Experts have issued an alarming health warning over the hidden dangers of a little-known additive in a popular children’s drink. 

Called glycerol, the super-sweet substance is a common ingredient in ‘slushies’ — bright, colourful ice cold drinks that are a mainstay at cinemas and corner shops.

But in updated advice, the Food Standards Agency (FSA) has now warned that slush ice drinks containing glycerol are not suitable for children under seven. 

It comes as amid a surge in horrifying reports of children collapsing after consuming the drinks. 

One two-year-old girl was left ’20 minutes from death’ after having a slushy drink at her friend’s birthday party, according to her grandmother.

Experts said just one 350ml drink, about as much as can of Coca Cola, could be enough to cause problems in children under four. 

In youngsters aged five to ten, one and a half of these drinks can have dangerous effects, if consumed quickly. 

In March, doctors also blamed slushies for a spate of 21 hospitalisations in children who needed medical care within an hour of consuming the drinks.

Arla Agnew (pictured) was left ’20 minutes from death’ after consuming a slushy drink at her friend’s birthday party, according to her grandmother

Her grandmother, Stacey Agnew said she knew something awry with the toddler, and was left terrified when she suddenly appeared lifeless

The updated FSA advice applies to ready-to-drink slush ice drinks with glycerol in pouches and home kits containing glycerol slush concentrates. 

Glycerol, also called E422 or glycerine on some labels, is a naturally occurring alcohol and sugar substitute which is added to slushies to prevent them from freezing.

Once ingested the substance is known to absorb a great deal of water and sugar from the bloodstream, before being broken down by the liver and kidneys. 

It’s this sudden loss of internal moisture and blood sugar that experts believe leads to the serious and potentially life-threatening reaction in younger children.

Professor Susan Jebb, FSA Chair, said: ‘In the warm weather, children may be more likely to consume slush ice drinks containing glycerol, so it’s important that parents and carers are aware of the risks. 

‘As a precaution, the FSA is recommending that children under seven do not consume slush ice drinks containing glycerol. 

‘With our counterparts in Scotland, we will be talking to parent groups and charities to provide updated guidance that is useful and applicable across the UK.’

She added: ‘We expect industry to share data on the quantity of glycerol in their products to inform our future work. 

Roxy Wallis feared she would have to take her sons Austin (back) and Ted (front) to hospital after they suddenly fell ill and lethargic after consuming popular slushy drinks

She said the normally ‘bubbly’ pair became sickened within mere minutes of consuming the drinks

‘Meanwhile, there are immediate actions they can take that can help protect children and reduce the risk from these products. 

‘For example, retailers should limit cup sizes and should not offer free refill promotions to children under 10.’

Gavin Partington, Director General of the British Soft Drinks Association, said: “We welcome this updated advice from the Food Standards Agency on the consumption of slush ice drinks containing glycerol. 

‘As is standard practice, we will work with the FSA to provide Industry information about its use.

‘It’s worth noting that glycerol is authorised as an additive for use in the UK and Europe and has been used for many years by manufacturers of “slush” ice drinks as a replacement for sugar in order to stop the product from freezing. 

‘Our members abide by all relevant and current ingredient legislation, including on glycerol. 

‘We support the FSA’s efforts to ensure parents have the right information to safeguard their children.’

It comes as one grandmother last year told how her granddaughter was left ’20 minutes from death’ after consuming a slushy drink at her friend’s birthday party.

FSA chiefs based their recommendations on a 350ml-sized drink, similar to ones available in shops and cinemas across the UK

Arla Agnew became ‘grey’ and fell unconscious only half an hour after sipping half of the drink at the event on Saturday.

Stacey Agnew said she knew something awry with the toddler, and was left terrified when she suddenly appeared lifeless.

After rushing the tot to Gollaway Community Hospital, medics determined the child had gone into hypoglycemic shock – and the ice drink may have been to blame.

But the case was just one in a wave of young children being sickened after consuming slushies.

Earlier this year in March, a terrified mother also warned of the dangers of popular slushy drinks after her two, young sons suffered what appeared to be a dangerous reaction to the beverages.

Roxy Wallis, from Cambridgeshire, was shocked to find her sons vomiting, deathly pale and looking ‘lifeless’ minutes after consuming just 300ml of the drinks, equivalent to less than a can of Coke. 

The 36-year-old believes they suffered from glycerol toxicity — dangerously low blood sugar triggered by iced artificially sweetened slushies.

In the same month, another mother also shared how her four-year-old was left ‘floppy and unconscious’ and rushed to hospital after consuming a drink at a children’s play centre. 

Four year-old Marnie Moore spent three days in hospital after consuming a 500ml slushy drink

Kim Moore bought the slushy drinks for both her daughters: Marnie, four and Orla, six

Marnie Moore, from Lancashire, was rushed to hospital where she received urgent treatment for glycerol toxicity.

Her mother, Kim Moore, 35, is now calling for a ban on the drinks for under 12s.

‘If I hadn’t taken her to hospital, it may have had a different outcome,’ she said.

‘So many places promote free slushies when you play there but you’re promoting poison.

‘I don’t think they should be sold to kids 12 and under. And I personally wouldn’t allow my child to drink one at all. It’s not a risk I’m willing to take.’

Slushies were traditionally made with a sugar solution to prevent the liquid ingredients from fully freezing, at about 12g of sugar per 100ml.

But formulas using glycerol only need 5g per 100ml to achieve the same result.

Authorities have previously warned that just one 350ml drink containing the equivalent of about 17.5g, (about three teaspoons) of glycerol, could theoretically tip under-fours over the ‘safe’ threshold.

But experts warn older children can also be at risk of glycerol intoxication from consuming multiple E422-laden drinks in quick succession. 

According to regulator the Food Standards Agency most slushies contain around 16g of glycerol.

However, there is no maximum amount of glycerol that manufacturers have to legally adhere to.

Most brands don’t state how much glycerol is in each slushy.

Some brands have already removed glycerol from their recipes in response to the concerns about the ingredient, with Slush Puppie being one of them.