Why children and adults need vitamin D

Children need vitamin D for bone growth and development. So do babies developing in the womb. Vitamin D helps us absorb calcium.

Serious vitamin D deficiency in children can cause rickets, delayed motor development, muscle weakness, aches and pains, and fractures.

Vitamin D deficiency in adults has been linked to osteomalacia, osteoporosis, some cancers, heart disease and diabetes.

If women don’t get enough vitamin D during pregnancy, their children are at greater risk of developing rickets later in childhood. This risk is reduced if children get enough vitamin D after birth.

Vitamin D and sunlight

Children need sunlight on their skin for their bodies to make vitamin D. They get most of their vitamin D this way.

Scientists aren’t sure exactly how much sun children in Australia need for good levels of vitamin D. But we do know that the amount of sun your child needs depends on your location in Australia and the time of year.

It also depends a bit on your skin colour. People with very dark skin need 3-6 times more sun to make vitamin D than light-skinned people.

How much sun do children need to make vitamin D?

Here’s a guide to how much sun your child needs to make vitamin D, without putting your child’s skin at risk of sun damage.

Brisbane and Darwin
Right through the year, a few minutes most days of the week should be enough.

Canberra, Perth and Sydney:

• In June and July, 2-3 hours per week should be enough.
• In summer, a few minutes most days of the week should be enough.

Adelaide, Hobart and Melbourne

• From May to August, 2-3 hours per week should be enough.
• In summer, a few minutes most days of the week should be enough.

Children with dark skin living in Adelaide, Hobart or Melbourne in winter might not get enough vitamin D from the sun alone. It’s a good idea to ask your GP about whether your child also needs vitamin D supplements.

Be sun smart
No matter where you live in Australia, be careful about how much sun children get on their skin. Too much sun can lead to sunburn, skin damage and even skin cancer. This is why it’s important to use sun protection.

During summer, especially between 10 am and 4 pm, make sure your child stays safe in the sun with sunscreen, a hat, sunglasses, clothing that keeps the sun off, and access to plenty of shade.

To get more information and advice about how much sun is right for your child, speak with your GP.

Vitamin D and food

Most children won’t get enough vitamin D from food alone. But foods rich in vitamin D can add to the vitamin D your child gets from sunshine.

Foods naturally rich in vitamin D include:

• fatty fish (salmon, herring, mackerel and sardines)
• liver
• egg yolks
• mushrooms grown outdoors or in UV light.

Some foods have vitamin D added to them. These include some:

• breakfast cereals
• low-fat dairy products
• margarines.

All infant formula contains vitamin D.

Exercise helps your child’s body make vitamin D. Your child can make the most of being out in the sun by doing some daily physical activity outside.

Vitamin D deficiency

Children might be at risk of vitamin D deficiency if they:

• have very dark skin
• keep all their skin covered
• spend most of their time indoors and don’t get much or any sun
• have a condition affecting the body’s vitamin D levels – for example, liver disease, kidney disease, coeliac disease or cystic fibrosis
• are taking medicines that can affect vitamin D levels
• have been breastfed for a long time and their breastfeeding mother has low vitamin D
• eat a vegan diet.

Treating vitamin D deficiency

Talk with your GP if you’re worried about your child’s vitamin D levels, or you’re pregnant and think you might have low vitamin D.

Your GP can order a blood test, which is the best way to check vitamin D levels.

For a mild vitamin D deficiency, your GP might say that you or your child should get a bit more sun.

For a severe vitamin D deficiency, your GP might say you or your child should take vitamin D supplements, as well as getting more sun.

If you or your child can’t get more sun, the GP might say that taking vitamin D supplements is the best thing to do. You might take a vitamin D supplement in one large, single dose, or you might take a supplement for several weeks or months.

You can also talk to a dietitian about vitamin D supplements.

Solariums, sometimes called sunbeds or tanning beds, should never be used as a way to improve vitamin D levels or to treat vitamin D deficiency. Most states have a ban on commercial solarium operators. Solariums can cause skin cancer.

Vitamin D, pregnancy and breastfeeding

A baby’s vitamin D levels go up during development in the womb and go down after birth until the baby starts getting vitamin D from sunlight along with diet.

Breastfeeding babies don’t get much vitamin D from breastmilk, because breastmilk doesn’t have much. And if breastfeeding mothers have low vitamin D, they might not pass on enough vitamin D to their babies.

It’s recommended that breastfed babies with at least one other risk factor for low vitamin D, like very dark skin, take a vitamin D supplement of 400 IU or 10 micrograms (μg) a day. It’s a good idea to talk with your GP if you think your baby is at risk of vitamin D deficiency.

Infant formula has higher levels of vitamin D, so formula-fed babies don’t usually need a supplement.

If you take too much vitamin D from supplements, it can lead to too much calcium in your blood. This can cause problems in many parts of the body, including the kidneys, blood vessels, heart and bones. Always check with your GP or dietitian before taking a supplement or giving a supplement to your child.