Acute gastroenteritis is a major cause of morbidity and mortality with more than a billion cases worldwide each year. There is a marked geographic disparity in mortality rates, with more than four million deaths each year in developing countries and around 300 deaths (children under 5) each year in the United States.¹

Better mortality in developed countries is attributed to improved economics, sanitation, and access to better medical care. Deaths are mostly due to dehydration, but nutritional status also plays an important role. The American Academy of Pediatrics (AAP) emphasizes that patients at high risk for mortality in the U.S. include infants born prematurely, children of teenage mothers who have not completed high school or who had little or no prenatal care, and mothers who belong to minority groups.

In the U.S., hospitalization and outpatient care for pediatric diarrhea results in direct costs of more than $2 billion, which does not include indirect costs to patient families and their employers.¹ While there have been significant strides in successful treatment of acute gastroenteritis, there is still room for improvement by eliminating preventable deaths and adopting a more cost-effective medical practice, both in the U.S. and abroad.

The medical understanding of appropriate nutritional recommendations in children with acute gastroenteritis has been gradually evolving. The classic BRAT diet (limiting food intake to bananas, rice, applesauce, and toast) has been the standard teaching in the past because the diet was thought to be well tolerated by these patients. Most emergency department discharge instruction sheets contain recommendations for this sort of diet. The goal of this therapy is to reduce the volume and frequency of stool.

Over the past 10 years, however, a consensus has developed that this dietary restriction is a suboptimal choice because it is low in protein, fat, and energy content.² This limited intake is not considered helpful to the body's healing or immune response to infection. The persistence of the BRAT myth is demonstrated by the study design of a recent double-blind randomized clinical trial in which the diet was included as the standard of care for children discharged home with acute gastroenteritis.³

Improper Diet

In the 1950s and 1960s, the discovery that the normal molecular co-transport across gastrointestinal epithelium persists, even in severe diarrhea, led to the development of oral rehydration formulas for children with gastroenteritis. Despite this, empiric observation that “therapeutic starvation” and the BRAT diet decreased stool output encouraged clinicians to encourage “gut rest” followed by diet modification (the BRAT diet) for patients with gastroenteritis.⁴

For many patients with gastroenteritis, the symptoms are the disease, and a reduction in stool volume or vomiting is welcome, even though it may lead to dehydration and compromised recovery. Nonetheless, physician surveys show that these practices continue to be used extensively.^1,5

Another reason physicians may want to limit their patients to a BRAT diet may be fear of inducing lactose intolerance, leading to osmotic diarrhea. Extensive reviews have concluded that most children with acute diarrhea can safely consume undiluted non-human milk during the illness with no prolongation of duration or exacerbation of severity of the diarrhea.⁴

The children who showed signs of intolerance measured by an increase in stool output tended to be those who were severely dehydrated at presentation, those in whom previous treatment had failed, or those who had underlying severe malnutrition. Patients in whom oral rehydration therapy protocols were followed showed no significant problems with subsequent feeding-related lactose intolerance. Milk intolerance can be reduced by mixing the milk with cereal or other foods.⁴

The AAP guidelines for gastroenteritis currently recommend continued feeding of age-appropriate diets, with the only interruption being when and if the patient is undergoing rehydration therapy. They report that this practice does not worsen diarrhea, and may decrease stool output, shorten duration of illness, and improve nutrition. They conclude that as long as children are monitored for signs of intolerance, this regular age-appropriate diet, including full strength milk or cow-milk formula, can be used safely.⁴

Unrestricted Diet

While there is still some controversy about which types of food are optimal for feeding in the spectrum of gastroenteritis presentations, many studies have shown that unrestricted diets do not worsen the course or symptoms of mild diarrhea. For moderate to severe diarrhea, fatty foods and foods high in simple sugars (including sweetened teas, juices, and soft drinks) should be avoided. Appropriate foods include lean meats, yogurts, fruits, and vegetables, as well as complex carbohydrates like rice, wheat, potatoes, bread, and cereals.²

The AAP guidelines recommend oral rehydration therapy (ORT) as a mainstay of therapy in children with acute gastroenteritis complicated by dehydration. ORT requires a patient, persistent provider who is willing to administer repeated small amounts of commercially available rehydration fluids, such as Naturalyte, Pedialyte, Infalyte, Naturalyte, Rehydralyte, or WHO/UNICEF oral rehydration salts. Apple juice, soda, and sport drinks are not appropriate for replacing gastrointestinal fluid losses because their carbohydrate concentration is too great and the electrolyte concentrations are too small.

In cases where dehydration worsens despite oral therapy, IV rehydration is the more rapid and reliable method. Depending on the severity of dehydration, the AAP recommends continued feeding or early reintroduction of age-appropriate feeding. Again, however, recent surveys of American physicians show that few follow published guidelines even when the dehydration has resolved. Common deviations from these guidelines include extended rehydration up to 24 hours, frequent use of lactose-free formulas such as soy-based formulas, and delay in the introduction of feedings until the diarrhea stops.¹

Unnecessarily withholding nutrition during the acute phase of illness can be counterproductive. Only a short interruption in feeding is warranted while undergoing rehydration therapy in patients with moderate to severe dehydration. In patients who do not require IV fluids or hospitalization, adequate oral rehydration can be accomplished within four to six hours.

In the ED, a common pitfall is to provide overly aggressive ORT to a thirsty child, which may induce vomiting and delay the rehydration process. Once the rehydration process is complete, there is no reason to delay feeding, hence the AAP's emphasis on early reintroduction of age-appropriate feeding. The idea of limiting the nutritional content of these feedings to the BRAT diet is no longer recommended.

Axioms in Emergency Medicine is written specifically for emergency medicine residents to dispel myths and misconceptions about different clinical entities. The column is written each month by a resident from the Emergency Medicine Residency Program at Drexel University College of Medicine in Philadelphia.