Even though the effects of diet on atherosclerosis in humans is not clear, eating fruit and vegetables is known to protect against heart disease.

New research from the U.S. suggests that different coloured vegetables contain different minerals and may prevent hardening of the arteries.

The researchers from Wake Forest University School of Medicine, found 38% less build up of fatty deposits in the arteries of mice who were fed a mixture of vegetables, including carrots and peas.

Lead researcher Michael Adams, says though everyone knows that eating more vegetables is supposed to be good for you, no one has shown before that it can actually inhibit the development of atherosclerosis.

In a study using specially bred mice that rapidly develop atherosclerosis, the researchers found that a mixture of five common vegetables reduced hardening of the arteries by 38 percent compared to animals eating a non-vegetable diet and say this suggests that a diet high in vegetables may help prevent heart attacks and strokes.

Half of the mice in the study were fed a vegetable-free diet and half got 30 percent of their calories from a mixture of freeze-dried broccoli, green beans, corn, peas and carrots, five vegetables among the top-10 vegetables in the United States based on frequency of consumption.

After 16 weeks the researchers measured the cholesterol content in the blood vessels and estimated that plaques in the arteries of the mice were 38% smaller.

There were also modest improvements in body weight and cholesterol levels in the blood.

According to Adams it is unclear exactly how the high-vegetable diet influenced the development of plaques in the artery walls but the results indicate that a diet rich in green and yellow vegetables inhibits the development of hardening of the arteries and may reduce the risk of heart disease.

Adams said there was there was a 37% reduction in serum amyloida, a marker of inflammation in mice which suggests that vegetable consumption may inhibit inflammatory activity and it is well known that atherosclerosis progression is intimately linked with inflammation in the arteries.

There have been many studies in humans which have shown that a high-vegetable diet is associated with a reduced risk of cardiovascular disease, as well as with reductions in blood pressure and increases in "good" cholesterol.

The team believe this is the first study to address the effect of increased vegetable consumption on the development or progression of atherosclerosis.

Despite compelling evidence supporting the health benefits of increased vegetable consumption, Adams says intake remains low.

The research is published in the current issue of the Journal of Nutrition.