The 4 Most Important Vitamins and Supplements for Kids

burning questions about how much Vitamin D you need per day, answered
Nutrients and Supplements for Children: Herbs and pills on a table
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Infancy and early childhood are critical times in development, and establishing strong nutritional habits is essential for optimizing health during early life and beyond. Both the World Health Organization and the leading Canadian and American pediatric societies recommend that infants be exclusively fed with breast milk for the first six months of their lives, which should then be complemented with, and eventually replaced by, a wide variety of whole foods. Healthy term infants are largely able to meet their nutritional requirements from breast milk alone, with the exception of vitamin D. While a diverse diet containing a broad array of fruits and vegetables, healthy fats, whole grains, and proteins should provide nearly everything a growing child needs (with the exception of vitamin D, which comes naturally from sun exposure and in which most people are deficient), some children may benefit from additional supplemental nutrients starting at six months of life. 

As parents, navigating the world of nutrients can be overwhelming: which ones are essential? Which are optional? Which ones should be prescribed by a doctor? These are the most commonly prescribed supplements, their benefits, and recommended doses for otherwise healthy infants and children.

Vitamin D

In addition to preventing rickets and supporting healthy bone development, vitamin D has an array of benefits, including to the immune system. Known as the sunshine vitamin, vitamin D deficiency is a common occurrence, especially for those living in northern climates (like here in Canada), where children have limited sun exposure in winter and are strongly encouraged to use sun protection in summer. Breast milk is a poor source of the nutrient and insufficient levels of vitamin D have been linked to lowered immune function, asthma, autism, obesity, and cancer.

Vitamin D dose 

Infants who are partially or exclusively breastfed should be given a supplement of at least 400 international units (IU) and up to 1000 IU of vitamin D daily to prevent deficiency. Once solids have been introduced, children can be offered natural dietary sources of vitamin D such as fatty fish (wild salmon, sardines, tuna), cod liver oil, and egg yolk, while continuing to take at least 400 IU per day. After their first birthday, a child's supplemental vitamin D should be increased to at least 600 IU per day, although depending on the age of the child, up to 4000 IU per day may be safe and necessary to attain optimal vitamin D status.

Vitamin D recommendations based on age1


Recommended Dietary Allowance (RDA) per day

Tolerable Upper Intake Level (UL) per day

Infants 0-6 months

400 IU (10 mcg)

1000 IU (25 mcg)

Infants 7-12 months

400 IU (10 mcg)

1500 IU (38 mcg)

Children 1-3 years

600 IU (15 mcg)

2500 IU (63 mcg)

Children 4-8 years

600 IU (15 mcg)

3000 IU (75 mcg)

Children and Adults 
9-70 years

600 IU (15 mcg)

4000 IU (100 mcg)

(as per Health Canada)

Omega-3 Fatty Acids Benefits

At birth, a child’s brain is only about 50 per cent of the size of their adult brain. Essential omega-3 fatty acids aid in ensuring proper structure and function of the developing human brain. Omega-3s also aid in the regulation of inflammatory pathways, critical in the prevention and treatment of conditions of particular concern in the pediatric population such as eczema, asthma, and depression. These good fats also contribute to lifelong prevention of cardiovascular, metabolic, and other chronic diseases, most of which have their origins in childhood. 

Available in numerous food sources, omega-3s are most commonly associated with EPA- and DHA-rich fish such as wild salmon, mackerel, anchovies, sardines, and herring (check your local fish advisory to avoid the risk of heavy metal toxicity from seafood). While there are plant sources of omega-3s, the human body is inefficient at converting them. 

Low levels of fish consumption contribute to omega-3 fatty acid deficiencies in North Americans, and excessive amounts of other kinds of oils and fats in the diet further create an imbalance of fatty acids in the body. Pregnant and breastfeeding mothers should consume plenty of foods high in EPA and DHA and those who follow a vegan or vegetarian diet should consume a variety of plant-based sources of omega-3 fatty acids such as algae, seaweed, flaxseeds, and walnuts. Talk to your healthcare provider to ensure your child is getting enough!

Omega-3 dosage recommendation

Once solid foods have been introduced, consider a meal of fatty fish two to three times a week (again, checking local advisories), or a daily dose of fish oil with at least 500 mg of mixed EPA and DHA to ensure children are consuming an adequate amount. Child-friendly chewable omega-3 supplements typically do not provide adequate amounts; a liquid form is best.

Probiotics health benefits

There are over five hundred species of microorganisms that line and interact with the human digestive tract. Collectively referred to as the "microbiome," these beneficial bacteria are essential to the health and regulation of the gastrointestinal system, reducing colic and reflux in infants, and gas, bloating, diarrhea, and constipation in older children and adults. Probiotics also play a critical role in the regulation of the immune system and have a profound impact on brain health. A healthy microbiome can reduce the risk of developing allergies, eczema, autoimmune conditions, obesity, mood disorders, and autism. The use of antibiotics early in life, chronic stress, low-fibre diets, and C-sections have all been connected to a disruption of the healthy bacteria that reside in the gut of a child. 

Breast milk nourishes healthy gut bacteria in babies, providing yet another compelling reason to breastfeed. Incorporating fermented foods like cultured vegetables (sauerkraut, kimchi), kefir, and yogurt (ideally plain, full-fat, and homemade, if possible!) into baby's first solids can foster a healthy microbial population. Fibre-rich foods are also critical to a healthy microbiome, acting as prebiotics: foods that feed and nourish the population of beneficial bacteria.

