Acute gastroenteritis is an important cause of childhood morbidity and mortality worldwide. After the introduction of oral rehydration therapy to correct water and electrolyte losses caused by vomiting and diarrhea, mortality was significantly reduced (1,2). In 1992 the European Society of Paediatric Gastroenterology and Nutrition (ESPGAN) recommended that oral rehydration solution (ORS) for children in Europe should have an osmolality between 200 and 250 mOsm/l. Glucose concentration should be between 74 and 111 mmol/l and ORS should contain 60 mmol/l and 20 mmol/l of sodium and potassium, respectively. This recommendation differed from that of the World Health Organization (WHO) in that the WHO recommended ORS with a maximal osmolality of 311 mOsm/kg and a sodium content of 90 mmol/l. However, several studies have shown that lowering sodium and glucose concentration in ORS significantly reduced stool output, vomiting and the need for intravenous therapy (3). Because of its salty taste, mild to moderately dehydrated children sometimes refuse to drink ORS. To prevent admission to the hospital, ORS is often flavored with different kinds of juices to improve palatability. It has been shown that flavoring alters electrolyte content and osmolality (4), thus reducing its efficacy. Whether flavoring of ORS actually improved palatability, however, was not investigated.
In this study we investigated the biochemical changes of flavoring ORS with apple juice, orange juice or orangeade in various concentrations. We then compared the palatability of two oral rehydration solutions flavored with either apple juice or orange juice and a commercially available ORS flavored with peach.
MATERIALS AND METHODS
Five commercially available oral rehydration solutions were used in the study (Table 1); only one was flavored. To the unflavored solutions commercially available apple juice, orange juice or orangeade were added. In Table 2 the chemical compositions of apple juice, orange juice and orangeade are shown. The ORS/fruit juice or ORS/orangeade solutions were made in ratios of 4:1 (80 ml ORS combined with 20 ml juice), 3:1 (75 ml ORS combined with 25 ml juice) and 1:1 (50 ml ORS combined with 50 ml juice). Osmolality, sodium, potassium and glucose content of these solutions were analyzed. Chloride concentration was measured on a Chloride analyzer 925 (Ciba Corning, Medfield, MA). Sodium and potassium were analysed using flame emission spectrophotometry on a 943 Flame Photometre (Instrumentatin Laboratory, Milano, Italy). Glucose was determined using an Ebio 6666 glucose analyzer (Eppendorf, Hamburg, Germany) and osmolality using an Osmomat 030 osmometer (Gonotec, Berlin, Germany).
Palatability of the 4:1 ORS/apple juice and ORS/orange juice solutions (80 ml ORS combined with 20 ml juice) and the commercially flavored ORS were then assessed in 30 blinded persons (adults and children) who visited the pediatric outpatient department of the Maxima Medical Center in Veldhoven, the Netherlands. None of these persons suffered from gastroenteritis and as the solutions were offered in identical containers, none of the test persons were aware which solution they drank. Each person was asked to grade the solutions as "good," "not good" or "very bad."
All additions (apple juice, orange juice or orangeade) to ORS caused a decrease of sodium (−30 to −53 mmol/L) and chloride concentration (−27 to −47 mmol/L). Potassium concentration increased (3 to 13 mmol/L) except when ORS was flavored with orangeade (reduction, −7.0 to −2 mmol/L). The results are shown in Figure 1. Osmolality increased to unacceptable levels, especially when orangeade was used for flavoring, because of the increased glucose concentrations of the solutions after flavoring (Table 2). None of the solutions made fulfilled the WHO criteria for ORS (maximal osmolality, 311 mOsm/kg; potassium, 20 mOsm/L; sodium, 90 mOsm/L and chloride, 80 mOsm/L). The ORS solution flavored with apple juice and orange juice in the ratio of 4:1 (80 ml ORS combined with 20 ml juice) approached the WHO recommendation and was therefore used to assess palatability compared with commercially flavored ORS. Palatability results as judged by adults and children were similar and therefore pooled. The commercially flavored ORS was judged as most palatable (Fig. 2). Its composition fulfills the criteria of ORS by ESPGAN.
Oral rehydration therapy is, according to the ESPGAN, one of the nine pillars on which the treatment of dehydration caused by acute gastroenteritis is based (5). Although severely dehydrated children rarely refuse to drink ORS, mild to moderately dehydrated children sometimes do. Parents and physicians therefore tend to flavor ORS with juice or orangeade. In a previous study, it was shown that flavoring ORS causes severe alterations of electrolyte content and osmolality (4). In an animal model it was furthermore shown that when glucose was replaced by sucrose and chloride by citrate to improve palatability, salt and water absorption was decreased (6). Despite these findings, none of the recently published guidelines for the management of acute diarrhea advised against flavoring ORS (5,7,8). The ESPGAN recommends that ORS for children in Europe should have an osmolality between 200 and 250 mOsm/l. Glucose concentration should be between 74 and 111 mmol/l glucose and it should contain 60 mmol/l and 20 mmol/l of sodium and potassium, respectively. The WHO recommends a maximal osmolality of 311 mOsm/l and a sodium content of 90 mmol/l (3,5,9). Our study confirms earlier findings that flavoring increased osmolality to greater than 311 mosm/kg in all cases and decreased sodium concentration below 60 mmol/L in most cases. Only when ORS was flavored in a ratio of 4:1 (80 ml ORS combined with 20 ml juice) with apple or orange juice did the solution approach the WHO recommendations. The study also shows that flavoring ORS with either apple juice or orange juice fails to improve palatability compared with commercially flavored ORS, which fulfills ESPGAN criteria. Non-dehydrated children were quite willing to drink a small amount of the latter but not of ORS flavored with juice. Whether this applies to dehydrated children is currently under investigation.
Despite the limitations of this study, we strongly advise against flavoring ORS, as it causes severe alterations of electrolyte concentration and osmolality and palatability does not improve compared with commercially flavored ORS.
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