So called 'functional foods' claim to boost our health by actively working to help our bodies, but are they really wirth trying? Shoptalk investigates.

CAN food make you fit? As we struggle to get over our festive excesses, it's a nice thought. We all know that eating the right food can help keep us healthy, but now we also have a range of new foods to choose from, the so called "functional foods".

These are foods that are not just good in themselves but which contain added extras to improve our health. And as well as self-inflicted woes, we still have a lot of winter and all its bugs and germs to face.

Worth trying? Well, the official verdict seems to be yes and no.

CHOLESTEROL LOWERING SPREADS

High cholesterol levels are a known risk factor for heart attacks, so bringing it down can only be good.

The manufacturers of Benecol and Flora Pro Activ add plant sterols or stanols to their already light spreads. General expert opinion is that these are helpful. Various studies have proved they can be very effective. BUT they're not an excuse to stuff yourself on other unhealthy food. They are most effective as a small part of a healthy eating and exercise lifestyle.

HOW MUCH?

Benecol Light spread 500g £3.99, Flora Pro Active spread with olive oil, £4.08 - compared with Flora diet spread 500g at just 91p.

CHOLESTEROL LOWERING YOGHURTS

Flora Pro Activ low fat yoghurt also has added plant sterols

Benecol strawberry yoghurt drink has plant stanol ester

HOW MUCH?

Benecol drinking yoghurt 6 x 67.5g £3.28, Flora Pro Activ 4 x 100g £2.48

PROBIOTICS

Probiotics are natural organisms which aid digestion. The "friendly bacteria" of the Yakult ads. Yakult was the brainchild of a Japanese microbiologist who discovered the importance of the right sort of bacteria in your insides. Probiotics top up the good bacteria and keep the bad ones at bay. If you want an idea of scale, each tiny bottle of Yakuilt contains 6.5 billion bacteria. Gulp.

Opinion on the health benefits of these is more divided. "Probiotic bacteria may be beneficial in certain circumstances, but the evidence for this is patchy. There's no reliable research to prove that they help your general well-being," says a report in this month's Which?

They might well help those suffering from stomach disorders - whether it's a brief spell of gastro enteritis, or the long term symptoms of irritable bowel syndrome. But if your insides are nice and fit and healthy to begin with, these probably won't do much for you.

HOW MUCH?

Yakult fermented milk 7 x 65ml £2.45.

Sainsbury's probiotic orange juice 600ml (4 x 150ml daily dose bottles) £1.79. Compared with Sainsbury's orange juice 75p for 1 litre.

Muller Vitality Range offers low fat pre and pro biotic yoghurt and yoghurt drinks with added Omega 3 - the nutrient found in fish and which has been shown to help improve children's learning.

Danone Activia yoghurt with Bifidus Digestivum 4 x 125g £1.38.

Muller Vitality 6 x 150g £1.88.

BLOOD PRESSURE

LOWERING YOGHURTS

As well as the green range for lowering cholesterol, Flora Pro Activ now has a pink topped range containing ameal peptide, which can help lower blood pressure.

Flora Pro Activ yoghurt drink 4 x 100 £2.48.

IMMUNE BOOSTING YOGHURTS

Danone Actimel contains casei imiunitas, said to boost the body's immune system.

HOW MUCH?

4 x 125g yoghurt £1.38.

FUNCTIONAL FRUIT JUICE

Once upon a time fruit juice was just, well, fruit juice and considered healthy enough in its own right. Not any more. Now you can get fruit juice with added vitamins, added fibre and added calcium. Tropicana Essentials with added calcium has the same amount of calcium as milk. So drink a glass of Tropicana and you get the Vitamin C and the calcium - twice the goodness. And more than twice the price too. Cheaper to buy ordinary fruit juice and a pint of milk. BUT it is a very easy way of getting calcium into people who are lactose intolerant or - like many children - just don't like milk.

HOW MUCH? Tropicana Essentials £1.99 a litre.

SHOULD YOU BOTHER?

Many of these functional foods have proved to be successful. However, they are not miracle cures. You can't stuff your face, sit around all day, take no exercise and then think one tiny bottle of yoghurt is going to make a difference. It's not. But if you're prepared to make an effort, many of these will be a real help.

BUT they are, on the whole, expensive - much more expensive than their ordinary equivalents. And they all - especially the dinky little drinks - emphasise that you have to take them every day. It will get expensive.

In the long run, it would probably be cheaper and just as healthy to spend that extra money on more fresh fruit and veg or on a new pair of trainers - as long as you use them. Christmas is over. Sorry, when it comes to health and fitness, there are no magic short cuts.