It is commonly believed that ‘flat’ carbonated drinks are an effective alternative to oral rehydration solutions, particularly for children who do not like their taste, according to researchers at the children’s emergency department at Watford General Hospital.
However, they were unable to find any published trials to back this up and, instead, compared information about the contents of different types of liquids.
World Health Organisation recommendations are for oral rehydration solution to contain 75mmol/l of sodium and the same amount of glucose. But the authors found carbonated drinks had much lower levels of sodium (1.0–9.9 mmol/l) and potassium (0–0.3 mmol/l), but much higher levels of glucose.
‘Carbonated drinks, “flat” or otherwise, including cola, provide inadequate fluid and electrolyte replacement and cannot be recommended,’ they said in the online version of Archives of Disease in Childhood.