Young kids can become seriously ill after drinking sugar-free slushies containing glycerol, a sugar alcohol used to help maintain the drinks’ icy texture, a new study warns.

Children 7 and younger suffered a sudden sharp drop in blood sugar, reduced consciousness and a build-up of acid in their blood within an hour of downing slushies containing glycerol, researchers reported March 11 in the journal Archives of Disease in Childhood.

This “glycerol intoxication syndrome” from sugar-free slushies affected 21 children in the U.K. and Ireland, sickening all but one between 2018 and 2024, researchers said.

“Healthcare professionals and parents should be aware that young children can become seriously unwell due to glycerol intoxication, shortly after consuming slush ice drinks containing glycerol,” concluded the research team led by senior investigator Ellen Crushell, a metabolic disease consultant with Children’s Health Ireland.

Glycerol is a sugar substitute that is sometimes added to foods like protein bars and shakes, diet foods, dried fruits, chewing gum, cake icings and sugar-free candy, according to the International Food Information Council.

Slushies rely on heavy doses of sugar to keep the ice from fully freezing, Crushell said. Many sugar-free slushies maintain that texture by substituting sugar with glycerol.

U.S. slushy brands use glycerol out of concern for excess sugar in children’s diets. U.K. and Ireland have instituted a “sugar tax” on sugary beverages, leading to the use of glycerol in slushies, the paper also noted.

“Slush ice drinks have contained a lot of glycerol instead of sugar in recent years due to the increased demand for sugar-free food,” Crushell told ABC News. “To maintain the slush, you need either sugar or glycerol, but due to public health concerns and a sugar tax, sugar was reduced and glycerol was added.”

Many of the children fell ill within an hour of drinking a sugar-free slushy, with most either unconscious or semi-conscious by the time they reached a hospital, the paper says. One of the children suffered a seizure.

About 20 children suffered from hypoglycemia, and in 13 cases their blood sugar was so low they were diagnosed with severe hypoglycemia, the report says.

The children included in the new paper became so sick from hypoglycemia that they were referred from the ER to specialists to see if they suffered from a metabolic disorder like diabetes, researchers said.

All of the children recovered quickly after their blood sugar levels were stabilized, researchers said.

Parents were advised to not give their kids any more sugar-free slushies, researchers said. Most followed this advice, and their kids had no further episodes of hypoglycemia.

But in one instance, a 7-year-old suffered from vomiting and drowsiness after drinking another sugar-free slushy, researchers said.

Recognizing the symptoms from their child’s previous brush with a slushy, the parents gave the child a sugary beverage and called an ambulance. By the time paramedics arrived, the child’s blood sugar levels were back to normal and their symptoms were already fading, researchers said.

Based on some of these cases, the U.K. Food Standards Agency and the Food Safety Authority of Ireland have already recommended that children 4 and younger shouldn’t be given any slushies containing glycerol, and kids 10 or younger should not have more than one, the paper noted.

Researchers warned these recommendations may no longer be enough.

“There is poor transparency around slush ice drink glycerol concentration; estimating a safe dose is therefore not easy,” the researchers 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.”

Young kids might be more vulnerable to glycerol’s effects because their smaller bodies and developing metabolism aren’t able to process the sugar alcohol efficiently, researchers said.

U.K. and Irish food regulators “suggested that 125 mg/kg of body weight per hour is the lowest dose that is associated with negative health effects,” researchers noted.

“For a toddler this may equate to 50–220 ml (1.7-7.4 oz.) of a slush ice drink. The standard size drink sold in the UK and Ireland is 500 ml (17 oz.),” more than double, they point out.

Glycerol is approved by the U.S. Food and Drug Administration for use as a food additive in the United States, according to the American Chemistry Council.

More information

The American Chemistry Council has more on glycerol.

SOURCES: BMJ, news release, March 11, 2025; Archives of Disease in Childhood, March 11, 2025; ABC News, March 12, 2025

Source: HealthDay

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