Why vitamin D matters for your child, and what to do about low levels
Vitamin D is a vitamin that we make in our skin from the action of sunlight. Only a small amount comes from what we eat. Vitamin D helps keep bones and muscles strong and healthy, by helping the body absorb calcium and phosphate (minerals) from food.
Low vitamin D is very common, especially in families who are new to Australia and especially during winter, when there may not be enough sunshine to make enough vitamin D. Some things that make low vitamin D more likely include:
Many families have more than one of these factors at the same time, which is why checking vitamin D levels is a routine part of the first health check, and children and families may need to take vitamin D during the winter every year.
Low vitamin D can cause pain in the bones or muscles, tiredness, muscle cramps, and slower growth. Very low vitamin D can cause rickets, a condition where the bones are soft and can bend, causing "knock knees" or "bow legs." Rickets is more common in babies and young children. Very low vitamin D can sometimes cause low calcium levels in the body, which can cause muscle cramps, or even seizures (fits) in young children. These problems can be prevented or treated with the right care.
Contact your doctor if your child has muscle twitching or jerking movements or seems unusually unwell. This can be a sign of very low calcium linked to vitamin D deficiency and is easily treated when found early.
Low vitamin D is checked with a simple blood test. Your doctor will let you know the result and explain what it means for your child.
Treatment usually involves vitamin D drops or tablets, taken daily or as a larger dose, depending on your child's age and how low their level is. Your doctor will work out the right amount for your child.
Getting enough calcium is also important. Good sources include milk, cheese, yoghurt, and plant milks with added calcium.
Breastfed babies who have other risk factors should have daily vitamin D drops until they are at least 12 months old.
Safe sun exposure and outdoor play are the best natural sources of vitamin D. How much sun is helpful depends on skin colour:
In the cooler months (May to August), especially in southern parts of Australia, sunlight alone often isn't enough. Children with ongoing risk factors for low vitamin D may need a vitamin D supplement over winter.
Your child will usually have a follow-up blood test about 3 months after starting treatment, to check the vitamin D level has improved. If your family has recently arrived and it's coming into winter, your doctor may suggest checking again at the end of winter.
Your doctor will help you make a long term plan so you can manage low vitamin D for your family yourself, by taking vitamin D during the winter or through the year.