Smoothies: nutritionists' dream or dentists' nightmare?

18 October 2018

Delicious and packed with goodness, fruit smoothies may seem to be the perfect fast-food for the health-conscious consumer. But beware: your teeth and gums may suffer the effects if you indulge in too many, too often.

A leading nutritionist has sparked controversy within the health community by calling for fruit smoothies to count as two portions of our 5-a-day quota. Designating smoothies as two portions of fruit rather than one would help more people meet their 5-a-day target, argues Dr Carrie Ruxton.


In her article in the June issue of the British Nutrition Foundation's journal Nutrition Bulletin, she states, ‘Smoothie recipes contain at least one 80g portion of mashed fruit plus a portion of juice, and are nutritionally equivalent to two portions of fruit.’

Dr Ruxton contends that the sugar content of smoothies is no greater than the fruit in its original form, and the nutritional benefits offered by smoothies "far outweigh any risks". However, the British Dental Health Foundation (BDHF), among others, has voiced concern about the potential damage that the high sugar content of some fruit smoothies could inflict on teeth and gums.

Acid attack on teeth

‘While fruit smoothies can be a good way to get people to consume more fruit, the high concentration of sugar and acids means that they can do real damage to the teeth if sipped throughout the day,’ warns Dr Nigel Carter, chief executive of the BDHF. ‘Every time you sip on a fruit smoothie your teeth are placed under acid attack for up to an hour, so constantly sipping on these drinks can cause the protective enamel to erode, causing pain and sensitivity. It can also lead to decay.’

According to dietitian Azmina Govindji, ‘Most good brands of smoothies will be sugar and fat free. The sugar in them comes from the real fruit and unsweetened fruit juice, though the amount of sugar you get from a serving is high. Since they are sugar in liquid form, smoothies will contribute to tooth decay, especially if you sip them during the day between meals. Ideally, drink them with a meal.’

The BDHF advises people to brush their teeth before (rather than after) drinking fruit juice and smoothies, as this helps to protect against the damaging effect of the acid contained in the drink.

One portion or two?

In addition to the high sugar content, some health experts are worried about the increased calorie content of smoothies that contain ingredients such as whole-milk yoghurt, as well as the reduction in fibre as a result of the juicing process. Dr Ruxton counters that smoothies ‘are significantly higher in fibre, vitamin C and antioxidants than juices, and meet the criteria to make a labelling claim for fibre content’.

The Food Standards Agency (FSA) advises that fruit juice can count as only one portion of our 5-a-day quota regardless of how much we consume ‘because you don't get the same nutritional benefits from juice as you get from whole fruit and veg’. The FSA does concede, however, that ‘some smoothies may count as more than one portion if they contain all of the edible pulped fruit and/or vegetable’.

According to Azmina, ‘The national guidelines suggest that a smoothie counts once a day and you can't count it on the same day as fruit juice. However, many smoothies have the nutritional equivalent of two portions, so in practice you could be doing better than you think.’

Go for variety - and make your own!

Azmina concludes that smoothies are a great way to help you towards your 5-a-day as long as you make sure you also eat a variety of fruit and veg.

She offers the following additional tips:

  • Split your smoothie so you have it in two sittings – one with each of your main meals.
  • Make your own smoothies with any fruit, fruit juice, yoghurt and skimmed milk – great for using up fruit that has become over-ripe.
  • Remember, the more varied the colours, the wider the range of nutrients. So if you enjoy smoothies regularly, choose different-coloured ones to add variety.

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