Probiotic dosing

Children who may be at higher risk of an imbalanced gut microbiome due to factors discussed above may benefit from consuming a supplement containing multiple probiotic strains ranging in dose from 5-10 billion colony forming units (CFU). Probiotic supplementation may not be necessary or appropriate for every infant. Consult your healthcare provider prior to initiating a probiotic.


Iron is an essential mineral for developing brain and blood cells. Children who are deficient in iron struggle to grow adequately and learn effectively. The majority of healthy term infants are born with sufficient iron to last four to six months after birth due to stores accumulated in utero and the highly bioavailable form of iron in breast milk. Premature and low birth weight infants are at an increased risk of low iron levels. Beyond six months, infants require additional iron due to their rapid growth and development, their diminished stores, and the declining breast milk supply. Iron deficiency is relatively common among older infants and children, which can lead to disruptions in growth and learning. 

Meat, blackstrap molasses, spinach, raisins, prunes, lentils, and whole grain oats are all great sources of this mineral and should be included in baby’s first foods. Cooking in a cast iron pan may also increase the amount of iron in your child’s diet. An infant or child consuming a vegetarian diet is at a higher risk of iron deficiency as they require nearly twice this amount due to the decreased bioavailability of iron coming from plant sources (known as non-heme iron), but adding foods that are high in vitamin C, such as citrus fruit, peppers or kiwis, will help the iron be more readily absorbed. 

Supportive iron supplementation may be needed over and above consuming iron-rich foods to achieve recommended intakes. Liquid supplements are a simple and effective solution, but it’s important to note that iron toxicity poses a threat to infants and children. Ask your healthcare provider if your child is at risk of iron deficiency before supplementing; a simple blood test will assess this.

Before considering which supplements to implement into your child’s daily routine, try to first add it naturally through diet with the many foods that are high in iron, rich in probiotics, and full of omega-3s. As a general rule, supplemental vitamin D is essential for all babies, children, pregnant women, and for those hoping to become pregnant. Fish oil should be a regular part of pregnancy and breastfeeding and should be included in the child’s diet once solids have been introduced. Probiotics and iron are often indicated, sometimes from birth, although they are not necessary for all children, and carry the risk of adverse effects. Discuss with your family or naturopathic doctor prior to beginning supplementation.

Iron dose

Current recommendations are 11 mg of dietary iron daily for children throughout their first year of life, with minimally decreased requirements during early childhood.

Iron Recommendations Based on Age

Age Recommended Dietary Allowance (RDA) per day Tolerable Upper Intake Level
(UL) per day
Infants 0-6 months 0.27 mg 40 mg
Infants 7-12 months 11 mg 40 mg
Children 1-3 years 7 mg 40 mg
Children 4-8 years 10 mg 40 mg

(as per Health Canada)

To supplement or not to supplement?

Supplemental vitamin D is essential for all children, and fish oil should be strongly considered. Vitamin D should be supplemented to the mother before and during pregnancy, and directly to the child from birth onwards. Fish oil should be a regular part of pregnancy and a breastfeeding mother’s regime, and included in the child’s diet once solids have been introduced. Probiotics and iron are often indicated, sometimes from birth, although they are not necessary for all children, and carry the risk of adverse effects. Discuss with your family or naturopathic doctor prior to beginning supplementation.

Homemade nutrient-rich treats!

Goodies full of goodness that your kids will go for! Here are two easy recipes you can make at home that will give your children a quick, delicious hit of nutrients that we all need.

Iron Kid Energy Bites

Loaded with iron and fibre, these crunchy bites are shaped conveniently into small balls for your child's easy snacking or on-the-go.


  • ¼ cup unsalted raw almonds
  • ¼ cup raw sesame seeds
  • ½ cup whole rolled oats
  • ½ cup dried apricots
  • 1 tbsp fair trade cocoa powder
  • 1 tbsp blackstrap molasses (optional; molasses adds a strong flavour)
  • 1 tbsp water


  1. Grind almonds and sesame seeds into very small pieces in a food processor (important to avoid a choking hazard in small children). Add oats, apricots, cocoa powder, and molasses, and blend until well combined. Add water as needed to achieve a workable consistency. 
  2. Roll the mixture into small, bite-sized balls and freeze or refrigerate. Enjoy with strawberries, kiwis, oranges or another vitamin-C-rich food for a quick hit of absorbable iron!

Make Your Own Yogurt

Try experimenting with different kinds of milk such as cow, goat, almond or coconut milks for richer, tangier flavors!


  • 4 cups full-fat organic milk
  • ½ cup plain yogurt


  1. In a large pot, heat milk over medium heat to approximately 180°F (82°C), or just below the boiling point. Stir constantly to prevent scorching.
  2. Let cool to 120°F (49°C), or just warm enough to comfortably touch.
  3. Combine a ladle of warm milk with the yogurt (also called the “starter) in a bowl and whisk until evenly distributed. Pour the mixture back into the pot and stir to combine well.
  4. Pour milk into a large, warm, glass dish and cover securely.
  5. Reserve ½ - 1 cup in a smaller glass container with a lid to act as your next starter.
  6. Wrap the glass dish in a thick towel and place in a warm, but turned-off, oven for 12 hours. The longer you leave it, the tangier it gets!

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You may also enjoy: Do Probiotic Supplements Improve Health?Top Nutrient Supplements for Healthy Children, and How Vitamin D and Probiotics Support Your Child's Immunity