Why children need vitamin D
Children need vitamin D for bone growth and development. Vitamin D helps us absorb calcium.
Serious vitamin D deficiency can cause rickets. Vitamin D deficiency has also been linked to osteoporosis, some cancers, heart disease and diabetes.
Babies still developing in the uterus also need vitamin D. If women don’t get enough vitamin D during pregnancy, their children might develop neonatal hypocalcaemia (not enough calcium in the blood) or rickets later in childhood.
How children can get vitamin D
Sunlight
When sun – specifically UVB radiation – shines on our skin, our bodies make vitamin D. We get about 80% of our vitamin D this way. The Cancer Council recommends that:
- In summer, fair-skinned people can get enough vitamin D from just a few minutes of sun on hands, arms and face every day.
- In winter in Victoria and South Australia, 2-3 hours of sun a week will provide enough vitamin D.
- In winter in Tasmania, more than 2-3 hours of sun a week might be needed (according to recent research).
- In winter elsewhere in Australia, a few minutes a day will provide enough vitamin D.
Note: recommendations aside, there is no conclusive Australian or New Zealand data on how much UVB exposure is needed for children to maintain good levels of Vitamin D.
Too much time in the sun can cause sunburn, skin conditions and even skin cancer. During summer, staying out of the sun altogether between 10 am and 3 pm will help your child stay safe in the sun. The World Health Organisation also has recommendations for avoiding skin cancer based on a UV index.
Diet
Most children won’t get enough vitamin D from food alone. Vitamin D-rich foods can supplement the vitamin D your child gets from sunshine.
Foods naturally containing vitamin D include:
- fatty fish (North Sea salmon, herring, mackerel and sardines)
- liver
- egg yolks.
Some foods don’t naturally contain vitamin D, but have vitamin D added to them. These ‘vitamin D-fortified’ foods include some margarines and some milks (including fortified baby formula milk).
You can also take vitamin D supplements.
Vitamin D deficiency
Children might be at risk of vitamin D deficiency if they:
- need to keep all their skin covered (for example, for cultural reasons)
- have an illness that keeps them indoors
- use sunscreen in winter in one of the southern states (those living in a hotter state such as Queensland or the Northern Territory still need sunscreen in winter)
- have a physical or intellectual disability. A Melbourne study found that vitamin D deficiency was high among children with physical and intellectual disabilities. This might be because these children spend more time indoors. It might also be that they have a condition that reduces absorption of vitamin D (such as coeliac disease or cystic fibrosis)
- have darker skin. In these children, more sunlight is needed to produce the same levels of vitamin D that fair-skinned people produce. People with dark skin who also wear a veil have quite a high risk of vitamin D deficiency
- have been breastfed for a long time, are dark skinned and have a mother whose vitamin D is low.
Signs of vitamin D deficiency include:
- rickets (bone deformities)
- delayed motor development
- muscle weakness, aches and pains
- fractures.
Treating vitamin D deficiency
Ask your GP to do a blood test if you’re worried your child might not be getting enough vitamin D, or if you’re pregnant and think you have low vitamin D. A blood test is the best way to check your levels.
If your child has dark skin and does not get enough sun, or if your child can’t go in the sun for cultural reasons or because of a skin condition, talk to your doctor about taking supplements.
For mild deficiencies:
- Make sure that your child gets enough sun.
- Give your child foods that are high in vitamin D or are fortified with vitamin D. If you are breastfeeding and are vitamin D deficient, consider supplementing your breastfeeds with fortified formula.
If you or your child has a severe deficiency, your doctor will put you on a course of large doses of vitamin D.
Solariums are not recommended as way to improve vitamin D levels or treat vitamin D deficiency. Solariums can cause skin cancer.
Vitamin D, pregnancy and breastfeeding
An baby’s vitamin D stores increase during pregnancy and decline after birth until the baby starts getting vitamin D from sunlight or fortified formula. If pregnant women have low levels of vitamin D, they can pass the deficiency on to their children.
Generally, breastmilk is not a rich source of vitamin D. If the mother has low vitamin D while breastfeeding, it can be difficult for the baby to get enough of the vitamin.
Cases of rickets are rising in Australia, especially among children with dark skins. This is because dark-skinned women – particularly those who wear veils – have been found to have a high risk of vitamin D deficiency, which is passed on to their newborn children.
Breastfed children of dark-skinned women are at an increased risk of vitamin D deficiency and rickets. For this reason, researchers suggest that these children take vitamin D supplements until they are at least 12 months old.
