Are functional drinks safe for kids?

Experts explain how beverages like sports and energy drinks can affect children

A bottle of vitamin water contains an average of five or six tablespoons of sugar, says KKH dietitian Jasly Koo. A child aged between three and six should have just three tablespoons of sugar a day, according to HPB.
A bottle of vitamin water contains an average of five or six tablespoons of sugar, says KKH dietitian Jasly Koo. A child aged between three and six should have just three tablespoons of sugar a day, according to HPB.ST FILE PHOTO

Besides sports and energy drinks, children can choose from a wide array of functional drinks to replenish their bodies, including protein shakes and vitamin water.

These are easily available at supermarkets, convenience stories and minimarts here.While they are not considered harmful for most people, a question is whether they are advisable for children.

Experts give the low-down on four types of functional beverages that active children may consume.


These isotonic drinks are formulated to replace water and minerals lost through perspiration. Many contain B vitamins to aid in energy metabolism, and vitamins C and E to guard against the effects of oxidation.

  • What active kids need

  • If your child is physically active - through sport or exercise - his body will need more energy, as well as fluids and minerals.

    Here are some tips on the nutrition needs of active children after they sweat it out.

    • Ask them to drink water after prolonged physical activity - even if they say they are not thirsty. Children and adolescents who have yet to enter puberty have a proportionately larger body surface area than adults, as well as a lower sweating capacity. So, their bodies tend to get overheated more easily.

    • Get them to replace minerals by taking mineral water, which has electrolytes.

    •Fluid replacement drinks, such as sports drinks, may benefit children engaged in more than an hour of exercise. But ask them to stay clear of products with caffeine, such as energy drinks.

    •Ask them to consume food with vitamins B3, B5 and B6 to support glucose metabolism. Include vitamins C and E to neutralise free radicals that are produced during exercise.

    •Encourage them to consume a protein-rich drink like milk, or eat a protein-rich meal to support muscle recovery.

    •Prepare nutrient-dense snacks for them to munch on. These should contain a good dose of energy, protein, vitamins and minerals.

    Examples include:

    1. A sandwich with cheese, tuna, egg or lean meat, plus salad greens

    2. Cereal

    3. Crackers with cheese slices, peanut butter or avocado

    4. Fresh or dried fruit, plus mixed nuts

    5. Meat or vegetable pau

    • Give a single multivitamin when a child is not eating enough. Avoid dietary or sports supplements that claim to enhance sporting performance, as there is a lack of clinical evidence regarding their long-term benefits.


Isotonic drinks are helpful for athletic people who sweat profusely.

They are not advised for sedentary children, said Ms Phuah Kar Yin, principal dietitian at KK Women's and Children's Hospital (KKH).

"They provide unnecessary calories which will lead to excessive weight gain," she said.

Dr Ang Poon Liat, consultant paediatrician at Thomson Paediatric Centre, noted that taking sports drinks in place of water is now considered a contributing factor to obesity. About 12 per cent of students in primary and secondary schools and junior colleges here are obese.


The "kick" in these drinks originates from caffeine and sugar, which are absorbed rapidly to provide instant energy and performance.

The amount of caffeine found in these drinks tends to be high - as much as 141mg per serving. In comparison, an average cup of coffee contains 133mg of caffeine.

The caffeine content in energy drinks may also be higher than stated on the label, according to the American Academy of Paediatrics.

This is because Guarana, a plant extract that has caffeine, is commonly used in these drinks, but often listed separately from caffeine in the ingredient list.

Caffeine intake can disrupt a child's sleep at night or affect sleep quality. In rare instances, it can cause short-term ill effects in children, like heightened anxiety and irregular heartbeat, said Ms Phuah. In the long run, it can affect the development of the child's nervous and cardiovascular systems, she added.

Dr Ang warned that both caffeine and sugar are also addictive.


The vitamins in these beverages may be synthetic or extracted from plants. They can be grouped into water soluble types, such as vitamin C; and fat-soluble ones like vitamins E and A.

However research shows that such vitamins are better absorbed from food sources, rather than from supplements or drinks, said Ms Jasly Koo, a dietitian at KKH.

Vitamins, minerals and phytochemicals in food work hand in hand in the body, she explained.

"When isolated, such as in vitamin water products, they may not provide the same health benefits."

Taking high dosages of vitamins and minerals in the long term can lead to toxicity. Too much vitamin B6, for instance, can cause nerve damage in the limbs.

Sugar is also a concern. A bottle of vitamin water contains an average of five or six tablespoons of sugar, said Ms Koo.

A child aged between three and six should have just three tablespoons of sugar daily, according to the Health Promotion Board.


These drinks are marketed to promote muscle recovery after strenuous exercise. Protein, the key ingredient, stimulates cell proliferation.

This translates to increased muscle growth that improves sporting performance over time, said Dr Ang.


In addition, protein shakes are now also commonly used in weight management. So, they usually contain low-calorie sweeteners and compounds that boost metabolism and aid slimming, said Dr Ang.

Such compounds, which include epigallocatechin gallate and cholorogenic acids, are known to cause side effects such as nausea and insomnia respectively.

In addition, taking extra protein without balancing it with exercise can be harmful. The excessive cell proliferation can increase one's cancer risk over time, said Dr Ang.

Other health risks include kidney damage and obesity. "Normal kids do not really need to drink protein shakes; they can get enough protein from regular meals," he said.

A version of this article appeared in the print edition of The Straits Times on October 13, 2015, with the headline 'Are functional drinks safe for kids?'. Print Edition | Subscribe