How much caffeine is safe for kids?

Health experts warn that younger people have a lower threshold against the effects of caffeine than adults. Photos / Supplied

They may not be sipping flat whites like their parents, but children are consuming more caffeine than ever before, and health organisations are questioning how much is too much.

Caffeine, which sources include coffee, energy drinks, some teas and soft drinks, is the most available and widely-used psychoactive substance in the world. It's the only drug legally accessible and socially acceptable for children and teenagers to take, and as kids and teens increasingly reach for the fizzy drink, caffeine levels among this age group are skyrocketing.

While small amounts are harmless, health experts warn that younger people have a lower threshold against the effects of caffeine than adults, and too much can prevent young people from getting the sleep and nutrients they need for healthy physical development.

So how much is safe?

The UK Food Standards Agency says children and adolescents should limit themselves to no more than 100mg a day. Adults can safely consume up to 400mg of caffeine a day - the equivalent of about four cups of coffee or two energy drinks.

Pregnant and breastfeeding women should not have more than 200mg of caffeine during the day - roughly two mugs of instant coffee, or one filter coffee.

In New Zealand, the Ministry of Health recommends children under 12 stay away from energy drinks, which can cause a rapid caffeine spike in the body, unlike other foods with comparatively smaller amounts, such as chocolate.

How much caffeine is really in your drink? Image / Supplied

And when it comes to loading up on caffeine, some of the more popular sources pack a bigger punch than others.

A can of Coca-Cola has 32mg, while than same amount of Diet Coke comes in slightly higher at 42mg. A can of Red Bull has 80mg, but some energy drinks contain as much as 500mg of caffeine per can.

Other popular fizzy drinks such as Monster contains 160mg per 450g while Mountain Dew has 54mg per can.

According to British health statistics, school-age children are the fastest-growing population of caffeine users. The finding has prompted health organisations to call for awareness programmes to educate young people on the potential dangers of the substance.

How it works

Caffeine is absorbed very quickly into the body and then passes into the central nervous system. The popular stimulant can decrease a child's ability to perform tasks involving delicate muscular coordination, arithmetic skills or accurate timing, and some experts say the substance should not be given to children under 12.

In low doses, caffeine can affect the body causing decreased appetite, increased urination, hyperactive behaviour and difficulty sleeping.

Higher amounts of the stimulant can trigger nausea, vomiting, muscle cramps, twitching and agitation when a child consumes more than 4.5 mg per pound of body weight.

Severe caffeine toxicity can lead to fits, an increased heart rate, irregular heart beat and palpitations.

- nzherald.co.nz