Eating three apples a day can significantly cut the risk of death from coronary heart disease, say scientists.
Apples are high in fibre
The fibre in apples and other fruits helps prevent heart disease by lowering cholesterol levels.
The findings are part of a US study published in the Archives of Internal Medicine.
It reinforces other research which has shown the health benefits of a diet rich in fibre.
Scientists, who carried out the research, said people who eat 10 grams of fibre daily, reduce their risk of heart attack by 14% and their risk of dying from coronary heart disease by 27%.
Grains and cereals
A medium-sized apple contains about 3 grams of fibre, a slice of whole wheat bread contains 1.5 grams and a stalk of broccoli about 2.7 grams of fibre.
Fibre found in fruit, vegetables, grains and cereals lowers blood pressure and cholesterol levels, according to the article.
The team found the health benefit of fibre was strongest when it came from fruit and cereals, rather than vegetables.
They say the reason may be because common starchy and heavily processed vegetables, such as sweetcorn and peas, are poor in nutrients but high in sugars that can lead to diabetes and heart disease.
"Our results suggest that dietary fibre intake during adulthood is inversely associated with CHD risk, said study author Mark Pereira, formerly of Harvard University in Boston, and now at the University of Minnesota.
"Therefore, the recommendations to consume a diet that includes an abundance of fibre-rich foods to prevent coronary heart disease) are based on a wealth of consistent scientific evidence."
Fibre in the diet has been found to lower blood pressure, cut blood levels of artery-clogging lipids and improve insulin sensitivity.
The research team pooled the results of 10 US and European studies of more than 330,000 adults.
Of the participants, 5,249 developed heart disease and 2,011 died from the disease during the six to 10 years of follow-up.
The British Heart Foundation (BHF) recognises the importance of fibre in our diet, recommending 30 grams a day, but suggests it should come from a variety of sources.
In response to the US findings, BHT head of medical information Belinda Linden said: "Several studies have examined the link between fibre intake and heart disease but these have proved inconclusive, partly because some diets were also low in fat.
"Fibre probably does not have a direct effect on heart disease, but adds bulk to the diet and fills you up, making you less likely to snack on fatty foods."