Zinc Supplementation for Diarrhea: Indications and Duration
Zinc supplementation should be given for 10-14 days in children with acute diarrhea, specifically targeting those aged 6 months to 5 years in zinc-deficient populations or with signs of malnutrition, using 20 mg elemental zinc daily (10 mg for infants under 6 months). 1, 2
Who Should Receive Zinc
Children 6 Months to 5 Years
- Zinc is strongly recommended for children in this age group who reside in countries with high zinc deficiency prevalence or show signs of malnutrition. 1, 2
- The Infectious Diseases Society of America provides strong recommendation with moderate evidence that zinc reduces diarrhea duration by approximately 10-27 hours in malnourished children from zinc-deficient regions. 1, 2
- Zinc should NOT be used as a substitute for oral rehydration therapy—rehydration remains the cornerstone of management. 1
Infants Under 6 Months
- Zinc supplementation is NOT routine for healthy infants under 6 months except in zinc-deficient populations or documented zinc deficiency. 1
- When indicated, use 10 mg elemental zinc daily for 10-14 days. 1, 2
Adults
- There is no high-quality evidence supporting zinc supplementation for adults with diarrhea. 2
- Empiric antimicrobial therapy is not recommended for most adults with acute watery diarrhea without recent international travel. 3
Dosing Protocol
Standard Dosing
- Children 6 months to 5 years: 20 mg elemental zinc daily for 10-14 days 1, 2
- Infants under 6 months (in zinc-deficient populations): 10 mg elemental zinc daily for 10-14 days 1, 2
Duration Rationale
- The 10-14 day duration is critical because zinc supplementation continues to prevent further diarrheal episodes for up to 2-3 months after treatment. 4
- Stopping early eliminates this preventive benefit.
Clinical Evidence Supporting Use
Efficacy Data
- Pooled analysis of randomized controlled trials shows zinc-supplemented children have a 15% lower probability of continuing diarrhea on any given day in acute diarrhea, and 24% lower probability in persistent diarrhea. 5
- In malnourished children, zinc reduces diarrhea duration from 103 hours to 70 hours, decreases stool output, and reduces ORS consumption. 6
- Zinc reduces the proportion of diarrheal episodes lasting ≥7 days (odds ratio 0.09). 7
Mechanism of Benefit
- Zinc deficiency is prevalent in children in developing countries, and supplementation provides therapeutic benefits beyond simple replacement. 5
- The effect is independent of viral enteropathogens in stool. 8
Critical Pitfalls to Avoid
Never Substitute for Rehydration
- Zinc must be given alongside—never instead of—oral rehydration therapy. 1, 2
- Reduced osmolarity ORS remains first-line therapy for mild to moderate dehydration. 3
Avoid in Well-Nourished Populations
- Do not use zinc in well-nourished children from developed countries where benefit is unproven. 2
- The evidence base comes primarily from zinc-deficient populations in developing countries. 5, 8
Vomiting Risk
- Zinc supplementation is associated with higher risk of vomiting, which can be mitigated by using lower doses or dividing doses throughout the day. 2
Integration with Overall Diarrhea Management
Treatment Algorithm
- Assess and correct dehydration with ORS or IV fluids based on severity 3, 2
- Continue breastfeeding on demand without interruption 9
- Add zinc supplementation if child is 6 months to 5 years AND lives in zinc-deficient region or shows malnutrition 1, 2
- Resume age-appropriate feeding immediately after rehydration 9
- Replace ongoing losses with 10 mL/kg ORS per liquid stool 9