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Eating the Mediterranean way – just add olive oil?

While many of us associate a Mediterranean Diet with long, sun-drenched lunches indulging in fresh produce and perhaps preserved meats chased down with a glass of red wine, the origins of the diet are a lot more modest – and a lesson in history. Dietician Dr Evangeline Mantzioris explains.

You could be forgiven if you thought all you had to do to adopt a Mediterranean Diet was simply add a slosh of olive oil to your meals. While olive oil is an essential component, it turns out the benefits stem from a largely vegetarian diet originally borne out of necessity.

The Mediterranean Diet (MedDiet) is defined as the food pattern that was consumed in Crete post World War II in the 1950s. And the emphasis here is on post-World War II, as Crete (along with Greece) had suffered greatly during the war – both economically and in terms of infrastructure, including the health and education systems, which were severely impacted. This poverty that engulfed Crete is reflected in the frugality of the true Mediterranean Diet.

This dietary pattern was first noted by a US physiologist called Ancel Keys, who was on sabbatical in Italy and noticed the diet and the very low rate of heart disease. From these observations, he commenced the famous Seven Countries Study, which was set up to determine the impact of diet on chronic disease across different cohorts in the US, Japan, Finland, Italy, Netherlands, Yugoslavia and the island of Crete in Greece. The Cretan cohort had the lowest rate of heart disease and cancer despite the poorest economic situation, poorest health services, low education levels and the highest rates of smoking. The striking aspect was the level of fat in the diet was about 40 per cent of energy intake, much higher than in other countries. This study was one of the first to give us a hint that it was the type of fat, rather than the amount of fat that is important. But of course, as the Seven Countries Study was observational, we cannot directly link the favourable health outcomes to the diet. It wasn't until the 1990s that experimental studies could back up this finding. The Lyon Diet Heart study, a dietary intervention study in people who had already had a heart attack, showed that the MedDiet reduced a second subsequent heart attack. The PrediMed Study in the late 2010s showed that the MedDiet could reduce the rate of first heart attacks by about 30 per cent.

What is it?

Overall, the MedDiet is very high in plant foods, low in animal foods, and perhaps the defining aspect is that the sole source of fat in the diet is extra virgin olive oil (EVOO), so some of the current Western diet favourites – butter, coconut oil – did not feature in the diet. Typically, they would consume between 60 to 80 millilitres per day per person, and it was used in all forms of cooking, baking and cold food application in salads and for dipping bread into.

A wide array of vegetables was traditionally consumed, but importantly these included daily consumption of green leafy vegetables, often foraged in the mountainous slopes of the villages. As well as the well-known spinach, vegetables include chicory, arugula, chard, sorrel, collards and purslane. These would be eaten raw in salads or sauteed with EVOO, herbs, and lemon juice or vinegar. All up, the daily vegetable intake would be over 400 grams per day, which is more than four cups. Additionally, most vegetables were prepared in a salsa or sofrito, cooked with onion, garlic and home-preserved tomato sauce.

The meat intake was very small, and the Mediterranean dietary guide indicates that red meat should be eaten once to twice weekly. However, if you chat with Greeks who were living there at that time, they will report they were lucky to eat meat two to three times a year (Easter, Christmas and the Feast Day of the Saint of the village church). While they did have chickens, goats and sheep, these were reared to provide a continual supply of eggs and milk. The milk would be made into cheeses or yoghurt to preserve for future times and eggs were almost always reserved for children or the elderly. Fish is often represented as part of the MedDiet, but this depended on proximity to the sea or lakes.

An often-undervalued part of the diet is the minimal amount of processed foods that they consumed, and this reflects not only the little that was available commercially but also that their poverty prevented them from affording what little was available on the market. Similarly, while red wine is a feature, it is only ever consumed in small amounts and with meals.

The diet has been linked to many favourable outcomes, including improvements in heart disease, diabetes and weight control, as well as better cognitive outcomes and improved mental health. Notably, many of the health benefits occur independently of weight loss.

So what are the nutrients in the Mediterranean Diet responsible for the favourable benefits?

Firstly, the diet is very nutrient-dense, high in antioxidants, fibre and higher levels of omega-3 fats. All these lead to reduced oxidative stress and an improvement in the body's inflammatory status. The higher levels of fibre lead to a better microbiome. The diet is also very low in saturated and trans-fat and sugar, which are associated with developing and worsening chronic diseases.

Anything else?

In Greek, “diet” (Gk: διετα) means the way you choose to live your life, and a very forgotten and overlooked aspect of the MedDiet are the other key lifestyle components. These include purposeful exercise around food growing, harvesting, preparation and cooking, as well as active transportation. Most activity is outdoors, and there is growing evidence that this has better health outcomes — as does the conviviality of meals eaten and shared with family and friends. And the last essential component? Getting a good night's sleep.

Dr Evangeline Mantzioris

Dr Evangeline Mantzioris is the Program Director of Nutrition and Food Sciences at the University of South Australia. She is an Accredited Practising Dietitian and Sports Dietitian with experience in clinical dietetics, clinical teaching, and private practice. Evangeline is on the NHMRC Expert Committee for the Revision of the Australian Dietary Guidelines.

Evangeline enjoys communicating the science of nutrition to the public, speaks regularly to media and is a regular contributor to The Conversation.

Evangeline’s areas of research interests include the Mediterranean Diet through the lifespan, omega-3 fatty acids, nutrition for athletes and the nutrition–environment nexus.

Evangeline and her colleagues are currently seeking survey participants on the following topics:

The link between the Mediterranean diet and menopause

Ethics Approval Number: University Sunshine Coast: S231800; University South Australia: 205348

The link between the use of herbs and spices and the Mediterranean Diet

Ethics Approval Number: University Sunshine Coast: A221839; University South Australia: 205159

 

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