What Is a Mediterranean Diet and What Are the Benefits?

Mediterranean Diet Foods

What is the Mediterranean Diet?

The Mediterranean diet is a way of eating based on traditional foods and drinks of the countries surrounding the Mediterranean Sea. The archetypal traditional ‘Cretan’ Mediterranean diet was first established three decades ago as a cardio-protective diet in the Seven Countries Study. Keys and co-workers found that residents in Crete in Greece had the lowest mortality from heart disease and this was positively associated with their dietary pattern.

This traditional dietary pattern is characterized by an abundance of plant-based foods such as leafy green vegetables, tomatoes, onions, garlic, herbs, whole grain cereals, nuts and seeds, olive oil used as the main added dietary fat, moderate amounts of low-fat dairy products, fish and seafood, smaller quantities of red meat and red wine to be consumed in moderation with meals.

Meditterenian Diet Pyramid including recommended portions
Figure 1. The Mediterranean diet food pyramid. Recommended portions for the various food groups are illustrated.

Benefits of a Mediterranean Diet

There is an array of benefits associated with consuming this dietary pattern such as reduction or maintenance of weight, primary and secondary prevention of cardiovascular disease (CVD), and it has more recently been linked to reducing non-alcoholic fatty liver disease (NAFLD).

Since the establishment of the Mediterranean diet over three decades ago, there has been increasing scientific evidence regarding the consumption of this dietary pattern. Keys and co-workers proposed that the high consumption of monounsaturated fats due to increased intake of extra virgin olive oil, and low intakes of saturated fats contributed to the low morality rate seen within this population group.

Wider research has since established the cardio-protective nature of the Mediterranean diet stems from the high consumption of bioactive compounds such as polyphenols in red wine and plant-based foods and extra-virgin olive oil, which is also believed to have an anti-inflammatory effect. The cardioprotective nature of this dietary pattern has been exemplified in two landmark studies: The Lyon Diet Heart Study and Prevención con Dieta Mediterránea (PREDIMED) intervention trial.

PREDIMED is a Spanish primary prevention randomised control trial (n=7447) in high-risk middle-aged people in Spain. The study had three intervention groups: 1) a Mediterranean diet enriched with extra virgin olive oil; 2) a Mediterranean diet enriched with mixed nuts and 3) a control low-fat diet. In 2013, the final report of the PREDIMED trial indicated a 30% absolute risk reduction in the incidence of a first major cardiovascular event.

The Lyon Diet Heart Study is a randomised secondary prevention trial (n=605), which evaluated whether a Mediterranean type diet could reduce the rate of secondary cardiovascular events. The study was published in 1999 and reported a 70% reduction in adverse cardiovascular events after initial MI compared to a control low-fat diet. The findings of this study were so significant; the ethics committee could no longer justify keeping individuals in the control-arm and ceased the study.

These two landmark studies exemplify the cardio-protective nature of this dietary pattern. However, there is a range of other benefits associated with this dietary pattern such as:
• Reduction in NAFLD
• Modest weight-loss
• Reduction of abdominal adiposity or central obesity
• Evidence for a decline in depression and anxiety disorders
• Slowed cognitive decline and decreased risk of dementia
• Declines in Type II Diabetes Mellitus
• Declines in Cancer

However, most of this present research has been done in a Mediterranean population, which limits its generalisability. Although more and more research in non-Mediterranean populations is under wraps, so you need to watch this space – there are big things coming for this dietary pattern in a non-Mediterranean population group. While it is too early to call whether changes to Australian dietary guidelines should incorporate more Mediterranean-style foods, if the benefits of this dietary pattern are replicated in a non-Mediterranean population group, then this could be a very real reality in the future.

As such, the Mediterranean diet has become one of the highest regarded dietary patterns to date. Not only is the consumption of this dietary pattern associated with a range of health benefits, it is also known for its palatability and cost-effectiveness, the Mediterranean diet is the gift that keeps on giving.

Pass the olive oil, please?

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