Feature: Researchers explore the effects of a Mediterranean diet on cardiovascular health

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Can eating more plant-based foods, less saturated fats and more whole grains lower our risk for heart disease?

A systematic review of 30 randomized control trials found that while there is still some uncertainty about whether this type of diet can prevent heart attack and stroke in those with already established heart disease, there is evidence to support its effectiveness in reducing risk factors like blood lipid levels and blood pressure in healthy individuals.

The review published today in the high-profile journal Cochrane Review was led by Dr. Saverio Stranges, Professor and Chair at Schulich Medicine & Dentistry in collaboration with Manchester University and Warwick University in the UK. The review looked specifically at the effects of a Mediterranean-style diet on cardiovascular health.

“This review shows that the scientific evidence is promising and generally supportive of favourable effects of the Mediterranean-style diet on individual cardio-metabolic risk factors,” said Dr. Stranges, lead author on the review. “That evidence is corroborated by the biological plausibility of several mechanisms to explain the beneficial effect of the diet, as a whole, and of its individual components on cardiovascular health.”

Interest in studying the effects of the Mediterranean diet began in the 1960s after observations that the populations in countries such as Greece and Italy had lower mortality from cardiovascular disease compared with other populations.

A Mediterranean-style diet is defined as having a high consumption of monounstauratuated fats like olive oil and tree nuts, compared to saturated fats, and a high intake of plant based foods, including fruits vegetables and legumes. Additional components include high consumption of whole grains and low consumption of meat.

Some aspects and components of a this diet are already included in scientific and clinical guidelines to promote healthy eating, such as the Eatwell Guide published by Public Health England in 2018 and the new Canada Food Guide.

The review shows that evidence is still uncertain when it comes to demonstrating whether this kind of dietary intervention can prevent heart attack or stroke in individuals with already established heart disease, but the researchers hope that the results of seven ongoing trials will help to reduce this uncertainty.

“While some of the evidence on secondary prevention is uncertain, it is clear that nutrition management should be part of the portfolio for primary care practitioners to help prevent chronic disease,” said Dr. Stranges.

Read Cochrane Library's Q&A with Dr. Stranges