The new `functional foods' are not just healthy alternatives. They claim to have positive health benefits. But is it true? asks Meg Carter
t has been hailed as the most significant development in food in 25 years: food that not only tastes good, but has an active, beneficial effect in lowering the risk of disease. "Functional foods" are the new generation of health products currently invading the supermarket shelves.

Foods with added vitamins and minerals are nothing new: vitamins such as A and D have been added to margarine, for example, for years. However, as nutritional research moves on, so too do food companies' marketing strategies. While in the Seventies and Eighties the emphasis was all on food without things - low fat, fat-free and sugar-free - in the Nineties, attention has focused on food with a bewildering array of hi-tech nutritional additives.

Gaio, a yoghurt-like food launched last year, contains "a special, natural ingredient" - the Causido culture which Gaio's manufacturer, MD Foods, claims helps to reduce cholesterol. Rival food company Nestle has developed LC1 - chilled foods available as a milk drink or potted in strawberry and vanilla flavours. LC1 also contains its own ingredient X: Lactobacillus acidophilus 1 - a culture which "survives the gastric acid barrier in your stomach" to stimulate the immune system and "help stop harmful bacteria sticking to the intestinal walls."

The latest arrival is Yakult - a fermented milk drink from Japan which contains a bacterium called lactobacillus casei shirota. Yakult, launched in the UK last month, eases digestion by maintaining the balance of bacteria in the intestine, its manufacturer Yakult Honsha claims.

"Really, the term functional foods is a misnomer," says Dr David Richardson, chief scientist at Nestle and chairman of the Food & Drinks Federation's working party on functional foods. "All foods are functional in terms of providing nutrients." But these go further, he says - by offering a beneficial effect on a physiological process. The good news for food manufacturers is that this has coincided with Government efforts to persuade the nation to adopt a healthier diet. According to research for MD Foods, 32 per cent of the population claims to be "health-oriented" and tries to live healthily while 36 per cent do nothing but believe they should.

Functional foods are therefore a logical step from the food maker's point of view. However, the claims associated with many of these new generation health food products are causing concern.

Last December, the Advertising Standards Authority rebuked SmithKline Beecham for its claims about Ribena Juice & Fibre. The implication that the drink could lower plaque build-up on artery walls was not supported, the ASA ruled. Just last month, the ASA also upheld three complaints against Gaio's advertising. The Authority ruled that the clinical tests referred to were too small to support the cholesterol-lowering claim; an accompanying graph exaggerated the documented effects and the culture itself was not unique - as claimed - for Gaio. It is now investigating Gaio's sister product Pact - a reduced fat spread containing "omega-3" which has been linked to the prevention of heart disease.

"The problem is that it is difficult to advertise these products without exploiting the public's credulity as they can be highly complex to explain," ASA spokesman Graham Fowler said. "The mechanics governing arterial plaque build up are extremely complex."

Under ASA guidelines, advertisers must not make exaggerated or unsubstantiated claims. Nor should they exploit lack of knowledge or mislead through ambiguity or omission. "Before an advertiser can make a claim it must hold documentary evidence to back it up. We expect rigorous trials," Fowler explains.

His concern is shared by the National Food Alliance which has made a number of complaints about health claims. Vice chairman Jack Winkler acknowledges that some functional foods can do good. But he questions the grounds on which claims are made: "What evidence is required should be examined - whether one study paid for by the company lasting six weeks is sufficient, or whether there should be an international, scientific consensus."

Use of words such as "promotes" or "maintains" rather than "prevents" enables slick marketers to sidestep strict regulations on health claims. This makes it unclear whether these products justify the premium prices they command, he said. Then there's the effect on attempts to improve the nation's health, Winkler adds. "Government strategy is to rebalance the national diet. The problem with these foods is they promise a single food solution."

Not so, according to Dr Richardson who says Nestle is positioning LC1 as a product for the whole family, to be eaten daily as part of a healthy, balanced diet. "Our claims are supported by a comprehensive, scientific research programme," he says. "I have no evidence to suggest there is consumer confusion in the market place." Henrik Nygaard, marketing manager of MD Foods which makes Gaio, adds: "We do not want to get people away from living a healthy diet - it's the only way we can sell our product."

Some manufacturers are keen to distance themselves from the functional food debate. Yakult eschews the term "functional food". "Our product has been around 60 years. Yet we have launched in the UK into a lot of controversy," a spokeswoman says. "If we could have chosen another time to launch [here] we probably would have."

Jack Winkler foresees an upward spiral of functional food claims. Without voluntary regulations on product claims, he predicts "a hi-tech, 21st century version of 19th century medical quackery and miracle cures." Others share this fear, which is why the food industry has now joined lobbying groups in a consultation process with the Government to decide if - and how - functional food marketing should be regulated. There is a simple reason for this new spirit of co-operation. Get it wrong, and the food makers risk killing the golden goose before it lays.