Immune supplements for children: which are safe and when it’s really worth giving them
Vitamin D3, C, zinc, LGG probiotics, elderberry – what actually strengthens children's immunity, safe doses, and when it's really worth supplementing.
Every year, as the infection season begins, pharmacies fill up with 'immunity' preparations for children. Some of them have solid scientific foundations – some are expensive placebos. This article presents supplements for which there is real evidence supporting children's immunity, safe doses tailored to age, and important warnings: what to give cautiously and what to avoid altogether. A key disclaimer: supplementation in children always requires consultation with a pediatrician.
KEY INFORMATION
• Vitamin D3 600 IU/day (autumn–spring) – The Polish Pediatric Society recommends supplementation from infancy throughout the year when sun exposure is insufficient.
• Probiotics LGG (Lactobacillus rhamnosus GG) – the best-researched strain in children; Cochrane 2019 confirms the reduction of infectious diarrhea and the duration of infections.
• Zinc and vitamin C – effective in cases of deficiency; routine megadosing is unjustified and potentially harmful.
• Elderberry (Sambucus) – safe from 1 year of age in processed forms; shortens the duration of infections.
• Adaptogens, melatonin, retinol in high doses – NOT without a clear doctor's indication.
Vitamin D3 – the most important supplement for children's immunity
Vitamin D3 is a steroid hormone regulating hundreds of genes, including those crucial for the immune system: vitamin D receptors (VDR) are found on T cells, B cells, macrophages, and NK cells. D3 increases the production of cathelicidins (antibacterial peptides) and defensins (antiviral peptides). A deficiency of D3 in children is associated with an increased susceptibility to respiratory infections (Martineau et al., BMJ 2017 – meta-analysis of 25 RCTs, n=11,321: D3 reduced the risk of respiratory infections by 12% overall, by 70% in individuals with baseline deficiency).
Recommendations of the Polish Pediatric Society (updated 2022): infants 0–6 months breastfed: 400 IU/day from birth; infants 7–12 months: 400–600 IU/day; children 1–10 years: 600 IU/day in the autumn–spring period (or all year round with insufficient sun exposure); children 11–18 years: 600–1000 IU/day. In case of suspected deficiency (lack of sun exposure, obesity, dark skin, absorption disorders), test for 25(OH)D and adjust under medical supervision. Safe upper limit (UL): 1000 IU/day for infants; 2500 IU for children 1–8 years; 4000 IU for children over 9 years. Note: D3 preparations for children usually contain 400–600 IU in a single dose – do not double the dose.
Probiotics LGG and other strains – what really works
Lactobacillus rhamnosus GG (LGG) is the best-researched probiotic strain in children – over 800 randomized clinical trials. Clinical outcomes of LGG in children: infectious diarrhea – Cochrane meta-analysis (Szajewska and Mrukowicz 2019): LGG significantly shortened the duration of infectious diarrhea (by ~1 day) and reduced the risk of diarrhea lasting more than 3 days; antibiotic-associated diarrhea – LGG reduced the incidence by ~60%; respiratory infections – studies by Hojsak et al. (Clinical Nutrition, 2010): LGG 10⁹ CFU/day reduced the risk of respiratory infections by 33% and diarrhea by 57% in children in daycare. LGG is produced in Poland and is available in many pediatric preparations. Correct dosing: 10⁸–10¹⁰ CFU/day; for a course (1–3 months) or together with antibiotics and for 2 weeks after.
Other tested strains in children: Lactobacillus reuteri DSM 17938 – infant colic (Savino et al. 2007); Bifidobacterium lactis Bb12 – infants, enhancing immune response; Streptococcus salivarius K12 – throat infections in school-aged children. Multi-strain probiotics are not automatically better than monotherapy with a well-studied strain – buy a product with a confirmed strain and CFU, not a 'culture mix'.
Vitamin C – effective in deficiencies, not as a megadose
Vitamin C is essential for the proper functioning of the immune system: it supports neutrophil chemotaxis, lymphocyte proliferation, interferon synthesis, and is a cofactor for collagen (mucosal barriers). A deficiency of vitamin C (below 11 µmol/L) is associated with increased susceptibility to infections. However, megadosing vitamin C in children without deficiency does not significantly shorten the duration of colds – Cochrane meta-analysis by Hemilä and Chalker (2013): preventive supplementation of C does not reduce the incidence of colds in the general population; it shortens the duration in individuals who exercise regularly or are exposed to intense physical effort by 8–14%. Correct RDA doses for children: infants up to 6 months – 40–50 mg/day (covered by breast milk); children 1–3 years – 15 mg/day; 4–8 years – 25 mg/day; 9–13 years – 45 mg/day; 14–18 years – 65–75 mg/day. These doses are met by a diet rich in fruits and vegetables (1 orange = ~70 mg C). Supplementation makes sense in cases of deficiency (children with a diet low in vegetables/fruits) or with intense physical effort.
