Researchers are advising that children under the age of eight should not consume slush ice drinks that contain the sweetener glycerol, following a study that linked the substance to a condition known as "glycerol intoxication syndrome". This syndrome has been associated with symptoms such as reduced consciousness and low blood sugar levels in some children.
Glycerol, which is both a natural alcohol and a sugar substitute, is used in slush drinks to help maintain their semi-frozen texture by preventing the liquid from freezing completely. In the UK, current guidelines advise against giving slushies containing glycerol to children under four years old, but experts are now suggesting that this public health advice needs to be re-evaluated.
The call for review comes after a study published in the Archives of Disease in Childhood, where researchers from University College Dublin examined the health records of 21 children from the UK and Ireland who became ill after consuming a slushie. These cases occurred between 2018 and 2024, involving children aged between two and nearly seven years old.
The children were initially treated for hypoglycaemia, or low blood sugar, upon presenting at emergency departments.
The study indicates that drinking slushies with glycerol "may cause a clinical syndrome of glycerol intoxication in young children", leading to symptoms such as decreased consciousness, hypoglycaemia, lactic acidosis (an excess of lactic acid in the body), and hypokalaemia (low potassium levels).
They further stated: "Clinicians and parents should be alert to the phenomenon, and public health bodies should ensure clear messaging regarding the fact that younger children, especially those under eight years of age, should avoid slush ice drinks containing glycerol."
The Food Standards Agency (FSA) advises against children under four consuming slush ice drinks containing glycerol. It also suggests limiting consumption to no more than one slush per day for children aged between five and 10 years.
According to the review, the time between drinking the slushie and becoming ill was known for 15 children, with 14 becoming unwell within an hour. All 21 children recovered quickly and were discharged with advice not to drink slushies, according to the study.
Out of the group, 20 children adhered to this advice and experienced no further episodes of low blood sugar. However, one child consumed another slushie at the age of seven and developed symptoms within an hour.
Researchers commented: "There is poor transparency around slush ice drink glycerol concentration; estimating a safe dose is therefore not easy."
They also suggested that the speed and dose of ingestion, along with other factors such as whether the drink is consumed alongside a meal or during a fasting state, or consumed after high-intensity exercise, may contribute to the issue.
They concluded by stating that "there are no nutritional or health benefits from these drinks" and "they are not recommended as part of a balanced diet".
According to the academics, "Recommendations on their safe consumption therefore need to be weighted towards safety,".
They added: "To ensure safe population-level recommendations can be easily interpreted at the individual parental level, and given the variability across an age cohort of weight, we suggest that recommendations should be based on weight rather than age."
They also suggested: "Alternatively, the recommended age threshold may need to be higher (eight years), to ensure the dose per weight would not be exceeded given normal population variation in weight."
