The importance of vitamin D

Updated July 12, 2018

Growing from a tender baby into a climbing, racing toddler requires healthy food, plenty of rest and some help from a very important nutrient: vitamin D. "A baby is born with vitamin D they have gotten from their mother, but the amount varies and is related to how much vitamin D the mother has in her body," says Dr. Steven Abrams, professor of paediatrics at the Dell Medical School at the University of Texas at Austin. Until his diet is varied enough to get adequate vitamin D from nutritional sources, your baby will probably need supplementation.

Because babies are forming bones rapidly during the first year of life, they need enough vitamin D so that they can absorb the calcium in the diet and form strong bones.

Dr. Steven Abrams -- Professor of paediatrics, Dell Medical School, University of Texas

Vitamin D basics

"Vitamin D allows a baby or anyone else to absorb calcium from the diet," says Dr. Abrams. "Insufficient intake may place [a baby] at risk for a condition called rickets, in which weak bones lead to fractures and other bone problems." Rickets can also be passed along through genetics. Untreated, rickets can cause bone pain as well as stunted growth and development. That's a scary picture, but a baby who is nurtured and fed appropriately isn't at risk. Nutritional rickets is completely preventable.

Some babies are born with greater risk of vitamin D deficiency than others. Babies born to mothers who are obese or have dark skin are more likely to be deficient. Living in an area with little sunlight or having limited exposure to sunlight also puts mother and baby at risk of vitamin D deficiency.

Baby's vitamin D needs

All UK health departments recommend that infants aged 6 months and older receive 7 to 8.5 micrograms, or about 300 international units (IU), of vitamin D per day. Pregnant and breastfeeding women may get some vitamin D from their diets, but are advised to take supplements of 10 micrograms per day.

UK health departments don't give specific guidelines for infants younger than 6 months; however, the American Academy of Pediatrics (AAP) recommends that all breastfed babies receive at least 10 micrograms (400 IU) of vitamin D a day starting just after birth. "Babies usually get only a small amount of vitamin D from breast milk," explains Dr. Abrams. "They usually get more from infant formulas, and older infants get some from foods they eat that have vitamin D added to them."

No matter your baby's age, your paediatrician should help you determine her exact intake needs.

Giving your baby vitamin D

"Even a small amount of sun exposure provides vitamin D for an infant," says Dr. Abrams. "However, this is decreased by the use of sun block and also by winter weather. Infants with dark skin also receive less vitamin D from the sun than infants with lighter skin." So soaking up the rays would boost your baby's vitamin D production -- but because a baby's thin skin burns easily, your infant needs protection from the sun. That means infants must get the bulk of their vitamin D intake from diet and supplementation.

Very few foods naturally contain vitamin D: fatty fish, cheese and egg yolks are among them. For the most part, a child who is eating solid food will get his vitamin D from foods and drinks to which the nutrient has been added. One cup of fortified milk or orange juice will typically contain more than 2.5 micrograms (100 IU) of vitamin D. Yoghurt and cereal are commonly fortified as well.

Human milk only contains about 0.625 micrograms (25 IU) or less of vitamin D per litre, nowhere near the 10 micrograms (400 IU) recommended by the AAP. Formula is fortified with vitamin D, so a baby who is exclusively formula-fed should get enough of the nutrient. The AAP recommends that breastfed babies receive a daily supplement of 10 micrograms (400 IU) until they are drinking at least 1 litre of fortified milk or formula per day.

Until he's ready to be introduced to cows' milk -- typically not until his first birthday -- and solid foods, a breastfed baby will need vitamin supplements. These supplements usually come in the form of drops that you can give your baby orally.

On measurements

You'll often hear at least two forms of measurement used in relation to vitamin D: micrograms and international units, or IU. Just remember that one microgram equals 40 international units, so 10 micrograms equal 400 IU. Alternatively, to convert from IU to micrograms, multiply the amount in IU by 0.025, and to convert from micrograms to IU, divide the amount in micrograms by 0.025.

Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Cooking, travel and parenting are three of Kathryn Walsh's passions. She makes chicken nuggets during days nannying, whips up vegetarian feasts at night and road trips on weekends. Her work has appeared to The Syracuse Post-Standard and insider magazine. Walsh received a master's degree in journalism from Syracuse University.