Why Are Diarrhea Cases More Common in Children During Summer?

In summer, factors such as high temperatures, fluid loss, and potential exposure to contaminated water increase the risk of intestinal infections in children. As a result, the frequency of diarrhea rises significantly during the warmer months.
Children with less mature gut microbiota and weaker immune defenses are more susceptible to water- and food-borne pathogens. Excessive fluid intake can also lead to electrolyte imbalances, a condition often seen alongside diarrhea.
Bacterial or viral infections from contaminated water, children’s swimming pools, sand play areas, spoiled food, or poor hygiene spread more easily in hot weather. These infections can prolong and intensify diarrhea episodes.
In developing countries and in travel destinations where hygiene standards may be insufficient, the risk is further heightened. Therefore, simple, safe, and effective strategies for prevention and treatment are crucial.

What Is Zinc and Why Is It Important?

Zinc is a trace mineral often found to be deficient in our population. It is an inorganic element required in very small amounts for multiple body functions and is a component of numerous enzyme systems.
It is a key constituent of body fluids and tissues, and is present in bones and teeth. Zinc is essential for immune function, nervous system health, antioxidant defense, mitochondrial activity, gut integrity, and hormonal balance.
In gastrointestinal infections—as well as upper respiratory tract infections—zinc can shorten the duration and severity of symptoms and may help prevent illness.
Zinc is present in both plant- and animal-based foods. Daily requirements increase with age: up to 2–3 mg/day for infants under 1 year, and around 5 mg/day by age 4. During illness, requirements can increase even further.
Zinc plays a critical role in immune system function, cell division, and tissue repair. During diarrhea, zinc is rapidly lost from the body, and children with zinc deficiency are more likely to develop diarrhea in the first place. Chronic or temporary zinc deficiency can weaken immunity, delay intestinal epithelial repair, and increase susceptibility to infection.
The World Health Organization (WHO) and UNICEF recommend zinc supplementation for children over 6 months of age with acute or persistent diarrhea—at a dose of 10–20 mg/day for 10–14 days—to both shorten illness duration and reduce the risk of recurrence in the following months.

The Evidence for Zinc Supplementation

1. Shortening the Duration of Diarrhea
A 2024 systematic review found that zinc supplementation shortened diarrhea episodes in children by an average of 13–14 hours. Recovery rates were also higher in the zinc group—a particularly relevant finding for children experiencing frequent summer diarrheal episodes.

2. Greater Effect in Malnutrition
In malnourished children, zinc stores are already depleted. In cases where such children developed diarrhea, zinc supplementation reduced illness duration by about 1 full day. This is particularly important for tackling gastrointestinal infections in developing countries during summer.

3. Reducing Frequency and Recurrence of Diarrhea
Preventive (prophylactic) zinc supplementation studies show that regular intake reduces diarrhea incidence and supports growth in childhood. This could help lower the recurrence rate of diarrhea in the months following the summer season.

How Should Zinc Be Used During Summer?

Target Age Group
Zinc supplementation is recommended for children over 6 months of age with acute or persistent diarrhea. In infants under 6 months, benefits are unclear, so summer treatment protocols should follow this age threshold.

Dosage and Duration
According to WHO guidelines, zinc should be given at a dose of 10–20 mg/day for 10–14 days. Following this regimen can reduce both the duration of acute diarrhea and the likelihood of recurrence within the next 2–3 months.

Possible Side Effects
Zinc supplementation can cause side effects such as nausea and vomiting. Studies indicate a 46% higher likelihood of vomiting in children receiving zinc, although the risk is lower with low-dose formulations. To minimize side effects, dosing should be carefully adjusted, and children monitored throughout treatment.

Practical Recommendations for Summer Use

Co-Administration with Oral Rehydration Solution (ORS)
Zinc treatment should be combined with oral rehydration therapy. This approach restores fluid and electrolyte balance while enhancing zinc’s effectiveness. WHO notes that the zinc-ORS combination can reduce diarrhea-related mortality by up to 93%.

Nutritional Support and Monitoring
During diarrhea episodes, small, nutrient-rich meals should be given alongside zinc to support both energy needs and gut healing. Children should be closely monitored, and medical attention sought if red flags appear (weight loss, dehydration, high fever).

Summer Prevention Strategy
Families traveling during summer can consider short-term, low-dose preventive zinc supplementation for children prone to frequent diarrhea or with nutritional deficiencies—always under medical guidance.

Conclusion and Recommendations

• Summer increases the risk of diarrhea in children, prolonging illness and raising complication risks.
• Zinc supplementation in children aged 6 months–10 years can shorten diarrhea duration, reduce frequency, and prevent recurrence.
• WHO/UNICEF guideline: 10–20 mg/day for 10–14 days.
• Should not be given without monitoring; vomiting should prompt dosage or formulation adjustments.
• Zinc supplementation should always be paired with ORS and proper nutrition.
• Protecting children from diarrhea during summer ensures both a safe holiday and healthy development—zinc can serve as both a therapeutic and preventive tool.

References
Ali, A. A., et al. (2024). Zinc supplementation for acute and persistent watery diarrhea in children under ten years: Systematic review. Journal of Global Health, 14, 04211. https://pubmed.ncbi.nlm.nih.gov/39641338/
Lazzerini, M., & Wanzira, H. (2016). Oral zinc for treating diarrhoea in children. Cochrane Database of Systematic Reviews, (12), CD005436. https://pubmed.ncbi.nlm.nih.gov/27996088/