Slush ice drinks containing glycerol, popularly called slushies, are harmful to children under eight years of age, doctors warn in a new study after a string of hospitalisations in the US and the UK.
New research, published in the journal Archives of Disease in Childhood, reviewed the medical cases of 21 children who became acutely unwell shortly after drinking one of these products.
The children in the study became unwell with a cluster of symptoms, which the researchers refer to as glycerol intoxication syndrome.
These symptoms included reduced consciousness, a sudden sharp drop in blood sugar, and a build-up of acid in the blood, indicating a kind of poisoning or metabolic disorder.
Brightly coloured slush ice drinks are widely sold, particularly targeting children.
While their ingredients typically vary, in the UK and Ireland these drinks are sold as “sugar free” products or with “no added sugar”, and instead contain glycerol (E422, also known as glycerin).
Glycerol is added to prevent the drinks from fully freezing and maintaining a slush effect in the absence of a high sugar content.
The medical notes of 21 children reviewed in the study reveal that they were initially diagnosed with hypoglycaemia after arrival in emergency care, and apart from one child, all others were referred for further review between 2018 and 2024.
Scientists found that the children on average were 3 and a half years old, but their ages ranged from 2 to nearly 7.
Fourteen of the 21 children quickly became ill after consuming a slush drink “within 60 minutes” and, 16 of them experienced a significant and sudden reduction in consciousness, researchers say.
The kids recovered quickly after initial resuscitation and stabilisation of their blood glucose, the study noted.
Nearly all but one of the children avoided slush ice drinks after their respective incidents and experienced no further episodes of hypoglycaemia, researchers say.
But one of them, again had another slush ice drink at the age of 7 and developed symptoms within an hour, doctors say.
The child’s parents gave the kid a glucose drink and called an ambulance, and the blood glucose was back to normal levels before paramedics arrived, they say.
Following some of these cases, the UK Food Standards Agency recommends that young children – 4 and under – shouldn’t be given slush ice drinks containing glycerol and that those aged 10 or younger should not have more than one.
Researchers caution that this recommended age threshold needs to be increased to 8 years to ensure the dose per weight would not be exceeded due to normal population variation in weight.
“There is poor transparency around slush ice drink glycerol concentration; estimating a safe dose is therefore not easy,” scientists wrote.
“It is also likely that speed and dose of ingestion, along with other aspects, such as whether the drink is consumed alongside a meal or during a fasting state, or consumed after high-intensity exercise, may be contributing factors,” they added.
