Baby health

Vitamin D supplements

Most full-term babies should receive 400 IU of vitamin D a day. Here’s why

By Susan Spicer
Vitamin D supplements

You take your breastfed baby to the doctor for her first checkup and the doctor recommends that you give her a vitamin D supplement daily. This may be a bit confusing since, as Sharon Unger, spokesperson for the Canadian Paediatric Society (CPS), says, “breastmilk is a complete nutritional source for the full-term newborn.” So why the supplement? Here are answers to this and other questions you may have about vitamin D.

What is vitamin D?

Not technically a nutrient, vitamin D is a fat-soluble vitamin made by the body when sun shines on bare skin. It is present in substantial amounts in fatty fish, such as salmon, mackerel, tuna and sardines, but only in small amounts in certain other foods, so it’s difficult for people to get all they need without sun exposure. That’s why, in Canada, vitamin D is added to fortified milk and margarine.

Why do we need it?

Vitamin D helps the body absorb calcium. It is essential to the development of strong, healthy bones and teeth, and in the prevention of rickets, a disease in which the bones soften and become malformed. Recently, research has shown that vitamin D also contributes to healthy cell development, and a deficiency may be implicated in a host of other diseases, including diabetes, cancer, hypertension and several autoimmune diseases.

Do all babies need a supplement?


Over the past 30 years, several cases of rickets have been reported, primarily among First Nations children and children of Middle Eastern descent. This data, along with the new evidence about the importance of vitamin D, prompted the CPS, Health Canada and the Dietitians of Canada to make the recommendation that all full-term babies receive 400 international units (IU) of vitamin D a day. Different amounts may be required for babies who are premature or whose mothers have a vitamin D deficiency, and for those who live north of 55° latitude (about where Edmonton is), have darker skin or aren’t regularly exposed to sunlight.

Isn’t there vitamin D is breastmilk?

Yes, but according to the CPS, vitamin D deficiency is widespread in Canada, so pregnant and lactating women may not have adequate stores for themselves and their babies. That’s not a reason not to breastfeed; it just means that a host of factors may be limiting the synthesis of vitamin D for many of us.

Can’t my baby and I get vitamin D from the sun?

Most experts advise that infants under six months of age receive no exposure to the sun due to the risk of skin cancer. After that, babies should be protected with sunscreen — between 30 and 60 SPF — when exposed to the sun. Thus, it is not possible for babies to get vitamin D through sun exposure. For adults, studies have shown that five to 30 minutes of sun exposure to the face, arms, legs or back (without sunscreen) between 10 a.m. and 3 p.m. twice a week allows the body to synthesize adequate vitamin D. Other factors affect exposure levels, including darkness of skin, use of sunscreen (which blocks the ultraviolet rays that allow vitamin D synthesis), protective clothing and environmental factors, such as smog and even shade. “A woman who wears a head or face covering and has darker skin is not going to have the same levels as someone in the same city who is fair-skinned and works outside,” says Jen Peddlesden, professional liaison leader with La Leche League Canada in Chestermere, Alta.


In her view, the blanket recommendation is designed to protect everyone because there are so many individual factors at play. According to Unger, the evidence for supplementing all breastfed babies with vitamin D is very good. Women should talk to their doctors about how much vitamin D supplementation is appropriate for themselves and their babies.

How long should babies receive the supplement?

Until they get enough from foods, such as fortified cow’s milk. The current recommendation from CPS is that babies be exclusively breastfed for the first six months and that breastfeeding continue alongside complementary foods for two years and beyond. Your doctor will help you determine when to stop the supplement.

Can I boost my stores by taking a supplement rather than giving it to my baby?

According to the CPS, low levels of vitamin D in human milk “can be corrected by either supplementing mothers with relatively large doses of vitamin D during pregnancy and lactation or by supplementing infants.” Your doctor can advise which is appropriate for you.


Does the recommendation apply to formula-fed babies?

Vitamin D is added to formula. However, the CPS recommends that some formula-fed babies, including those in northern communities, be given 400 IU between October and April.

This article was originally published on Sep 20, 2002

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