Zinc – important, but only in case of deficiency
Zinc is a cofactor for over 300 enzymes and a regulator of the immune system. Zinc deficiency is common globally (about 2 billion people) and is associated with: impaired maturation of T lymphocytes, reduced production of thymulin (thymus hormone), increased susceptibility to respiratory infections and diarrhea. Clinical studies in children (Zinc meta-analysis, Brown et al., American Journal of Clinical Nutrition, 2002): zinc supplementation in children with deficiency reduced the incidence of diarrhea by 18% and respiratory infections by 14%. The study by Bhatnagar et al. (Pediatrics, 2004): zinc 10 mg/day for 4 months in Indian children with deficiency – reduced diarrhea morbidity by 30%. The problem: in Poland, zinc deficiencies are not common in healthy children with a normal diet containing meat, dairy, and grain products. Routine zinc administration without deficiency may lead to impaired copper absorption (zinc and copper compete for intestinal transport) and paradoxical immune weakening. Safe doses: see RDA table; do not exceed UL (upper limit). supplements for children
Our observations: The most common mistake parents make is giving zinc 'just in case' throughout the winter – especially preparations with 10–15 mg of zinc daily, which exceed the UL for children aged 1–4 years (7 mg/day). If the child eats meat (red meat, poultry) and dairy – there is no lack of zinc in the diet. Supplementation makes sense mainly for children on plant-based diets or with confirmed deficiencies. In case of doubts, it is worth checking the serum zinc level (normal: 70–120 µg/dl) instead of supplementing prophylactically for many months.
Elderberry (Sambucus nigra) – evidence for shortening infections
Elderberry extract contains anthocyanins (cyanidin-3-glucoside, cyanidin-3-sambubioside) and chlorogenic acid with antiviral properties. Mechanism: elderberry flavonoids inhibit the binding of influenza viruses and rhinoviruses to cell receptors; they also have immunostimulatory effects (cytokine activation). Clinical studies: Tiralongo et al. (Nutrients, 2016): Sambucus syrup in travelers – shortened the duration of colds by 2 days compared to placebo; milder symptoms. Zakay-Rones et al. (Journal of International Medical Research, 2004): sambucus in influenza – shortened the duration by 3.5 days. Most studies were conducted on adults – there is less data on children, but the mechanism is the same.
Safety for children: raw, unripe elderberry fruits and leaves contain sambunigrin (cyanogenic glycoside) that can cause nausea and vomiting; processed forms (syrups, lozenges, pasteurized or cooked products) are safe – sambunigrin is thermally inactivated; recommended age: from 1 year of age (syrups without alcohol and artificial colors); do not use in infants under 1 year of age. Typical syrup doses (250–700 mg extract): children 1–5 years: 1 teaspoon (5 ml) once daily; children 6–12 years: 1–2 teaspoons daily. For a course (during infection) or prophylactically during the infection season.
What NOT to give children – list of unjustified supplements
Supplements that should not be given to children without clear medical indication: melatonin (for children under 12 years – only under the supervision of a neurologist or pediatric psychiatrist; EFSA and AAP do not recommend routine use; sleep disorders require diagnostics, not supplementation); adaptogens (ashwagandha, rhodiola, ginseng, maca) – lack of safety studies in children; hormonal receptors and pathways are still maturing; do not use without indication; vitamin A (retinol) in doses above RDA – toxic with accumulation (hepatotoxic, teratogenic, causes intracranial pressure with overdose); multivitamin preparations containing retinol often cover the UL with a normal diet; cod liver oil (fish oil) contains both D3 and retinol – be cautious of total doses; preparations with undocumented composition 'for immunity' – colloidal silver, so-called 'antioxidant shields', products containing raw plant extracts without pediatric studies. vitamin K2 and D3
Omega-3 DHA and children's immunity – the role of fatty acids
Omega-3 fatty acids (EPA and DHA) regulate the inflammatory response through the synthesis of resolvins and protectins – mediators that resolve inflammation. DHA is also a key component of the cell membranes of lymphocytes and macrophages, influencing their functional activity. Studies in children: Thienprasert et al. (Journal of Nutrition, 2009): children supplemented with DHA 400 mg/day for 16 weeks had significantly fewer days with respiratory illness and fewer school absences than placebo. Omega-3 is particularly important for children with: low fish consumption (marine fish – the main source of EPA/DHA); vegan or vegetarian diets (lack of EPA/DHA from ALA is very poor); frequent respiratory infections.
DHA doses for children: infants 0–12 months breastfed – breast milk contains DHA (the mother should supplement 200–300 mg DHA/day); infants 0–12 months formula-fed – choose DHA-enriched milk; children 1–3 years – 70 mg DHA/day (EFSA); children 4–18 years – 250 mg EPA+DHA/day (EFSA). Sources: cod liver oil (fish oil), krill oil, algae (vegan form – algae are the primary source of DHA in the food chain). Fish oil contains both D3 and vitamin A – when supplementing with cod oil, be cautious of total retinol doses.
