Sales of superfoods, the nutrient-rich stars of the fruit and vegetable world, are booming as shoppers seek to eat their way to good health, new research shows.

During the past two years, Britons have devouredmore blueberries, spinach, broccoli, salmon and walnuts, sending sales up between 26 and 132 per cent.

The figures from the market research company AC Nielsen are further evidence that consumers are taking on board the advice dished out by nutritionists such as Gillian McKeith, who have championed little-known foods like the goji berry and blue-green algae.

Barely a week passes without a new berry or fruit, usually exotic and colourful, being trumpeted as a superfood. More traditional vegetables such as spinach and beetroot are also being prized by cooks because of their high vitamin and antioxidant content.

Berries, however, have been the biggest stars of the trend for " superfoods", and between 2005 and 2007 blueberry sales more than doubled - up 132 per cent - to £95m a year. "Blueberries contain antioxidants which help with circulation, keeping the heart healthy and maintaining youthful-looking skin, explained Jonathan Banks, Nielsen's business insight director. "These are all important to today's health and youth-conscious consumer".

During the same period, soy drinks - an alternative to dairy products - jumped 50 per cent to £70m while another "healthy" drink, green tea, rose 45 per cent to £16m. More traditional ingredients such as spinach, salmon and walnuts all found themselves piled up in larger amounts in shopping baskets.

The greater variety of tomatoes, such as cherry, vine and plum, was credited for an £86m spike in sales, which increased by 16 per cent to £625m. Mr Banks said: "There are a lot of varieties of tomato available, and consumers are willing to 'trade up' to more expensive varieties."

Sales of walnut kernels were up 36 per cent year on year at Waitrose, after a surge at the end of last year when sales leapt 80 per cent year on year. The grocer's nutrition manager, Moira Howie, said: "Walnuts are good because they are high in polyunsaturated fats, as well as providing omega 3 fats, vitamin E and folic acid."

Judy More, of the British Dietetic Association, said she was not surprised superfoods had been popular because of the media coverage they had received. But she urged the public to eat a variety of fresh, seasonal produce, which was richest in nutrients.

She said: "The British Dietetic Association would say all foods which provide nutrients are superfoods in their own way and a healthy diet is made up of a variety of superfoods. We areconcerned that people may be spending a lot of money on blueberries when they might be able to get a lot of fruit and veg for the same price. We would say eat the widest variety of fruit and veg you can, but eat them while they are in season."

Nielsen's data is taken from its Scantrack service, which monitors checkout scanners at 74,000 shops.

Essential ingredients

* VITAMIN C

Blackcurrants, kiwi fruit, tomatoes, green and red peppers, oranges, lemons, grapefruit, strawberries.

* CAROTENES

Oranges, carrots, sweet potatoes, red peppers, spinach, broccoli, swede, apricots, peaches, honeydew melon, mango, berries.

* VITAMIN K

Green, leafy vegetables.

* FOLIC ACID

Brussel sprouts, asparagus, fresh beetroot and leafy green vegetables such as spinach.

* VITAMIN E

Avocado, almonds.

* ANTHOCYANINS

All berries and beetroot.

* QUERCETIN

Tea, onions, garlic, broccoli, apples, grapes, red wine, cranberries.

* CATECHINS

Tea.

* LYCOPENE

Tomatoes.

* ISOFLAVONES

Soya.

Source: British Dietetic Association

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