Doctors say the Mediterranean diet isn't the silver bullet for solving heart disease problems for people with high cholesterol.

The Mediterranean diet will help reduce the risk of heart disease but it isn't enough to prevent some people with high cholesterol from dying from a heart attack, doctors warn.

The warning was sparked by claims at a global medical conference that heart disease is better treated with a Mediterranean-style diet than cholesterol-lowering drugs, known as statins.

A study found that those who ate mainly along Mediterranean lines - with lots of nuts, fish, oils and vegetables - were 37 per cent less likely to die than those who were furthest from this dietary pattern.

"So far research has focused on the general population, which is mainly composed of healthy people," leading heart disease expert Professor Giovanni de Gaetano told the conference in Rome.

"What happens to people who have already suffered from cardiovascular disease? Is the Mediterranean diet optimal for them too?"

The study followed 1200 people with a history of heart attacks, strokes and blocked arteries over seven years. During that time, 208 patients died but the closer people followed an ideal Mediterranean diet the less likely they were to be among the fatalities.

But the Heart Foundation's chief medical advisor Garry Jennings, who is in Italy for the conference, has urged caution.

A healthy diet as part of a healthy lifestyle and statins should be combined, he suggested.

"The evidence for statin use in everyone who has had a heart attack who can tolerate them is unequivocal and comes from large scale randomised trials, which is a higher level of evidence than this observational study," he said in a statement on Monday.

It's not the first time the use of statins has been called into question, with more than 60,000 Australians having cut back on or stopped taking statins after ABC TV's Catalyst program questioned their effectiveness in 2013.

The Australian Medical Association warns people against ripping up their prescriptions.

Dr Richard Kidd, a Brisbane-based GP, says diet and exercise are always recommended for people at low risk of cardiovascular disease.

However, for those at high risk it's never the case of choosing one or the other and statins are always prescribed to reduce the risk of someone dying from heart disease, he said.

"As the risk increases you become a lot more aggressive in terms of interventions because at the end of the day someone who is at high risk you want to do everything you can to reduce the chances of them having a severe heart attack or stroke," Dr Kidd said.

"We know that whatever risk a person has got if you give them a statin you reduce their risk of a heart attack by a third."