Vitamin D is a fat soluble vitamin critical for musculoskeletal health. It is sometimes known as the “sunshine vitamin” because it is produced in the skin in response to natural sunlight. Vitamin D is unique from other vitamins because of it’s hormone-like function in the body. 


Vitamin D3 is metabolized in the liver and converted to 25 (OH)D which is then converted to 1,25 OHD = calcitriol, which is the active form of vitamin D. 

Dietary sources of vitamin D:

  • Fatty fish - salmon, sardines, fish eggs, fish liver 
  • Organ meats, esp. Liver
  • Egg yolks (3x higher if chickens are outdoors in sunlight)
  • Dairy products - whole milk from pastured cows OR fortified
    • Yogurt and cheese not always fortified
  • Animal fats of pastured animals 
    • Butter, lard, tallow if animal received adequate sunlight 
  • Fortified foods 
  • Mushrooms - small amounts of vitamin D2 if grown under UVb light 
  • However, diet is considered a poor source of vitamin D

Co-Factors of Vitamin D:

  1. Magnesium
  2. Vitamin A
  3. Vitamin K2
  4. Calcium
  5. Zinc 
  6. Boron 

These cofactors are needed in adequate amounts in order to utilize vitamin D more efficiently. 

Vitamin D is important for  regulating absorption of calcium and phosphorus, facilitating normal immune function, and development of bones and teeth, especially in young children. Vitamin D also plays a role in cancer prevention, depression, type 2 diabetes, cardiovascular disease, and multiple sclerosis. 


While vitamin D deficiency is often considered a 19th century disease, it is still fairly common in countries around the world, including in Australia and New Zealand. 


So how do you know if your child is deficient in Vitamin D? 


Common Signs and Symptoms of Vitamin D Deficiency: 

  • Being sick or getting frequent infections 
  • Fatigue and tiredness 
  • Mood disturbances
  • Bone and back pain 
  • Impaired wound healing 
  • Bone and hair loss
  • Muscle pain
  • In severe cases, osteomalacia occurs which is the softening of the bones and leads to rickets or bow legs 


Common Risk Factors for Vitamin D deficiency in Children:

  • Children with very dark skin - as melanin acts as a natural sunscreen blocking sunlight 
  • Not eating fish or dairy
  • Living far from the equator where there is little sun year-round
  • Always using sunscreen or always staying indoors 
  • Premature babies
  • Breastfed babies - as breastmilk does not contain much vitamin D, and is dependent on mother’s vitamin D status 


While the optimal level of vitamin D is highly debated, according to the recommended daily adequate intake (AI) of vitamin D in Australia, supplementing with 200 IU or 5 micrograms is appropriate for children. 


By: Anabelle Clebaner MS, RDN 




Brittany Darling
Tagged: Vitamin D