Diarrheal diseases are the third leading cause of mortality in the world, with nearly 2 million deaths annually among children under age 5 years. Several clinical trials of oral zinc supplementation performed in developing country populations have confirmed this nutrient's efficacy in reducing the severity and frequency of diarrhea. The World Health Organization (WHO) has recommended global use of zinc supplementation in all children with diarrhea despite little or no data from trials in industrialized/developed settings. In the United States over 4 million children suffer annually from diarrheal illness. Although mortality is not a significant factor in U.S. cases, 75% of all cases present to medical care resulting in over 200,000 hospitalizations annually for diarrhea. This has significant impact on U.S. healthcare costs, with an average of $391 per outpatient treatment and $2,549 per inpatient treatment spent on each episode of acute diarrheal illness. The goal of this study is to evaluate the effectiveness of oral zinc in decreasing the duration of diarrhea in children treated as outpatients and in decreasing the duration of hospitalization in children treated as inpatients in an industrialized country. The results of this study promise to have a substantial impact on the management of a common pediatric health problem, and could conceivably affect direct and indirect healthcare costs to society.

In developing countries, diarrheal diseases are a leading cause of childhood morbidity and mortality. In the United States an estimated 4.67 million children per year suffer from gastroenteritis with a diarrheal component, impacting the delivery and cost of healthcare. Seventy-five percent of these children are brought to physician care across a range of settings from clinics to emergency departments. Children less than five years of age average 1.3 - 2.5 episodes per year, with 1.4% of those children requiring hospitalization annually. This results in an estimated 209,000 hospitalizations yearly for gastroenteritis. The impact of acute gastrointestinal disease can be felt in the developed world, including the United States, as cost attributed to hospitalization and productivity lost. Attempts at treating gastroenteritis have included Oral Rehydration Solution (ORS), introduced 30 years ago by the WHO, which continues to provide a safe and effective way to maintain hydration during acute illness. ORS, however, does not reduce the volume or frequency of stool output in diarrhea. The anti-diarrheal medication loperamide (Imodium®) was commonly used in children until reports of serious adverse reactions caused its use to fall out of favor. There are no other medications or supplements available to specifically treat the diarrheal component of gastroenteritis and studies have shown that adherence to treatment recommendations regarding fluid therapy is poor because care givers want to reduce duration of illness as opposed to supporting children through the natural course of the disease. The desire to relieve diarrheal symptoms often leads care givers to seek antibiotics during a time of rising antibiotic resistance, as well as other treatments with no proven efficacy.

Zinc is an essential trace element for humans. Its physiologic roles are seen throughout the body as a critical cofactor for enzymatic reactions; most notable are its actions in the gastrointestinal (GI) tract. Zinc is an important component of brush border enzymatic activity which promotes gastrointestinal absorption, it regulates water/electrolyte transport at the cellular level, and it enhances the repair of the intestinal mucosa by bolstering immune function. Over the past 10-15 years, there have been more than a dozen randomized controlled trials of zinc supplementation performed in children living in developing countries that have reported improvements in the duration and severity of diarrhea when compared to placebo in a variety of in- and outpatient settings. The majority of zinc trials were conducted in countries at high risk of zinc deficiency, but those conducted at medium risk showed similar effect on duration and severity. When stratified across all nutritional groups based on serum zinc levels a significant effect was seen compared to placebo despite baseline zinc level, with no occurrence of serious adverse reaction in any group. Given these results, the WHO has endorsed zinc supplementation for all children with acute diarrhea, despite the lack of data from similarly designed studies in industrialized/developed settings.

Inclusion Criteria:

• Healthy Children with non-bloody diarrhea illness defined as loose or watery stools
• Symptoms must be present for greater than 24 hours but less than 72 hours.
• Comorbid conditions including; Asthma, Gastroesophageal reflux (unless followed by a Gastroenterologist), Mild speech, language, motor delays, Benign heart murmurs, Isolated atrial septal defect (ASD) or ventricular septal defect (VSD), Epilepsy (unless developmentally delayed), Children born Prematurely between 33-37 weeks without long term sequelae, Repaired tetralogy of fallot (no cardiac issues for >6 months), Diabetes may be enrolled in the study.

Exclusion Criteria:

• Children with symptoms less than 24 hours
• Children with symptoms greater than 24 hours
• Failure to thrive
• G or J tube
• Major surgery within last 3 months
• Minor surgery (tonsillectomy, ear tubes, skin lesion removals etc) within last 1 month
• Followed by GI service for any reason (crohns, ulcerative colitis, constipation)
• Developmental delay, patient >1 year behind milestones
• Current brain tumor
• Currently being treated for cancer or in remission < 6 months
• Intussuception
• Antibiotics in the last 14 days or currently taking antibiotics for any reason
• Autism
• Children born premature <33 weeks
• Cystic Fibrosis
• Major congenital Heart Disease (any disease where child's baseline oxygen saturations <93%)
• Short Gut
• Liver disease
• History of bowel resection

Overall low number of inpatients with diarrhea meeting the study enrollment criteria of being otherwise healthy

Data on adverse events were collected for each patient for their 28 day study period. The trial was conducted from November 1 2010 to May 25 2014. The primary completion date of the trial was May 15th 2014 and the study completion date was May 25th 2014.