Experts warn that children under eight should not drink slushies containing glycerol amid concerns over their health. Glycerol is a naturally occurring alcohol and sugar substitute that helps slushies maintain their texture by preventing liquid from freezing solid. It is currently an EU-approved additive.

However, brightly colored drinks can cause “glycerol intoxication syndrome” in young children, a condition that causes headaches, nausea and vomiting, and, in severe cases, loss of consciousness and low blood sugar (hypoglycemia).

The review team at University College Dublin, led by the consultant pediatrician Prof Ellen Crushell, has called for health advice to be revised following the research.

Warnings over icy drinks

Experts at Children’s Health Ireland Temple Street and the UCD School of Medicine have urged parents not to give children aged under eight the icy drinks after examining the cases of 21 children across the UK and Ireland who became sick soon after drinking the beverages.

“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 study states.

The research team did not know precisely how much glycerol is in a regular 500ml slushie, and there is currently no requirement to label the amount used.

Consultant metabolic pediatrician Professor Ellen Crushell, who led the study, says: “If a young child takes a large dose of glycerol, such as you might find in a slushie, that’s absorbed straight away into the system, and that big dose of glycerol, the metabolism of a small child can’t really cope with it. It interferes with their glucose metabolism, and that’s how your body keeps your blood sugar normal.”

“What’s needed is more transparency around glycerol because, at the moment, it doesn’t need to be declared or measured. Its use is becoming more ubiquitous as we need less sugar in our diets.”

Slushie symptoms

The study occurred between 2018 and 2024, with children between two and almost seven years old. In each case examined the child became “acutely unwell with a series of shared symptoms soon after drinking a slushie.” These symptoms included headaches, nausea, and vomiting, followed by reduced consciousness’ referred to as drowsiness or coma, and very low blood sugar levels with high lactic acid levels. Glycerol was also found in their urine.

The findings have been published in the British Medical Journal’s Archives of Disease in Childhood. 

Parents are advised to limit young children’s consumption of slushies that contain glycerol due to potentially negative side effects, including headaches, nausea, and vomiting. Older children and adults should have no more than one a day.

However, the Food Safety Authority of Ireland’s guidance could go further, according to Professor Crushell.

“To be safe and to account for normal variations in children’s weights, the guidance not to consume could potentially be extended to children under eight years of age.”

“It should also be noted that all slush ice drinks, whether containing sugar or glycerol, convey no health benefits and are not part of a healthy diet for children of any age,” adds Dr. Abigail Collins, National Clinical Lead for the HSE’s Child Health Public Health Programme.