Vitamin D is sometimes called the sunshine vitamin, because the skin makes it in sunlight. So it surprises many parents in Jordan and the Gulf, where the sun shines most of the year, to hear that their child's vitamin D is low. It is a common finding.
What vitamin D does
Vitamin D helps the body absorb calcium and keep the right levels of calcium and phosphate in the blood. Children need it for bones and teeth to grow and develop normally, and it also plays a part in the immune system and in muscle function.
How common is low vitamin D here?
A nationally representative survey of 1,077 Jordanian children aged one to five, carried out in 2010, found that about one in five (19.8%) had vitamin D deficiency and more than half (56.5%) had levels below the sufficient range. Girls were more likely to be deficient than boys, and in cities, children of mothers with low vitamin D were more likely to be low themselves.
Why sun is not enough
- Time indoors. School, screens and air-conditioned homes keep children inside, and sunlight through a window does not make vitamin D.
- The hottest hours. The midday sun is when the skin makes the most vitamin D, and in summer it is also when it is too hot to play outside.
- Covered skin and sunscreen. Both reduce how much vitamin D the skin makes. Sunscreen is still important for longer time outdoors.
- Winter. In Amman and other high areas, cold weather and winter clothes mean little skin sees the sun for months.
- Darker skin. It makes less vitamin D for the same time in the sun.
- Food. Few foods contain much vitamin D, and many children don't eat the ones that do.
How much vitamin D do children need?
The NIH Office of Dietary Supplements recommends:
| Age | Vitamin D per day |
|---|---|
| Birth to 12 months | 10 µg (400 IU) |
| 1–13 years | 15 µg (600 IU) |
| 14–18 years | 15 µg (600 IU) |
This is the total from food, sunlight and supplements together. In the UK, the NHS advises a daily supplement of 10 µg for all children aged 1 to 4, all year round.
Where vitamin D comes from
- Oily fish such as salmon, sardines and mackerel.
- Egg yolks.
- Fortified foods: some milks, yogurts, breakfast cereals and juices. Check the label.
- Sunlight on bare skin, for short periods, with sunscreen for longer time outdoors.
- Supplements, when the doctor advises them.
Can a child have too much?
Yes. Too much vitamin D, almost always from taking too many supplements, can make a child unwell. The NIH sets upper limits for children of 63 µg (2,500 IU) a day at 1–3 years, 75 µg (3,000 IU) at 4–8 years and 100 µg (4,000 IU) at 9–18 years, from all sources. Stick to the dose on the pack, and count every product that contains vitamin D.
What low vitamin D can lead to
Over time, a lack of vitamin D means the body cannot absorb enough calcium. In children, a long-lasting deficiency can cause rickets, in which bones become soft, weak and misshapen. Low vitamin D is usually found with a blood test.
When to talk to your child's doctor
Talk to your child's doctor if your child spends little time outdoors, has darker skin, eats few vitamin D foods, or has bone pain, bowed legs, slow growth or muscle weakness. Ask before giving any vitamin D supplement, and tell the doctor about every product your child already takes. The doctor can decide whether a blood test is needed.