Supplements for children: what is safe, what is worth giving, and what should absolutely be avoided

In a survey among parents of 2826 children from educational institutions in Krakow, 72.2% of children took dietary supplements, with vitamin D being the most popular (Piórecka et al., Nutrients 2024). The scale is therefore large, and the number of ingredients with solid pediatric data remains small. Most products "for immunity" and "for concentration" lack studies on children, and doses are often calculated from studies on adults. This is a misleading simplification: a child weighs less, has lower official intake limits, and different toxicity thresholds. In this text, you will find what can be supported by guidelines: vitamin D doses from recommendations for Poland, conditions for iron supplementation, probiotic strains with evidence, and a list of things we do not give to children. We analyze the products advertised for immunity in a separate entry. on immunity supplements for children.

KEY INFORMATION
• After winter, 64% of Polish children aged 9-13 had a vitamin D deficiency, with 20.2% experiencing severe deficiency (Chlebna-Sokół et al., European Journal of Nutrition 2019).
• Vitamin D dosages for children are established in guidelines for Poland and depend on age, from 400 IU in newborns to 2000 IU in teenagers.
• Iron is only administered after confirming a deficiency through testing; prophylactically only in premature infants and children with low birth weight, at the doctor's request.
• Melatonin is the most common cause of unintentional poisonings in children under 6 in the United States.

Does every child need supplements?

No. A healthy child with a varied diet in Poland needs one supplement: vitamin D. Everything else requires indication, most often confirmed by a blood test. The order is the opposite of what is seen in advertisements: first, the question of what the child is lacking, then the supplement.

The reason for this caution is simple. Pediatric data for most ingredients simply do not exist, and the manufacturer is not obliged to present them, as a supplement is not a medicine and does not undergo registration studies. Where authorities have set safety limits, they are clearly lower for children than for adults. The European Food Safety Authority has established the upper tolerable intake level for vitamin D at 50 µg per day (2000 IU) for children aged 1-10 years and 100 µg (4000 IU) for adolescents aged 11-17 years, justifying the lower value by the lower body weight (EFSA Journal 2023). For infants, the limit is even lower: 25 µg up to 6 months and 35 µg from 6 to 12 months, with these two values coming from a separate opinion from 2018, which the 2023 document upholds.

A separate issue is fat-soluble vitamins: A, D, E, and K. They accumulate in the liver and fatty tissue, so their excess is not excreted in urine like excess vitamin C. A clinical review from 2026 indicates infants and children with absorption disorders as the group most at risk for both deficiency and toxicity from these vitamins (Paparella et al., Current Medicinal Chemistry 2026). Therefore, when taking a multivitamin, the total sum of doses from all products the child receives matters.

How much vitamin D should a child receive?

The dose depends on age and is based on guidelines for the Polish population, not parental discretion. An infant up to 6 months receives 400 IU of cholecalciferol daily from the first days of life, regardless of the feeding method. A child aged 1-3 years: 600 IU throughout the year. An adolescent aged 11-18 years: 1000-2000 IU.

These numbers come from an update of recommendations developed by a team led by Paweł Płudowski (Nutrients 2023), which replaced an earlier version endorsed by the Polish Society of Pediatric Endocrinology and Diabetology (Rusińska et al., Frontiers in Endocrinology 2018). An infant aged 6-12 months receives 400-600 IU, depending on how much vitamin D is in their meals. A child aged 4-10 years who does not spend 15-30 minutes a day in the sun from May to September with exposed forearms and legs needs 600-1000 IU throughout the year.

Why this emphasis? A study of 720 healthy children aged 9-13 from six regions of Poland showed that in March, 64% of them had 25(OH)D levels in the deficiency range, and 20.2% had severe deficiency. In October, the percentage dropped to 25.9%, but summer alone did not solve the problem (Chlebna-Sokół et al., European Journal of Nutrition 2019). The target concentration in a child is 30-50 ng/ml, and values above 100 ng/ml indicate a risk of toxicity and a mandate to discontinue supplementation. This is important for high-dose products intended for adults.

