THE health benefits of eating carrots could be increased by a quarter by waiting until they are cooked before chopping them up, a study has found.

Scientists at Newcastle University found that cutting a carrot after boiling it could boost its anti-cancer properties by 25 per cent.

The study, carried out by Dr Kirsten Brandt and researcher Ahlam Rashed, from the University's School of Agriculture, Food and Rural Development, found that ''boiled-before-cut'' carrots contained 25 per cent more of the anti-cancer compound falcarinol than those that were chopped up first.

And the naturally occurring sugars which are responsible for giving the carrot its distinctively sweet flavour were also found in higher concentrations in the carrot that had been cooked whole - meaning the vegetable tastes better as well as being healthier.

The health benefits of falcarinol was first discovered four years ago when Doctor Brandt found rats fed on a diet containing carrots or isolated falcarinol were a third less likely to develop full-scale tumours than those in a control group.

The latest study found that when carrots are heated, their composition changes. As the heat kills the cells of the carrot, they lose the ability to hold on to the water inside them, increasing the concentration of falcarinol as the carrots lose water.

But the heat also softens the cell walls, allowing water-soluble compounds such as sugar and vitamin C to be lost through the surface of the tissue and resulting in the leaching out of other compounds such as falcarinol. Since the carrot loses water and sugar, the weight per carrot is also reduced.

If the carrot is cut before being boiled, the surface area becomes much greater and so also the loss of nutrients and taste compared with one that is whole when it is boiled.

The naturally occurring sugars which are responsible for giving the carrot its distinctively sweet flavour were also found in higher concentrations in the carrot that had been cooked whole - meaning the vegetable tastes better as well as being healthier.

''Chopping up your carrots increases the surface area so more of the nutrients leach out into the water while they are being cooked,'' Dr Brandt said.

''By cooking them whole and chopping them up afterwards you are locking in both taste and nutrients so the carrot is better for you all round.

''We all want to try to improve our health and diet by getting the right nutrients and eating our five-a-day. The great thing about this is it's a simple way for people to increase their uptake of a compound we know is good for you, all you need is a bigger saucepan.''

The team also carried out a blind taste test on almost 100 people comparing the taste of ''boiled-before-cut'' versus ''cut-before-boiled'' carrots. The response was overwhelming with more than 80 per cent saying that carrots cooked whole tasted much better.