Understanding a safe amount of magnesium for kids

January 10, 2026 •

3 min read

According to the National Institutes of Health, a significant portion of the population, including children, may not meet the recommended daily intake of magnesium from diet alone. This makes understanding guidelines crucial, especially for parents considering supplementation.

Quick Summary

This article outlines general guidelines for magnesium intake in children by age. It details the benefits of magnesium, sources from food, and general information about supplements to help parents ensure their child's health.

Key Points

RDA for Children: Recommended daily magnesium intake varies by age, ranging from approximately 30 mg for infants (0-6 months) to over 400 mg for adolescent boys.
Supplemental Considerations: General guidelines for supplemental magnesium, not including diet, exist for different age groups.
Food is Preferred: It is generally considered very difficult to consume excessive magnesium from food alone, making dietary sources a preferred option.
Consult a Doctor: Always consult a pediatrician before considering magnesium supplements for a child to determine need and appropriate guidance.
Recognize Potential Deficiency: Be aware of general symptoms like muscle cramps, restlessness, and fatigue, which could potentially indicate a magnesium deficiency.
High-Magnesium Foods: Excellent food sources include leafy greens, nuts, seeds, whole grains, and legumes.

Recommended Dietary Allowance (RDA) for Children

Magnesium is an essential mineral vital for hundreds of bodily processes, including bone development, muscle and nerve function, and energy production. The amount a child may need changes as they grow. The Recommended Dietary Allowance (RDA) is the average daily intake level sufficient to meet the nutrient requirements of nearly all healthy individuals in a particular life stage.

Infants 0–6 months: Adequate Intake (AI) is generally considered to be around 30 mg per day.
Infants 7–12 months: Adequate Intake (AI) is generally considered to be around 75 mg per day.
Children 1–3 years: The RDA is generally around 80 mg per day.
Children 4–8 years: The RDA is generally around 130 mg per day.
Children 9–13 years: The RDA is generally around 240 mg per day.
Teens 14–18 years (Male): The RDA is generally around 410 mg per day.
Teens 14–18 years (Female): The RDA is generally around 360 mg per day.

Upper Intake Levels (UL) for Magnesium Supplements

While it is nearly impossible to get too much magnesium from food, excessive amounts from supplements can potentially be harmful and cause unpleasant side effects. For this reason, the NIH has established tolerable Upper Intake Levels (ULs) specifically for supplemental magnesium.

Children 1–3 years: The UL for supplemental magnesium is generally around 65 mg per day from supplements.
Children 4–8 years: The UL for supplemental magnesium is generally around 110 mg per day from supplements.
Children and teens 9–18 years: The UL for supplemental magnesium is generally around 350 mg per day from supplements.

It is vital to consult with a pediatrician before giving any magnesium supplements to a child, as they can accurately assess if supplementation is necessary and provide appropriate guidance.

Food Sources vs. Supplements

Most children can get the magnesium they may need from a balanced diet rich in fruits, vegetables, whole grains, nuts, and seeds. Focusing on food-based sources is often the safest and most recommended approach.

Magnesium in Common Foods

Pumpkin Seeds (1/4 cup): May contain around 150-175 mg
Spinach (1 cup, cooked): May contain around 155 mg
Almonds (1 ounce): May contain around 80 mg
Black Beans (1/2 cup): May contain around 60 mg
Edamame (1/2 cup, cooked): May contain around 50 mg
Avocado (1/2 medium): May contain around 23 mg
Banana (1 medium): May contain around 35 mg

Symptoms of Magnesium Deficiency in Children

Magnesium deficiency is relatively uncommon in healthy children but can occur. It can be difficult to diagnose because early signs are often subtle. Parents should be aware of the following general symptoms:

Muscle cramps and twitches: Involuntary muscle movements or spasms.
Restless sleep: Difficulty falling or staying asleep.
Irritability and mood swings: Changes in mood or increased nervousness.
Fatigue and weakness: General tiredness and low energy levels.
Teeth grinding: Also known as bruxism.
Constipation: Magnesium helps regulate bowel movements, and low levels can contribute to constipation.

Considerations Regarding Excessive Magnesium Intake

While the body typically excretes excess magnesium from food, high-dose supplements can potentially overwhelm this process. Symptoms can range from mild gastrointestinal issues to potentially more serious problems in extreme cases.

Mild symptoms: May include nausea, diarrhea, and abdominal cramping.
Serious symptoms: May include low blood pressure, muscle weakness, confusion, slow breathing, and irregular heartbeat.

Magnesium Intake: Food vs. Supplements


Feature	Magnesium from Food	Magnesium from Supplements
Source	Naturally occurring in a variety of foods like leafy greens, nuts, and seeds.	Concentrated mineral in tablet, liquid, or powder form.
Safety	Generally considered very safe; excess is naturally excreted, toxicity is highly unlikely.	May pose risks if taken in excessive amounts potentially beyond general guidelines.
Absorption	May be absorbed more gradually and efficiently in conjunction with other nutrients.	May be absorbed more quickly, which could potentially cause side effects if taken in higher amounts.
Regulation	Generally regulated by the body's natural excretory processes.	May require careful consideration of amounts and potentially medical supervision.

Conclusion: Prioritize Diet First

For most healthy children, obtaining magnesium from a diverse diet is often a safe and effective strategy. A pediatrician or a registered dietitian can help create a balanced meal plan incorporating magnesium-rich foods. Supplementation should generally only be considered under the guidance of a healthcare professional, especially for children with a diagnosed deficiency or a specific medical condition. Adhering to general guidelines is essential to potentially ensure a child's safety and well-being. Always store supplements out of children's reach to prevent accidental ingestion.

For more detailed information on nutrient reference values, consult the National Institutes of Health Office of Dietary Supplements website.

Frequently Asked Questions

For a child between 4 and 8 years old, the Recommended Dietary Allowance (RDA) for magnesium is generally considered to be around 130 mg per day.

It is generally considered highly unlikely for a child to consume too much magnesium from food sources alone, as the body will typically excrete any excess.

Excessive intake of magnesium from supplements could potentially lead to side effects such as nausea, diarrhea, abdominal cramping, and, in severe cases, low blood pressure or an irregular heartbeat. It's important to consult a healthcare professional for guidance.

Great food sources for magnesium include leafy green vegetables like spinach, nuts, seeds (like pumpkin seeds), whole grains, legumes, and bananas.

Magnesium supplements should generally only be considered after a consultation with a healthcare provider who can assess the child's needs and provide appropriate guidance. Dietary sources are often the preferred first option.

Yes, different forms exist. For example, magnesium citrate is sometimes used, but a pediatrician can help determine if a supplement is needed and advise on appropriate forms.

Signs could potentially include continuous vomiting, muscle weakness, slow breathing, and low blood pressure. If you have concerns, seek immediate medical attention.