Is it worth giving omega-3 to a child?

Fish yes, capsules not necessarily. Docosahexaenoic acid builds neuronal and retinal membranes, so the idea of adding it seems logical, but studies on supplementation in children born at term have been disappointing. A Cochrane review included 15 studies with 1889 infants and did not confirm a consistent benefit.

The authors examined visual acuity, neurological development, and growth after enriching the formula with long-chain polyunsaturated fatty acids. One meta-analysis of three studies showed an improvement in visual acuity measured by evoked potentials at 12 months, while another, based on Teller cards, showed no difference. Observations at ages 3, 6, and 9 years showed no effect. The authors' conclusion is clear: routine enrichment of formulas for infants born at term cannot currently be recommended (Jasani et al., Cochrane Database of Systematic Reviews 2017).

What does this mean in practice? Omega-3 from fish remains a part of a normal diet, and no one disputes that, but buying a bottle of drops won't make up for a fish-free diet. If a child does not eat fish at all, for example on a plant-based diet, it is worth discussing supplementation with a pediatrician, who will adjust the dose according to age and body weight. The numbers on packages intended for adults do not translate to children. You can find more about fatty acids in the post on the properties and dosing of omega-3.

When does a child really need iron?

Only when a deficiency is confirmed by testing, or when prophylaxis is prescribed by a doctor for a premature infant or a child with low birth weight. WHO defines iron deficiency as ferritin levels below 12 µg/l in children up to 5 years and below 15 µg/l in older children. Without this result, iron is not a supportive supplement, but a burden that the child does not need.

Recommendations developed by the Polish Pediatric Society in collaboration with pediatric hematology, neonatology, and family medicine societies calculate the therapeutic dose per kilogram of the child's body weight and indicate that a lower dose works just as well as a higher one, and less frequently causes gastrointestinal discomfort (Chaber et al., Nutrients 2024). This same document outlines the harms of overdose: delayed growth and development of the nervous system, disruption of trace element metabolism, increased susceptibility to infections, and disruption of gut microbiota development. The specific number of milligrams is prescribed by a doctor after seeing the result, which is why we do not provide it here. The authors also emphasize that the frequency of iron deficiency in Polish children is not known; European estimates range from 4% to 18% in infants aged 6-12 months and from 4% to 41% in children aged 1-3 years.

There is also a purely incidental reason. Iron is among the most dangerous household poisons for small children, and a typical source is the mother's prenatal tablets. In a series of five cases from the pediatric intensive care unit, the average age of the patients was 25.8 months, all had swallowed the mother's supplement, and two children died from acute liver failure (Chandran et al., Journal of Family Medicine and Primary Care 2023). Keep iron preparations out of reach of children.

Which probiotics have evidence in children?

Two strains stand out from the rest: Saccharomyces boulardii and Lactobacillus rhamnosus GG. The effect is attributed to a specific strain, not to bacteria in general, so a product described simply as "probiotic" does not have documented effects, even if it costs more.

In a meta-analysis of 21 studies involving 4780 people, S. boulardii reduced the risk of antibiotic-associated diarrhea from 18.7% to 8.5%, and in the subgroup of children from 20.9% to 8.8% (Szajewska and Kołodziej, Alimentary Pharmacology and Therapeutics 2015). For LGG, the same authors collected 12 studies involving 1499 individuals: the risk of antibiotic-associated diarrhea decreased from 22.4% to 12.3%, with the difference being significant only in children, and the quality of evidence was rated as moderate to low (Szajewska and Kołodziej, Alimentary Pharmacology and Therapeutics 2015). In acute gastroenteritis, a review of 18 studies involving 4208 children showed an average reduction in diarrhea of 0.85 days, with this value coming from 15 studies and 3820 children, and the authors note a high heterogeneity of the samples (Szajewska et al., Alimentary Pharmacology and Therapeutics 2019).

