There’s nothing like a fruit juice to leave you feeling cleansed, nutrient-pumped and virtuous. Yes, mineral water is calorie-free, but it does not have the detoxing, immune system-boosting properties that you are supposed to get from a glass or bottle of something that has been freshly squeezed, pulped or pressed. So taken are we with the concept of juicing our way to looking and feeling good that we collectively guzzled our way through 34m litres of smoothies last year.

This sounds like good news for a nation that persistently fails to meet the recommended target of five portions of fruit and vegetables a day, managing, on average, only a paltry two servings. Surely our juiceaholic tendencies are a step in the right direction? Some experts think not, claiming instead that we are being misled by the marketing practices of the soft-drinks industry into thinking the more smoothies and juices we drink, the better.

“It is a misconception to think that these drinks make up for other dietary failings,” says Catherine Collins, the chief dietician at St George’s hospital in south London. “Actually, they are nowhere near as good for you as consuming a fruit or vegetable in its whole, unaltered state.”

During the juicing process, fibre, pith and sometimes skin are removed. “These are important, nutrient-rich parts of a fruit or vegetable, and one of the reasons they are so good for us,” says Anna Denny, a nutrition scientist at the British Nutrition Foundation. “A whole apple or mango is far more beneficial than a juiced one.” It is for this reason that guidelines produced by the World Health Organisation and the Department of Health state that a smoothie or glass of juice should constitute no more than one of the recommended daily fruit and vegetable servings.

There are other potential risks linked to high juice and smoothie consumption, too. According to Denny, once a fruit is squeezed, its natural, healthy sugars become as potentially harmful to teeth as ordinary sugar.

“Natural sugars, called intrinsic sugars, are locked within the cells of a fruit and are the kind that we don’t need to cut back on. However, those sugars are released when a fruit is juiced, and they become partly extrinsic sugars, which are known to promote tooth decay.” In fact, these sugars, combined with the acidity of many fruits and vegetables, mean that a juice habit is a potential dental disaster.

“Every time you drink something acidic, the enamel on your teeth is softened and loosened temporarily, which can be damaging,” says Carol Coates, a dental adviser at the British Dental Health Foundation. “Sipping juice over a prolonged period will extend the time that your teeth are exposed to these acids. Ideally, drink juice in one go.” Coates also advises rinsing your mouth with water afterwards and not brushing your teeth while the enamel is still loose. “You need to leave time for your saliva to neutralise the acids, so that your teeth can be remineralised, which takes about an hour,” she says.

The American Academy of Pediatrics is concerned that, in addition to damaging dental health, too many juices or smoothies – often with added sugar and dairy foods – are supplying “liquid calories” that are fuelling the obesity epidemic among preschool children. The drinks manufacturers, however, insist their products are nothing but a health shot. For those few that combine only whole crushed fruit and juice, this is true, but it doesn’t apply to most commercial varieties.

Ultimately, it’s better to eat the fruit, the whole fruit and nothing but the fruit.

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