Key points from article :
Socio-economic position modulates health advantages of Mediterranean diet.
Mediterranean Neurological Institute studied 18,000 people.
Better off consume healthier versions of the Mediterranean diet.
Foods are richer in antioxidants and polyphenol plant compounds.
Also had access to a greater range of fruits and vegetables.
Quality of foods may be as important as quantity and frequency.
The study was published in the International Journal of Epidemiology.
