOO, with all the health benefits, forget your supplements, and think more "Mediterranean" diet. Make the switch, your taste buds and body will thank you.