The healthiest foods aren’t usually the ones that tempt our tastebuds or turn our heads.

But two new additions to the supermarket shelves could be about to prove that theory wrong.

A healthier and sweeter variety of broccoli goes on sale today – alongside eye-catching crunchy carrots in colours such as purple, yellow and amber.

The super-broccoli is packed with a plant chemical credited with warding off cancer and heart problems, and is said to taste better than other varieties.

The Beneforté broccoli contains up to three times as much glucoraphanin – a compound which, when broken down within the body, is thought to provide protection against prostate and other cancers and improve heart health.

What’s more, raising levels of the plant chemical reduces broccoli’s sharp flavour, making the vegetable taste less bitter.

The scientists behind it, from the John Innes Centre and Institute of Food Research in Norwich, have spent almost 20 years working out why vegetables such as broccoli are so good for us and how to make them even healthier.

Coloured carrots

The Beneforté variety, which goes on sale at Marks & Spencer stores around the country today and costs no more than normal broccoli, was produced by crossing a common variety with a wild one that contains exceptionally high levels of health-boosting glucoraphanin.

The chemical is also found in cauliflower and in Brussels sprouts, but at much lower levels.

Dr Simon Coupe, M&S agronomist, said: ‘It takes a long programme of growing to bring these products to market and we’re proud to be able to be first to launch this product.’

Meanwhile, children who are reluctant to eat their greens may now be tempted to tuck into purple, orange, tangerine, white, yellow, cream and amber instead.

The multicoloured carrots have been grown naturally in Norfolk after being cultivated from old varieties which were no longer produced commercially because orange has been the favoured colour for hundreds of years.

The carrots, which have their foliage still attached, will be sold as a mixed selection in branches of Tesco across the UK from today, costing £1 a bag.

Tesco vegetable buyer Steve Williams said: ‘Some people who have tried them have said that the white and yellow ones are slightly sweeter than the orange variety and are also crunchier.’

Until the 16th century carrots were usually purple or yellow, although it was not uncommon to find other variations.