OPINION: If you’ve ever have the misfortune of a heart attack or are considered at risk of heart disease or stroke, your doctor will probably prescribe a statin drug, such as atorvastatin (Lipitor), to lower your blood cholesterol levels.
Recent reports of an Italian study have suggested adhering to a Mediterranean-style diet may actually better protect people from a heart attack or stroke than taking a statin.
Such a claim can’t really be made. To do so, we’d need a trial in which a large number of well-matched participants were randomly given either statins or a Mediterranean-style diet, and followed faithfully to see the comparative results.
Such a trial is unlikely to occur, as withholding medication from people at risk of heart attack or stroke would be regarded as unethical.
But I also suspect ethics committees would be unlikely to recommend anyone avoid following the healthy features of a Mediterranean-style diet, which so many studies have shown to be protective.
The Italian study and statins
The recent Italian study randomly enrolled more than 25,000 people, about 1,200 of whom reported a prior history of heart attack, stroke or blocked arteries at enrolment. Each person recorded their usual diet over the next seven years. Researchers recorded deaths from any cause.
Participants' diets were given a score out of nine, based on how many features of a healthy Mediterranean-style diet they followed. Those with higher scores had a 37% lower risk of premature death compared with those with lower scores.
These results were controlled for confounding factors, including age, sex, smoking, exercise, energy intake, waist-to-hip ratio, blood pressure, blood cholesterol levels and diabetes.
The benefits of statins on various levels of heart health have also been extensively researched. A recent randomised controlled trial compared statins with a placebo in 21 countries in 12,705 people who were at higher-than-average risk of heart disease.
Over the more than five years of this study, those on statins had a 23% reduction in heart attack, stroke or heart-related death compared with those on placebo. There were no differences in diabetes or cancers, but those on statins were 20% more likely to have muscle symptoms, such as weakness or pain, and 18% more likely to have cataract surgery.
The Mediterranean-style diet
There is no one Mediterranean diet, nor does every Mediterranean country have a diet that ticks every healthy box. However, dozens of studies have defined the features of what makes a Mediterranean dietary pattern healthy.
Primarily, the diet needs to be based on whole or minimally processed foods. Positive points accrue for protective foods such as fruits, vegetables, legumes, nuts, wholegrains, fish, olive oil and modest amounts of alcohol consumed with meals. High intakes of red and processed meats, sugary foods and drinks, refined grain products and fast foods all score negative points.
The benefits of certain Mediterranean diets were first publicised in the 1960s. Researchers found that rates of death from heart disease were three times higher in Northern European countries (top score to Finland) compared with four groups studied in Southern Europe.
During the 1990s, the Lyon Heart Study began. This was a long-term study designed for participants who had already had a heart attack. It produced results so favourable for the benefits of Mediterranean eating patterns compared with the standard diet advice usually given that it was stopped early. Results four years later confirmed the original benefits of the Mediterranean eating pattern.
Even more dramatic results were claimed from the HALE study in Europe. Conducted between 1988 and 2000, the trial involved 2,340 older men and women in 11 European countries.
Those who followed a Mediterranean-style diet and a generally healthy lifestyle – no smoking, moderate alcohol intake and regular physical activity – had more than a 50% lower rate of death from any cause.
A more recent trial in Spain of people who had not had a heart attack but were considered at high risk has confirmed the value of a Mediterranean eating pattern.
One-third of its 7,500 participants were asked to follow a Mediterranean eating pattern and add extra olive oil; another third followed the same basic diet but were given extra tree nuts. The remaining third were asked to follow a low-fat diet, although this section of the study failed as the participants barely changed their fat intake.
The study found adding extra olive oil or nuts to the basic Mediterranean eating style conferred many benefits for heart health. This study also showed that the higher the intake of saturated fat in each group, the worse the results.
Whether the Mediterranean diet can outdo statins may be up for debate. However, there’s no doubting the strong evidence for a Mediterranean eating pattern for everyone. Even for those on statins, a healthy Mediterranean eating pattern has been shown to bring extra benefits.
Rosemary Stanton is a Nutritionist & Visiting Fellow, UNSW.
This opinion piece was first published on The Conversation.