Zinc for Nausea in Gastrointestinal Infections
Zinc supplementation does not specifically reduce nausea in adults or older children with acute gastrointestinal infections, and the available evidence focuses on diarrhea reduction in young children rather than nausea control.
Evidence for Zinc in Gastrointestinal Infections
The current guideline recommendations and research evidence address zinc's role in treating diarrhea, not nausea specifically:
For Children (6 months to 5 years)
- Zinc supplementation is strongly recommended for children aged 6 months to 5 years with acute diarrhea who reside in countries with high zinc deficiency prevalence or show signs of malnutrition, at a dose of 20 mg elemental zinc daily for 10-14 days 1, 2, 3.
- This reduces diarrhea duration by approximately 10-27 hours in zinc-deficient or malnourished populations 2, 4.
- The benefit is most pronounced in malnourished children from zinc-deficient regions, where diarrhea duration decreases by approximately 27 hours 3, 4.
For Infants (<6 months)
- Zinc supplementation is not recommended for infants under 6 months of age, as evidence suggests no benefit on diarrhea duration (MD 5.23 hours, 95% CI -4.00 to 14.45) 4, 5.
For Adults and Well-Nourished Children
- No high-quality evidence supports zinc supplementation in well-nourished populations from developed countries or in adults with acute gastroenteritis 3, 4.
- The evidence base is derived primarily from Asian countries with high zinc deficiency prevalence 4.
Critical Limitation: Nausea vs. Diarrhea
The fundamental issue is that zinc has been studied for diarrhea management, not nausea control. While one older guideline mentions zinc reducing "duration of diarrhea and stool output" in cholera 1, none of the evidence addresses nausea as a primary or secondary outcome.
Important Safety Consideration
- Zinc supplementation significantly increases vomiting risk (RR 1.57,95% CI 1.32 to 1.86 in children >6 months; RR 1.54,95% CI 1.05 to 2.24 in infants <6 months) 4, 6.
- This adverse effect directly contradicts the goal of reducing nausea, as zinc may actually worsen upper gastrointestinal symptoms 4, 6.
Recommended Approach for Nausea Management
For nausea in gastrointestinal infections in otherwise healthy adults or older children:
- Prioritize oral rehydration therapy as the cornerstone of management, not zinc supplementation 1, 3.
- Consider antiemetics (such as ondansetron for children >4 years and adolescents) to facilitate tolerance of oral rehydration 1.
- Avoid zinc supplementation in well-nourished populations from developed countries where benefit is unproven and the increased vomiting risk is counterproductive 3, 4.
Clinical Bottom Line
Zinc should not be used to treat nausea in gastrointestinal infections. Its evidence base is limited to diarrhea reduction in young children from zinc-deficient populations, and it actually increases vomiting risk, which would worsen rather than improve nausea symptoms 4, 6.