The practical conclusions are three. Look for the full strain designation on the label, not just the genus name. In studies on preventing antibiotic-associated diarrhea, the preparation was administered together with the antibiotic, not after the treatment ended, so only this scheme has been tested. In a child with a severe underlying illness, with a central catheter, or with immune disorders, the decision is made by the doctor: nearly a hundred cases of blood infection from yeast originating from the preparation have been described, although not in individuals with normal immunity (Kelesidis and Pothoulakis, Therapeutic Advances in Gastroenterology 2012). We write more about this in the post o wyborze szczepu probiotycznego.

Is melatonin safe for a child?

Data is limited and primarily concerns children with neurodevelopmental disorders. A systematic review published in 2026 states outright that melatonin is the most common cause of unintentional drug poisoning in children aged 0-6 years, and there is a lack of data on its effectiveness in typically developing children.

The authors analyzed 19 publications. Interventional studies included a total of 167 young children with neurological disorders, mainly from the autism spectrum, and showed a reduction in sleep onset time with a small number of adverse events. Outside this group, there is no evidence, and observational data show an increasing number of prescriptions, prolonged use, and cases of overdose (Kracht et al., JAMA Network Open 2026). The American Poison Control Center recorded a total of 260,435 reports concerning children and adolescents from 2012 to 2021, with an annual increase of 530%. Five children required mechanical ventilation, and two died (MMWR 2022).

Concerns about the impact on sexual maturation remain hypothetical. In a Dutch observation of 51 children treated with an average of 2.7 mg of melatonin for 3.1 years, the advancement of maturation on the Tanner scale did not differ from values published for peers (van Geijlswijk et al., Psychopharmacology 2011). This is a study without a control group, so it resolves little. The problem is therefore not a confirmed hormonal disorder, but the lack of basis for administering melatonin to a child who sleeps poorly for behavioral reasons. Start with consistent sleep hours, evening calming, and removing screens, and if that doesn't help, go to a pediatrician instead of a pharmacy.

What should not be given to children and why?

The following list includes only items with documented harm or well-described lack of pediatric data. What could not be supported by a source is not included here.

Vitamin A causes the most misunderstandings. Retinol from supplements is dangerous, not beta-carotene from carrots or spinach, as the body regulates its conversion itself. The EFSA maintained the limit of 3000 µg of retinol equivalent per day for adults and scaled it for children based on body weight, resulting in values from 600 µg for infants to 2600 µg for teenagers (EFSA Journal 2024). Check how much retinol is in your child's multivitamin before adding cod liver oil.

How to read a supplement label for a child?

Start with the daily portion and adjust it based on what the child is already getting from other products. Then check the form of the ingredient, and for probiotics, the full strain designation. Finally, look at the form: gummies look like candy, so the child reaches for them on their own.

The declared content can often be the weakest link. In an analysis of 30 melatonin products, the actual content ranged from 83% below to 478% above the declaration, with the most significant deviation being a chewable tablet containing nearly 9 mg of melatonin instead of the declared 1.5 mg; differences between batches of the same product reached 465%. Additionally, serotonin was detected in eight products (Erland and Saxena, Journal of Clinical Sleep Medicine 2017). Therefore, when choosing supplements for children, select manufacturers that publish batch test results, not just the prettiest packaging.

Gummies have two more drawbacks that are rarely mentioned in advertisements: they add sugar to a child's daily intake and eliminate the natural barrier against overdose. This is illustrated by a case report from the journal Pediatric Emergency Care: a 20-month-old girl was admitted to the intensive care unit with a calcium level of 20.7 mg/dl and vitamin D poisoning after weeks during which her mother gave her calcium-vitamin gummies several times a day. The authors describe this as a case of neglect due to the mother's mental illness, and the hospitalization was long and complicated (Doyle i in., 2021). Treat gummies like medicine: a measured portion, locked cabinet, out of the child's reach.

