A Mediterranean diet can lower the risk of a heart attack, stroke or early death for hundreds of millions of people who have an increased risk of cardiovascular disease, according to a global review of evidence.
A diet rich in olive oil, nuts, seafood, whole grains and vegetables has been linked to a number of benefits, and its effectiveness in helping healthy people live longer is well known.
There is limited evidence of how it might help those at increased risk of cardiovascular disease. These include hundreds of millions of people with obesity, type 2 diabetes, high blood pressure or high cholesterol, and those who are physically inactive, smoke or consume harmful levels of alcohol.
Guidelines recommend different diets for those with higher risk of heart problems, but they usually rely on low-certainty evidence from non-randomised studies. A large study of its kind in the world has found robust evidence in 40 randomised controlled trials involving more than 35,000 people.
A comparative review of seven programmes published in the BMJ journal shows that Mediterranean and low-fat diets reduce the risk of heart attack and death in people at heightened risk of cardiovascular disease.
The study s authors wrote that programmes promoting Mediterranean and low-fat diets with or without physical activity or other interventions reduce all-cause mortality and non-fatal myocardial infarction heart attacks in patients with increased cardiovascular risk. Mediterranean programmes are likely to reduce stroke risk. Forty trials involving 35,548 participants followed over seven diets for an average of three years were reviewed by researchers from the US, Canada, China, Spain, Colombia and Brazil.
Mediterranean diet containing low fat, very low fat, modified fat, low fat and low sodium, Ornish a vegetarian diet, low fat and refined sugar and Pritikin a plant-based diet and limiting processed food were the seven diets that were better than minimal intervention at preventing all-cause mortality, non-fatal heart attack and stroke in people at risk of cardiovascular disease.
Low-fat programmes were also superior to minimal intervention, with moderate certainty, for prevention of all-cause mortality and non-fatal heart attack.
The five other dietary programmes generally had little or no benefit compared to minimal intervention, based on low to moderate-certainty evidence.
The researchers acknowledged that there were limitations to their work, including being unable to measure adherence to diet programmes and the possibility that some of the benefits may have been due to other elements within the programmes, such as drug treatments and support to stop smoking. The BMJ said it was a comprehensive review.
It is well known that eating Mediterranean-style is good for your heart, but it is encouraging to see programmes like this lower the risk of death and heart attacks in patients already at risk of cardiovascular disease, said Tracy Parker, senior dietitian at the British Heart Foundation.
She said that if you are at risk or not, a balanced diet like the Mediterranean-style diet can help you to reduce your risk of developing heart and circulatory diseases. The risk factors associated with cardiovascular disease such as type 2 diabetes, obesity, high blood pressure and high cholesterol are also reduced with a Mediterranean diet.
It is easy to eat lots of fruit and vegetables, beans, lentils, whole grains, fish, nuts and seeds, along with some low-fat dairy and fat from unsaturated sources like olive oil. It is important to eat less processed meat, salt and sweet treats.