Are functional drinks safe for kids?

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.

Sports drinks

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.

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.

Energy drinks

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.

Vitamin water

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.

Protein shakes

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.

chpoon@sph.com.sg


This article was first published on October 13, 2015.
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