Eating apples, pears, bananas or other fruits and vegetables with white flesh may help protect against stroke, a Dutch study concludes.

The study in Thursday's online issue of the journal Stroke: Journal of the American Heart Association looked at the associations between colour groups of produce and stroke for about 20,000 adults over 10 years. Apples are high in dietary fibre and flavonoids, which has been associated with lower risk of stroke, the researchers said. Max Rossi/Reuters

There were four colour groups for the fruits and vegetables, such as:

• Green: Dark leafy vegetables, cabbages and lettuce.
• Orange/yellow: Mostly citrus fruits.
• Red/purple: Mostly red vegetables.
• White: 55 per cent apples and pears; bananas, cauliflower and cucumber.

It's thought that the edible part of fruits and vegetables contain beneficial carotenoids and flavonoids that provide antioxidants.

Apples and pears are high in dietary fibre and flavonoids, which have been associated with lower risk of stroke, the researchers said.

During the 10 years of followup, 233 strokes were recorded.

The risk of stroke was lower among those who said they had a high intake of white fruits and vegetables compared with those with a low intake, Linda Oude Griep, the lead author of the study and a postdoctoral fellow in human nutrition at Wageningen University in the Netherlands and her colleagues found.

Each 25 gram per day increase in white fruit and vegetable consumption was associated with a 0.91 times lower risk of stroke.

The other colour groups weren't related to stroke.

"To prevent stroke, it may be useful to consume considerable amounts of white fruits and vegetables," Griep said in a release, adding it may be too early to advise patients to change their diet based on the initial findings.

An editorial accompanying the study said a validated and detailed food frequency questionnaire was used, but its reliability is low.

The reduction in stroke risk might be caused by the generally healthier lifestyle of those who ate a diet rich in fruits and vegetables, Dr. Heike Wersching, of the Institute of Epidemiology and Social Medicine at the University of Munster, in Germany, said.

Wersching called the work "interesting".

"If replication is successful in independent studies and countries the time for an 'apple a day' clinical trial has come," Wersching concluded.

The cost of data analysis for the study was funded by the Dutch Product Board for Horticulture.