When to examine the child and when to go to the pediatrician?

Testing instead of guessing makes sense when the result will change the decision. Three tests are enough to start: a complete blood count with ferritin if iron deficiency is suspected, 25(OH)D after long supplementation or its absence, and vitamin B12 for a child on a plant-based diet. The pediatrician issues the referral and interprets the result.

Go to the doctor without waiting for tests if the child is pale and quickly fatigues, has stopped gaining weight, has recurring diarrhea, or has changed behavior and appetite without an obvious cause. These are situations where a supplement bought independently delays diagnosis. Schedule an appointment also when the child is on regular medication, as some ingredients alter their absorption.

A separate plan is required for a vegan diet. The position of the ESPGHAN Nutrition Committee from 2025 recommends that infants, children, and adolescents on such a diet be under the constant care of a dietitian and pediatrician and receive supplementation of indicated micronutrients, with vitamin B12 at the forefront, as it is not found in plant products (Verduci et al., Journal of Pediatric Gastroenterology and Nutrition 2025). Undiagnosed B12 deficiency develops over months without clear symptoms, and its neurological effects can be irreversible, so this is not an area for self-experimentation.

Frequently Asked Questions

How much vitamin D should a child receive?

According to guidelines for Poland, infants up to 6 months receive 400 IU daily, from 6 to 12 months 400-600 IU, children aged 1-3 years 600 IU throughout the year, children aged 4-10 years 600-1000 IU, and adolescents aged 11-18 years 1000-2000 IU. The target concentration of 25(OH)D is 30-50 ng/ml (Płudowski et al., Nutrients 2023).

Can children take omega-3?

Include fish in the diet, but capsules are not necessarily required. A Cochrane review from 2017, covering 15 studies and 1889 term infants, found no consistent developmental benefit from adding DHA to formulas. If the child does not eat fish, adjust the supplement dosage with the pediatrician, not based on adult packaging.

Is melatonin safe for children?

The data mainly concerns children with neurodevelopmental disorders. A systematic review from 2026 found no data on effectiveness in typically developing children and reminds that melatonin is the most common cause of unintentional poisoning in children under 6 years old. For sleep issues, start with sleep hygiene and consultation with a pediatrician.

When does a child need iron from a supplement?

Only after confirming a deficiency through testing, and prophylactically only in premature infants and children with low birth weight. WHO considers ferritin levels below 12 µg/l in children up to 5 years and below 15 µg/l in older children as deficient. The therapeutic dose is calculated per kilogram of body weight and prescribed by a doctor. Iron without deficiency disrupts the balance of trace elements and the development of gut microbiota.

Are gummy vitamins safe for children?

The problem is not the composition itself, but the ease of overdose and added sugar. In a case report from Pediatric Emergency Care, a 20-month-old girl was admitted to intensive therapy with a calcium level of 20.7 mg/dl after weeks of receiving vitamin D and calcium gummies several times a day. Count the pieces, keep the packaging out of reach of children, and sum the doses from all preparations.

Which probiotics have evidence in children?

Saccharomyces boulardii reduced the risk of diarrhea after antibiotics in children from 20.9% to 8.8%, while Lactobacillus rhamnosus GG shortened infectious diarrhea by an average of 0.85 days in a review of 18 studies involving 4208 children, with this result coming from 15 of them (Szajewska et al., 2015 and 2019). A product without a specified strain designation has no documented clinical effect.

If you are looking for products for yourself, you can browse the assortment in the category. supplementsLeave the decision about the child's supplementation to the pediatrician.

This article is for informational and educational purposes and does not constitute medical advice. Before starting supplementation, consult your doctor, especially if you are taking medications regularly, are pregnant or breastfeeding, or have a chronic illness.

Author: Michał Waluk · Opublikowano: 2026-06-02 · Aktualizacja: 2026-08-11