I imagine there's a lot of variability, with so many countries and cultures bordering the Mediterranean Sea, from Spain and Morocco, through France, Italy, Turkey, Israel, Egypt, and the rest of Northern Africa. Oh, and the Greek island Crete (I know Mediterranean Kiwi will say something if I don't). The benefits of the MD, if real (maybe it's the geographical location) probably depend on a combination of dietary factors, rather than any particular nutritional component.
This recent study in the British Medical Journal supports the existence of a dietary pattern, or at least it didn't refute it, "The results of our study do not refute the possibility of synergistic effects among foods and nutrients in the Mediterranean diet."
It investigated the relative importance of individual components of the MD:
Anatomy Of Health Effects Of Mediterranean Diet: Greek EPIC Prospective Cohort Study, BMJ, June 2009
- Participants were 23,349 men and women in the Greek segment of the 10-country-wide European Prospective Investigation into Cancer and nutrition (EPIC)
- Mean follow-up: 8.5 years
- Individuals were scored on "the nine widely accepted components of the Mediterranean diet:"
- High intake of vegetables
- High intake of fruits and nuts
- High intake of legumes
- High intake of fish and seafood
- High intake of cereals
- Low intake of meat and meat products
- Low intake of dairy products
- High ratio of monounsaturated to saturated lipids
- Moderate intake of ethanol
- High intake of vegetables
"Controlling for potential confounders, higher adherence to a Mediterranean diet was associated with a statistically significant reduction in total mortality."The contributions of the individual components of the MD to this association (reduced mortality) were:
- 23.5% from moderate ethanol consumption
- 16.6% from a low consumption of meat and meat products
- 16.2% from a high vegetable consumption
- 11.2% from a high fruit and nut consumption
- 10.6% from a high monounsaturated to saturated fat ratio (indicates high olive oil consumption)
- 9.7% from a high legume consumption
- High cereal consumption had minimal beneficial effect. (6.1%)
- Low dairy consumption had minimal beneficial effect. (4.5%)
- High seafood consumption had a non-significant increase in mortality. (The authors state that their Greek population had too low a seafood intake for this finding to be meaningful, and that, although the positive association was unexpected, it was "probably owing to chance.")
In as much as foods consumed in Greece may reflect the Mediterranean diet, this investigation adds to accumulating evidence that a certain dietary pattern (i.e. high in fruits and vegetables while low in meat) rather than a certain dietary component, is responsible for longevity.
The study went further though by assigning relative importance to components of that successful dietary pattern - with the top three contributors being, in order of benefit:
- Moderate alcohol intake
- Low consumption of meat
- High consumption of vegetables