Health-conscious shoppers have made smoothies "the drinks success story of the 21st century" with an explosive growth in popularity in the past five years, according to a report.

Sales of the crushed fruit drinks rose 523 per cent in the five years to 2006 and the number of smoothies sold is expected to almost treble by 2011.

Mintel, which published the report, said ordinary smoothies made up most of the market but "functional" products with ingredients such as ginseng and echinacea had risen by 2,350 per cent in the five years to 2006.

Smoothies enjoy a spurt of growth in January as people follow new year resolutions to become healthy and machines for making the drinks at home were heavily promoted at Christmas.

But dietitians say the public should be wary about drinking too many smoothies: they can be high in sugar and only ever count as one of the five portions of fruit and vegetables the Government recommends people eat daily. Liquidised fruit also loses the fibre that helps make it so healthy.

Sales at the biggest smoothie maker, Innocent, leapt 168 per cent last year to £80m, according to figures from The Grocer trade magazine. Mintel said the popularity of the drinks had been helped by the introduction of one-litre cartons that usually contain fruit juice. Britons drank 34 million litres of smoothies last year, compared with 6.3 million litres in 2001. By 2011, Mintel believes we will drink almost 100 million litres. The price of smoothies is expected to drop as sales rise. Last year the smoothie market was worth £134m.

"Smoothies have been the true drinks success story of the 21st century and are clearly no longer a niche market," said Vivianne Ihekweazu, senior market analyst at Mintel. "Healthy eating, and the five-a-day fruit and vegetable campaign, has been the driving force behind continuing rates of exceptional growth."

Despite the huge growth in the market, less than a third of the adult population currently buys smoothies. The 15-19 and 25-34 age groups are the most likely to reach for one, which the report believes may be due to their busy lifestyle or need for a hangover cure.