Vibrant slush ice drinks linked to health risks

Foto: etorres69 / iStock

Slush ice drinks – also known as a slushy, slushie or slush – is typically served in a cup. Brightly coloured, with a sweet flavour and semi-frozen consistency that resembles melting snow, these drinks are especially popular with children because of the ‘slush’ effect.

Yet the German Federal Institute for Risk Assessment (BfR) and a recent case review in the UK and Ireland warns against possible health risks. Many slush beverages contain glycerol (E422) – a sugar alcohol that can lead to acute and severe symptoms following excessive consumption, particularly in young children.

Foto: bhofack2 / iStock

No comparable cases in Switzerland have been reported to Tox Info Suisse to date. However, the symptoms such as hypoglycaemia, gastrointestinal symptoms, headaches, drowsiness (or even loss of consciousness) are non-specific and, especially on hot days, may not be associated with consuming a slushy.

Case review: Glycerol intoxication following the consumption of slush ice drinks

A case review in the UK and Ireland documented 21 cases of children between the ages of two and seven, who needed emergency treatment soon after drinking a slush ice drink. These cases occurred in the period 2009 to 2024.

Most of the children presented symptoms within an hour of consumption that included hypoglycaemia (95 %), a decrease in consciousness (94 %) and metabolic acidosis (94 %). The children were monitored and treated in hospital, particularly to stabilise their blood sugar levels. All were advised to avoid slushies in future. One seven year old evidently did not abide by this advice and promptly developed the same symptoms after consuming another slushy. High levels of glycerol were found in the urine samples of all the affected children. The authors attributed the symptoms to high quantities of glycerol.

Sugar-free – but not harmless?

Foto: mgstudyo / iStock

The food additive glycerol (also known as glycerine, E422) is used in many sugar-free slush ice products to create the typical semi-frozen consistency, the ‘slush’ effect. Usually this effect is achieved using a large quantity of sugar.

Although the case review covers a period of 15 years, the majority of the documented cases occurred since 2018. It is striking that this rise coincides with the introduction of the sugar tax in the United Kingdom and Ireland in 2018. Since then, the study authors state that manufacturers have evidently increased the use of sugar alcohols such as glycerol as a sugar.

Glycerol in slushies may be problematic

The BfR has analysed 62 samples of slush ice drinks from November 2023 to October 2024. The average glycerol content was approximately 26 g/l with individual samples containing up to 142 g/l.

According to the BfR, it is not possible to make a generalised assessment of the extent of the health risk when consuming a slush ice drink. The concentration of glycerol in the product, the quantity consumed and the body weight of the consumer are the decisive factors. There is no legal maximum quantity for glycerol in foods and the principle of “quantum satis” applies, in other words: as much as is technically needed to achieve the desired result.

For its risk assessment, the BfR used a reference dose of 250 mg glycerol per kg body weight. This equates to the lowest known therapeutic dose, for example as used in hospital as a therapy to reduce intracranial pressure.

Small child, big impact: Even 200 ml can be critical

The analysis shows that for a five-year-old child (20 kg), just 200 ml of a slushy with an average glycerol content can be the equivalent of a dose used in hospital to treat elevated intracranial pressure. A single cup can therefore be problematic for young children.

Foto: foodandstyle / iStock

Summary: A colourful treat with cause for concern

Slush ice drinks look harmless and refreshing at first glance – particularly to children. But these sweet and colourful drinks can have unexpected health implications.

The advice from the British-Irish study is that children younger than eight would be best to avoid slush ice drinks with glycerol. And the advice holds true in this country as well: A firm “no” in front of the slushy stand is less stressful than a visit to the accident and emergency department.

What should you do in an emergency?

Monitor your child shortly after consuming a slushy (containing glycerol) for symptoms such as drowsiness, nausea or confusion,

then:

Give them something sugary (glucose, syrup, banana)
Have your child sit or lay down (they may be at risk of falling!)
For persistent symptoms: Seek medical attention
In case of unconsciousness: Call the emergency services on 144, do not give any liquid

Further information

Glycerol intoxication syndrome in young children, following the consumption of slush ice drinks | Archives of Disease in Childhood – Pubmed

Glycerin in Slush-Ice-Getränken kann unerwünschte gesundheitliche Wirkungen hervorrufen – BfR-Stellungnahme

June 2025