Chemical analysis of cool drinks and pure fruit juices--some clinical implications.

The pH of cool drinks and fruit juices is very low and ranges from 2,4 (Pepsi Cola) to 3,7 (fresh orange juice). The osmotic concentration of most cool drinks and fruit juices is considerably higher than that of blood and, with the exception of Isotonic Game, ranges from 430 mOsm/kg (Coca Cola) to 1 297 mOsm/kg (Liquifruit Grape). Glucose, fructose and sucrose contribute from 72% to 98% of the osmotically active particles in cool drinks and fruit juices and their high carbohydrate content causes concern about substrates for oral bacteria to produce acid as well as daily energy intake. The sodium (Na), potassium (K), calcium (Ca) and phosphorus (P) content of cool drinks is low although K and P may contribute significantly to dietary intake when most fruit juices are consumed. K is virtually absent in Coca Cola and its use in replacing lost minerals, e.g. in infantile gastro-enteritis, is disputed. The relatively high levels of K and P in fruit juices could be harmful to patients suffering from chronic uraemia. The selected cool drinks and fruit juices analysed contain very little Na and should not pose problems to hypertensive patients.