Mediterranean Diet and all-cause mortality

Antonia Trichopoulou is one of the authors of the landmark study that put Mediterranean Diet on the dietary map. It was her initial description of the Mediterranean Diet's 9 points that has led to the research we have today into this pattern of eating.

Today we have a meta-analysis (a study incorporating data from other studies) published late last year from a team including Dr. Trichopoulou that draws on the research in 30 prospective studies (that is, studies that follow people over time) from across the globe that looked at the association between Mediterranean Diet scores and overall mortality (Brit Nutr J 2018;120:1081-1097). These 16 studies included a total of over 1.6 million people, and those studies lasted from about 7 years to over 40 years in duration.

The team drew dietary data from these original 30 studies to assess the Mediterranean Diet scores used by the original researchers (mostly 0-8 points or 0-9 points), and where possible used the score most closely matching the Mediterranean Diet score described in the diet's originating research by Dr. Trichopoulou.

The authors compared the Mediterranean Diet scores of those 250,000+ participants who died over the course of their respective studies with those who did not, and found that compared to those with the lowest Mediterranean Diet score (either 0-2 or 0-3), those with the highest overall Mediterranean Diet scores (either 6-8 or 6-9), were 21% less likely to die of any cause.

They didn't stop there, but continued their analysis to tease out which of the nine points of the Mediterranean Diet contributed most strongly to that reduction in mortality. Those components showing a clinically significant reduction in mortality were greater-than-average-amounts of fruits/nuts and vegetables, and a moderate intake of alcohol (as opposed to either no alcohol or an excessive amount). Indeed, as opposed to those with no intake of alcohol or an excessive intake, those with a moderate (1-2 drink per day, on average) intake were 14% less likely to die.

Similarly, higher intake of meats (that is, protein from land animals as opposed to fish or shellfish) was associated with a higher risk of all-cause mortality, while dairy products also showed what the authors termed a "weak" positive association with mortality - meaning more dairy equals higher risk of death. (Contrast this to a recent column on "Using Mediterranean Diet to promote dairy".)

The authors also analyzed the relative risk of death for the various levels of Mediterranean Diet adherence, and found that a 2-point increase in a Mediterranean Diet score, which they term a "realistic increment of adherence" (read that: "realistically attainable for most people"), would yield at least an 8% reduction in all-cause mortality. This is not the 25% reduction I have been citing up until now, but it's still a real and significant difference - and it's all-cause mortality, which by definition includes everything from congestive heart failure to heart attack to stroke to pneumonia.

What this means for you

If you are going to choose two or three points of the Mediterranean Diet to focus on to improve your diet in 2019, the research says it should be these three: more fruits and nuts, more vegetables, less land animal protein, and less dairy. That doesn't mean NO land animal protein: just limit your intake to leaner meats no more than once per week. For the same reason, you should limit your dairy intake to cheeses and fermented dairy like yogurt or sour cream.

First posted: January 9, 2018