Health In Focus
  • Mediterranean diet to which nuts or extra-virgin olive oil is added reduces the risk of serious heart diseases such as stroke and heart attack in persons who are considered high risk for developing heart disease
  • According to the World Health Organization (WHO), each year close to 18 million people die of heart disease across the world, accounting for more than 30 percent of global deaths
  • The risk factors for developing heart disease include smoking, unhealthy dietary habits, lack of physical activity along with poorly controlled blood pressure, blood sugar, high levels of low-density lipoprotein (LDL) cholesterol or bad cholesterol and being overweight

Consuming a Mediterranean diet supplemented with extra-virgin oil or nuts can reduce the risk of developing heart disease in high-risk patients, according to a recent report published in the reputed journal New England Journal of Medicine (NEJM).

Details of Study

  • The study was conducted across several centers in Spain. Over 7000 participants between the ages of 55 to 80 years (57% female) participated in the study, which began in 2009
  • All the participants were healthy at the time of enrollment. However, they had risk factors for developing heart disease such as
    • Type 2 diabetes mellitus or any three of the following major risk factors namely
    • High blood pressure
    • Smoking history
    • Being overweight or obese
    • Elevated low-density lipoprotein cholesterol levels
    • Low high-density lipoprotein cholesterol levels, or a
    • Family history of an early onset coronary artery disease
  • Participants were assigned to one of three diet groups namely -
    • A Mediterranean diet group along with extra-virgin olive oil daily (study group)
    • A Mediterranean diet along with mixed nuts (walnuts, hazelnuts and almonds) (study group), or
    • A control group diet where the members were instructed to follow a low-fat diet
  • After 4.8 years the participants were followed up for occurrence of serious heart diseases such as heart attack and stroke

Findings of the Study

  • A total of 288 cases of serious heart disease was reported among the participants in all the three diet groups
  • Of the 288 cases of serious heart disease, there were
    • 96 cases (3.8%) in the Mediterranean diet group supplemented with extra-virgin oil
    • 83 cases (3.4%) in the Mediterranean diet group supplemented with mixed nuts and
    • 109 (4.4%) cases in the control group who followed a low fat diet
  • The results were first published in 2013 in the NEJM but due to the identification of certain departures from the protocol of conducting a randomized controlled trial (a clinical study where participants are randomly assigned to either study or control groups to compare the effects of a specific treatment or intervention), this report was withdrawn
  • Following reanalysis of data after excluding the 1588 participants whose assignment to the Mediterranean diet study group was suspected to have departed from trial protocol the report was once again republished in 2018
  • The results of the reanalysis revealed similar results as shown in the 2013 report
Thus the study suggests that the incidence of serious heart diseases such as heart attack and stroke was lower among high-risk individuals who were assigned to a Mediterranean diet along with either extra-virgin olive oil or nuts than among those assigned to a low-fat diet.
Mediterranean Diet Supplemented With Nuts or Extra-virgin Olive Oil Delays Onset of Heart Disease

Results of Previous Studies on Mediterranean Diet

In earlier population based studiesas well as the Lyon Diet Heart Study which assessed the benefits of a Mediterranean diet in reducing the risk of a second occurrence of heart disease in persons who already had an initial episode of heart disease (secondary prevention), it has been shown that consuming a Mediterranean diet has been consistently associated with lower heart disease risk.

The Mediterranean diet has been rated by a systematic review as the most probable dietary model to offer protection against heart disease.

Inspired by the findings of these earlier studies the authors of the current study designed their trial to assess the role of the Mediterranean diet in reducing the risk of onset of heart disease in healthy persons (primary prevention).

What is the Mediterranean Diet?

The Mediterranean diet consists of consuming a high proportion of olive oil, unrefined cereals, legumes and plenty of fruits, and vegetables, moderate to high amounts of fish, low quantities of dairy products, processed meats, sweets and red meat; and wine in moderation, consumed with meals and low quantities of non-fish meat products.

The Mediterranean diet is based primarily on the eating habits of Southern Italy, Greece and Spain during the 1940s and 1950s.

There is evidence in the published literature that adhering to a Mediterranean diet has a beneficial effect in preventing heart disease, believed mainly to be due to the beneficial effects of olive oil

References :
  1. Cardiovascular disease - (
  2. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts - (

Source: Medindia

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