Should My Child Take Vitamin D?

Most (75%) of U.S. adults are taking a vitamin supplement, but is this necessary for children and adolescents? As fall approaches and the weather cools, your family may not be getting much sun exposure, making getting enough vitamin D difficult. Parents who have experienced a broken bone in the family can appreciate the importance of vitamin D and calcium for bone repair.

Many parents are committed to getting their children enough vital nutrients through a healthy diet, but others may have picky eaters and wonder if a dietary supplement makes sense to fill in the gaps. It is difficult to know which vitamins are lacking, and parents must be careful to avoid accidental overdoses. Parents of young children who have broken a bone may also wonder if their child is getting enough calcium, especially children with lactose intolerance. Does it make sense to supplement with vitamin D year-round? And how can parents estimate average daily calcium intake?

It turns out that bone fractures are extremely common, especially in the upper extremities, and one study found that children with ADHD might be at twice the risk of a fracture.

Efforts to improve diet and activity have real implications for bone strength as children grow. In a study of children with fractures, two-thirds of the children with a low-energy fracture were found to have vitamin D insufficiency and half had a calcium insufficiency. Channeling my tendency to be self-critical into a more productive path (research), I made a point to evaluate the top dietary insufficiencies among kids and identify ways to build important nutrients into a busy grab-and-go schedule.

The connection between calcium, sunlight, and strong bones

One of the earliest hormones made by all life forms exposed to sunlight, vitamin D plays an important role in bone metabolism and other cellular functions. An association between sun exposure and rickets (soft and weak bones) was noticed in 1889 — children in industrialized countries were at higher risk than those in less developed countries. The solution? Sunbathing. This is because vitamin D is important for calcium regulation, and it must be synthesized by the skin through a chemical reaction that is triggered by exposure to ultraviolet light from the sun (UVB rays), best achieved when the sun is high in the sky.

But how many of us are running around with our backs, arms, and legs exposed to full sunlight for 15 minutes daily around noon? Not likely in the winter, and even during the summer typically only while at the beach or pool. When the sun moves low across the sky, as in northern latitudes during the winter (above and below 35°N and S), not enough UVB gets through the atmosphere to produce pre-vitamin D3 in the skin. Having darker skin can reduce the penetration of UVB rays by 50-fold, and sunscreen with a sun protection factor (SPF) as low as 8 can nearly eliminate UVB penetration. In other words, it is not necessarily your fault for getting too little sunlight. There are times of the year, and locations on the planet, when this is just hard to do. (Find your latitude here.)

Vitamin D, calcium, and bone health

Bone is a matrix of cells that is not static — it undergoes regular remodeling throughout life, allowing bones to grow and the body to get the calcium it needs from storehouses in the skeleton. Vitamin D is connected to bone health because it plays an important role in calcium regulation but it also plays a role in cell signaling within the immune system.

Calcium is important not only for bone growth but for cellular functions as well, such as muscle contraction.

These observations connecting sunlight to bone health eventually led to vitamin D and calcium-fortified foods, such as milk, bread, hot dogs (and even beer).

Does my child need a vitamin D supplement?

Vitamin D usage among adults has increased substantially since the pandemic, however, parents may be unaware that many children are also lacking sufficient vitamin D. A study among adolescents in Boston found that one in four were vitamin D deficient (≤15 ng/mL), and nearly half were low (≤20 ng/mL). A quarter of the children were lower in the winter than in the summer.

How much vitamin D should my child take?

The Institute of Medicine recommends taking a supplement providing 600 IUs of vitamin D for people younger than 70. The safe upper limit is 2000 to 4000 IUs per day. Most vitamin supplements contain 2000 IUs of vitamin D, but a multivitamin might contain 1000 IUs.

Toxicity is possible as vitamin D, as well as vitamins A, E, and K, are fat-soluble vitamins, which means excess amounts above what your body needs are not excreted in the urine.

How much calcium is needed daily?

A child between 9 and 18 years of age needs 1300 mg of calcium each day, which means about 4 tall (8-ounce) glasses of milk. However, most adolescents, especially girls, are not getting enough calcium each day, and many children do not drink that much milk or have a milk allergy. Other non-dairy sources of calcium include salmon, hard cheeses, sardines, almonds, and leafy green vegetables.

Creative ways to build calcium into the typical day

Adolescents rarely eat three meals a day, but most have two or more snacks a day. Being intentional about snack options provides a good chance to boost essential nutrients. This is where taking a supplement for vitamin D might be helpful, too.

For those who have a milk allergy, sheep or goat’s milk products, or calcium-fortified juices may be tolerable. For example, Manchego — made from sheep’s milk —provides 300 mg of calcium per ounce (a typical block of Manchego is 8 ounces).

For children and teens on the go, breakfast bars, drinks, and powders also offer balanced nutrition, especially if you can take a minute to scan the label for lower-sugar, lower-sodium options. Getting 10-30 minutes of midday sun several times a week will help increase vitamin D synthesis and mobilize the calcium for bone remodeling.