There isn’t one single “best” vitamin for every child. The nutrients your child needs most depend on their age, diet, and growth stage. That said, vitamin D stands out as the most universally recommended supplement for children: the American Academy of Pediatrics recommends 400 IU daily for all breastfed infants, and national survey data shows that over 94% of Americans ages 4 and older fall short of daily vitamin D requirements. Beyond vitamin D, iron, calcium, and a handful of other nutrients round out the list of what children most commonly lack.
Vitamin D: The Most Widely Recommended
Vitamin D helps children absorb calcium, build strong bones, and support immune function. It’s the one nutrient that nearly every pediatric health organization flags as a priority. The AAP recommends 400 IU per day starting in the first days of life for breastfed and partially breastfed infants, since breast milk alone doesn’t provide enough. Formula-fed babies who drink less than about 32 ounces of fortified formula daily also need a supplement.
For older children and teens, the recommendation stays at 400 IU per day if they aren’t getting that amount from fortified milk, fortified cereals, or other dietary sources. Children with darker skin, those who live in northern climates, and kids who spend limited time outdoors are at higher risk of falling short. A simple liquid drop supplement for infants, or a chewable tablet for older kids, typically covers the gap.
Iron: Critical for Toddlers
Iron fuels brain development and helps red blood cells carry oxygen throughout the body. Toddlers ages 1 to 3 need about 7 mg of iron per day, and this age group is particularly vulnerable to deficiency because many toddlers are picky eaters and transition off iron-fortified formula. Signs of low iron in children include unusual tiredness, pale lips or nail beds, poor appetite, frequent infections, irritability, and slowed growth. Some children develop cravings for non-food items like ice or dirt.
Red meat, beans, fortified cereals, and spinach are good dietary sources. If your child’s diet is limited, a multivitamin with iron or a standalone iron supplement can help, but iron is one nutrient where more isn’t better. Keep iron-containing supplements out of reach, since accidental overdose is a leading cause of poisoning in young children.
Calcium: Growing Bones Need It
Calcium requirements change significantly as children grow. Kids ages 1 to 3 need 700 mg daily. That jumps to 1,000 mg for ages 4 to 8, and then to 1,300 mg for ages 9 through 18, when bones are growing fastest. A cup of milk provides roughly 300 mg, so a child who drinks a few glasses of milk or eats yogurt and cheese regularly can meet the goal through food alone.
Children who avoid dairy, whether due to lactose intolerance, allergies, or preference, often fall short. Fortified plant milks, calcium-set tofu, and fortified orange juice can help close the gap. When diet alone isn’t enough, a calcium supplement paired with vitamin D (which the body needs to absorb calcium) is a practical solution. One case report involving a toddler highlights why dosing matters: a child given excessive calcium and vitamin D gummy vitamins over several weeks developed dangerously high calcium levels, required intensive care, and had a prolonged hospital stay. Stick to the recommended amounts.
Vitamins A, C, and E
National health surveys consistently identify vitamins A, C, and E as nutrients that American children underConsume. Vitamin A supports vision and immune function. Vitamin C helps wound healing and acts as an antioxidant, and both vitamin C and zinc play roles in shortening the duration and severity of respiratory infections like the common cold. Vitamin E protects cells from damage.
Most children who eat a varied diet with fruits, vegetables, and some healthy fats will get adequate amounts. But “varied diet” is doing a lot of heavy lifting in that sentence. If your child subsists mainly on chicken nuggets, crackers, and pasta, a children’s multivitamin can serve as a reasonable safety net. One caution with vitamin A: there’s a meaningful difference between the plant-based form (found in carrots and sweet potatoes) and the preformed version found in supplements and liver. The tolerable upper limit for preformed vitamin A is 600 mcg for children under 3, rising to 900 mcg for ages 4 to 8. Exceeding these levels over time can cause toxicity, so check supplement labels carefully.
Choline and DHA for Brain Development
Choline plays a key role in the nervous system and normal brain development. It’s found in eggs, meat, fish, and some beans, but it’s another nutrient that surveys flag as underconsumed across the US population. Safe daily intake levels are generous: up to 1 gram for children ages 1 to 8 and up to 2 grams for ages 9 to 13.
DHA, an omega-3 fatty acid found in fatty fish like salmon and sardines, is important for brain and eye development, particularly in the early years. Children who rarely eat fish may benefit from a DHA supplement, often available as flavored liquid or chewable soft gels designed for kids.
B12: Essential for Plant-Based Diets
Vitamin B12 is found almost exclusively in animal products: meat, fish, eggs, and dairy. Children eating a standard diet typically get plenty. But for kids on vegan or mostly plant-based diets, B12 supplementation isn’t optional. Current guidelines for vegan infants recommend 5 micrograms per day starting around 4 to 6 months (the official dietary reference intake is lower, around 0.4 to 1.5 mcg, but experts recommend higher supplemental doses because the body absorbs only a fraction of each dose). Vegan children who don’t receive formula should be supplemented, even if the breastfeeding mother takes B12 herself, as an added layer of protection.
B12 deficiency can cause developmental delays, fatigue, and neurological problems that may not be immediately obvious. Fortified plant milks and nutritional yeast contribute some B12, but a dedicated supplement is the most reliable approach for plant-based families.
Multivitamin or Individual Supplements?
For most children eating a reasonably balanced diet, a standard children’s multivitamin acts as nutritional insurance, covering small gaps without providing excessive amounts of any one nutrient. If your child has a specific known deficiency or dietary restriction, individual supplements (like vitamin D drops for a breastfed infant, or B12 for a vegan child) allow more precise dosing.
When shopping for children’s vitamins, look for products that carry a third-party certification mark from organizations like NSF or USP. These certifications mean the product has been tested to confirm that what’s on the label is actually in the bottle, that no harmful contaminants are present, and that no undeclared ingredients have been added. The supplement industry isn’t tightly regulated, so these seals offer a meaningful layer of quality assurance.
Why Gummy Vitamins Need Extra Caution
Gummy vitamins are popular with kids for obvious reasons: they taste like candy. That’s also the risk. Children who find the bottle may eat handfuls, and gummy formulations often contain fat-soluble vitamins (A, D, E, K) that accumulate in the body rather than being flushed out. Store all supplements well out of reach, ideally in a locked cabinet, and treat them as you would any medication. If your child does consume a large number of gummy vitamins, contact poison control immediately.
Gummies also tend to contain added sugars, and some brands leave out iron entirely because it tastes metallic and discolors the gummy. If iron is a priority for your child, check the label carefully or opt for a chewable tablet formulation instead.