Food Healthy

Sales of salmon, blueberries, walnuts and spinach, and the likes of more esoteric produce such as goji berries and spirulina, have soared in the last two years as books, supermarkets and the media extol their particular health benefits. Eat them, we're told, to help reduce the risk of cancer and heart disease.

These so-called 'superfoods' are often promoted as having almost magic health-giving properties. But is the magic all in the marketing? And are we being bamboozled into buying expensive berries and exotic fruit when they're no better for us than a crunchy English apple or a homely cauliflower?

What's the science?

There is no official or scientific definition of the term 'superfood'. It's applied to foods ranging from oats to walnuts, spinach to yoghurt, turkey to watercress. Meat and fish contain proteins and other nutrients. Fruit and vegetables also contain essential vitamins and minerals and phytochemicals - bioactive non-nutrient components - that are good for health. Labelling some as 'superfoods' could give the impression that they are more health-enhancing than others.

Generally, fruits and vegetables given a 'superfood' tag are high in antioxidants such as vitamin C. Flavonoids, responsible for the colour of dark fruits such as blueberries, and other phytochemicals such as betacarotene, are also known for their antioxidant properties, which is why brightly coloured fruit and vegetables are considered especially beneficial.

For the past decade or so prevailing opinion, based on scientific research, has been that because antioxidants are especially effective at combating free radicals - harmful molecules that damage cells and DNA and can contribute to ageing, heart disease and cancer - they make fruit and vegetables particularly good for health. But phytochemicals, also present in less brightly coloured fruit and vegetables not classed as superfoods, could also act in other ways to protect against disease. Scientists investigating the different ways phytochemicals can act believe too much importance may have been attached to antioxidant activity, and not enough to the other beneficial effects of phytochemicals.

Soar-away sales

Because the term 'superfood' has been widely used and understood to mean extra-healthy, and because certain foods have become more widely available, sales of so-called 'superfoods' have increased dramatically in the past few years.

Blueberry sales in the UK have risen by 132 per cent since 2005, with shoppers spending £95m on blueberries in a single year. Spinach sales went up from £32m worth to £42m, and salmon sales went up 31 per cent during the same period.

Perhaps to encourage sales, yet more foods, such as watercress, are being termed as 'superfoods'.

Berry pricey

It's no bad thing if we all eat more watercress, but the most heavily promoted so-called 'superfoods' are exotic imports such as pomegranates, blueberries, avocados, mangoes and goji berries. Compared to home-grown apples they cost more and come with a larger carbon footprint because of the CO2 produced by their journey to the shops.

There is as much vitamin C in six flavonoid-packed blackberries - free from a hedgerow near you at certain times of year - as in one lemon

While blueberries do grow in the UK, most are imported to meet demand. Yet our home-grown blackcurrants have a similar phytochemical content and there is as much vitamin C in six flavonoid-packed blackberries - free from a hedgerow near you at certain times of year - as in one lemon.

Backing claims

Following EU legislation introduced in July 2007 to prevent unsubstantiated health claims being made on foods, terms such as 'superfood' will have to be backed by evidence explaining why the food is healthy. This could be difficult as there is no official definition of the term 'superfood'.

There is a two-year period before the legislation comes into force, during which food producers must prove to the European Food Safety Authority that any claims can be backed up by evidence. Products that are high in calcium, for instance, can legitimately claim that calcium is good for bones. Oats have been shown to help reduce cholesterol as part of a low-fat diet and this claim could be made on a product.

A healthy diet

No food is 'super' on its own

Even if certain foods were proved to be much higher in nutrients than others, it's important to eat a range of foods. "A handful of berries won't be enough to make you healthy and well," says the British Nutrition Foundation's nutrition scientist Anna Denny, who believes that "we should eat a rainbow-coloured diet. No food is 'super' on its own. There are so many benefits in all fruits and vegetables. There is no such thing as 'superfoods', only super diets."

Some of the latest research by leading university-based scientists suggests that it isn't just the antioxidants in fruit and vegetables that provide protection against disease. There is strong evidence that the phytochemicals in broccoli can help protect against bowel cancer by acting in other ways. These same phytochemicals are also contained in cauliflower, sprouts and cabbage which haven't been accorded the same 'superfood' status as broccoli.

Eating exotic foods may offer health benefits we don't yet understand. Just because they're eaten in other parts of the world where there is a lower incidence of certain diseases, however, doesn't mean that they'll give the same protection to those following a very different diet and lifestyle in the UK.

It may also be that what's important is how a particular food works in combination with other foods. Eating one so-called superfood to the exclusion of other fruit or vegetables may limit the benefits.

Beet that

On the plus side, the 'superfood' tag has done wonders for the humble home-grown beetroot. Most people fail to meet the target of five portions of fruit and vegetables a day. As long as we don't reject some fruit and vegetables in favour of more fashionable ones, publicity that encourages consumers to eat more fruit and vegetables is to be welcomed, say even sceptical nutritionists.