When to see a doctor instead of reaching for a supplement
Immunity-supporting supplements are suitable as a complement when a child is sick on average (6–8 infections per year in preschool children is normal). However, there are situations that require diagnostics, not supplementation: the child gets sick more than 8–10 times a year with severe infections (pneumonia, severe ear infections, sinusitis requiring hospitalization); infections are more severe than in peers, with complications; the child needs repeated antibiotics; infections are caused by rare or opportunistic microorganisms. In these cases, consultation with a pediatric immunologist is a priority. Primary immune deficiencies (PID) are often diagnosed too late, as 'masked' symptoms are subsequent infections treated as normal.
Important context: 6–8 respiratory infections per year in a preschool child is biologically normal – it is a time of 'training' the immune system. Children attending daycare and preschool get sick more than children at home – this is not 'weak immunity', but exposure to new microorganisms. Supplements do not replace the natural process of immune maturation. A good diet (varied, rich in vegetables, fruits, protein), sleep (10–12 hours for school-aged children), and outdoor physical activity have a much greater impact on immunity than any supplement. The child's gut microbiome, shaped by the first 3 years of life, is the foundation of immunity – fermented products (kefir, natural yogurt, pickles) and prebiotic fiber support it more effectively than over-the-counter supplements.
How to build a supplementation protocol for a child – a practical guide
There is no one universal supplementation protocol for children – as children differ in age, diet, activity level, and sun exposure. However, a rational minimum can be indicated: year-round (or autumn-spring): vitamin D3 in a dose appropriate for age (see table) + K2 MK-7 if D3 ≥2000 IU (standard preventive doses usually do not require K2); omega-3 DHA 150–250 mg/day if the child does not eat marine fish ≥2× a week; during antibiotic therapy and for 2 weeks after: LGG 10⁸–10¹⁰ CFU/day; with a diet low in vegetables and fruits: vitamin C at RDA (not megadoses); during the infection season (optional): elderberry (Sambucus) in syrup form.
What to avoid in the pediatric protocol: multivitamins with retinol + fish oil + D3 at the same time (risk of exceeding the UL of vitamin A); zinc + iron at the same time (competition for transporters); probiotics in children with immunodeficiencies or after major surgeries (risk of bacteremia/fungemia with live cultures). When purchasing supplements for children: look for products with clearly marked doses, quality certification (GMP), without artificial colors and synthetic sweeteners (aspartame, saccharin). Liquid and chewable forms are better accepted by children than tablets.
Frequently Asked Questions
Below are answers to parents' questions regarding immune-supporting supplements for children.
Which supplements actually strengthen a child's immunity?
The best documented: D3 (600 IU/day, especially autumn-spring), probiotics LGG (reducing diarrhea and respiratory infections), zinc and vitamin C (only with confirmed deficiency), elderberry (shortens the duration of infections). All after consultation with a pediatrician. 6–8 infections per year in a preschool child is normal, not an indication for intensive supplementation.
How much vitamin D3 should a child receive?
According to PTP 2022: infants 0–6 months – 400 IU; 7–12 months – 400–600 IU; 1–10 years – 600 IU (autumn-spring, or all year round with little sun); 11–18 years – 600–1000 IU. In case of deficiency of 25(OH)D – correction under medical supervision. Do not exceed UL: 2500 IU for children 1–8 years.
Is zinc safe for children?
Yes, in RDA doses. Do not exceed UL (7 mg/day for children 1–3 years; 12 mg for 4–8 years; 23 mg for 9–13 years). Do not give zinc 'prophylactically' for many months without indication – with a normal diet including meat and dairy, deficiencies are rare.
Do probiotics help with children's immunity?
Yes, especially LGG has over 800 RCT confirming effectiveness in reducing infectious and post-antibiotic diarrhea and respiratory infections. Use LGG 10⁸–10¹⁰ CFU/day in courses or during antibiotic therapy.
Is elderberry safe for children?
Processed forms (syrups, lozenges) – safe from 1 year of age. Raw, unripe fruits and leaves – do not give (contain sambunigrin). Shortens the duration of colds and flu in adults; fewer studies in children, but used safely in clinical practice.
What supplements should not be given to children?
Without a doctor's indication: melatonin (under 12 years), adaptogens (ashwagandha, rhodiola), high doses of retinol (vitamin A), colloidal silver. When in doubt – always consult a pediatrician before supplementation.
This article is for informational and educational purposes and does not constitute medical advice. Before starting to use cannabis or CBD for therapeutic purposes, consult a doctor, especially if you are taking other medications, are pregnant, or breastfeeding.
Author: Michał Waluk · Published: 2026-05-04 · Updated: 2026-05-04
