Vitamin D Supplementation for Breastfed Infants - Questions and Answers for Professionals

Q1: If breast milk is the "optimal food", how can it be deficient in vitamin D?

A: Breast milk is the optimal food for infants. However, since sunlight is the principal source of vitamin D for all humans, a dietary vitamin D supplement is recommended for all infants in Canada to correct for a lack of exposure to ultraviolet light. More information on breastfeeding is available in the document Nutrition for Healthy Term Infants.

Q2: Why is a population health approach taken when only a small minority of infants are at risk of rickets?

A: A population health approach to vitamin D supplementation is warranted because it is not practical nor cost-effective to screen all mothers and infants to determine whether they are vitamin D deficient or at risk for vitamin D deficiency. Vitamin D status of Canadians is influenced by multiple variables - a wide range of latitudes and thus sun exposure, consumption of milk, the major dietary source of vitamin D, varying degrees of skin pigmentation and adherence to sun protection recommendations. Also, new evidence suggests that in addition to vitamin D's role in the prevention of rickets, an optimal vitamin D status may play a role in the protection against the development of other chronic diseases.

Q3: Why is Health Canada recommending 10µg (400 IU) per day when the Dietary Reference Intakes (DRI) report states 5µg (200 IU) per day?

A: Although the DRI table recommends 5 µg (200 IU) per day, it is stated in the report that "at least 5 µg (200 IU) per day of vitamin D for children aged 0-6 months is recommended". It is mentioned in the DRI report that "10 µg (400 IU) per day would not be excessive for infants 0-1 year"*. Health Canada decided to stay with a level of 10 µg (400 IU) given the fact that: i) we live at a Northern latitude ii) rickets is still prevalent in Canada iii) babies have an increased growth velocity in that first year and iv) 10 µg (400 IU) is a safe level that has been recommended since 1967.

* Institute of Medicine Food and Nutrition Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Dietary reference intakes for calcium, phosphorous, magnesium, vitamin D, and fluoride, 1997

Q4: How long has vitamin D supplementation for infants been recommended in Canada?

A: Canadian health authorities have had a guideline for vitamin D supplementation since 1927*. From 1927 to 1966, a vitamin D supplement was recommended in the form of cod liver oil. Since 1967, a vitamin D supplement has been recommended at a level of 10 µg (400 IU) per day.

* The Canadian Mother's Book, Ottawa, 1927

Q5. What percentage of breastfed infants are currently being supplemented with vitamin D?

A: In the Canadian Community Health Survey (CCHS) 2.1 (data collected in 2002), 53% of breastfed babies were reported to have received a vitamin supplement containing vitamin D. However, data on the frequency and quantity was not collected.

Q6: Are there certain groups of infants more at risk than others for developing vitamin D deficiency rickets?

A: Yes, infants who are more at risk include infants living at Northern latitudes, those with darker skin, those who are exclusively breastfed and those born to mothers who are vitamin D deficient. Infants from Northern latitudes are at risk due to inadequate ultraviolet exposure to stimulate formation of vitamin D in the skin for a large portion of the year. Dark skinned infants have a higher risk of developing vitamin D deficiency rickets because they require longer exposure to sunlight to produce the same amount of vitamin D as light-skinned infants. Infants born to mothers who are vitamin D deficient are also at increased risk. Vitamin D deficiency in the mother may be due to avoidance of milk products, lack of vitamin D supplementation during pregnancy as well as limited sun exposure (due in part to increased use of sunscreens or extensive covering of skin (i.e women who wear a veil)).

Q7. If direct sun exposure is not recommended for infants and young children, does that mean that infants should not be taken outside?

A: No, Health Canada encourages parents and caregivers to take their infants outside but they should ensure that babies are protected from direct sun rays.

Q8. What other countries with similar latitudes recommend a vitamin D supplement for breastfed infants?

A: Other countries which recommend a vitamin D supplement of 10 µg (400 IU) per day include Germany, Sweden, Finland, the United Kingdom and the Netherlands.

*Zitterman A. Vitamin D in preventative medicine: are we ignoring the evidence? Brit J of Nutr 2003; 89:552-72.

Q9. What is the Tolerable Upper Limit for vitamin D in infants?

A: The tolerable upper limit (UL) for infants 0-1 years for vitamin D is set at 25 µg (1000 IU) per day. The UL is defined as the highest continuing daily intake of a nutrient that is likely to pose no risks of adverse health effects for almost all individuals. The UL was set based on a systematic risk assessment approach. In the case of vitamin D, for infants the critical adverse effect of excessive vitamin D intake was retarded linear growth, observed at vitamin D intakes of 45 -112.5 µg (1800- 4500 IU) per day. A level at which no adverse effect of vitamin D on linear growth was seen averaged 45 µg (1800 IU) per day, a level referred to as the No-observed-adverse-effect-level (NOAEL). An uncertainty factor of 1.8 was applied to the NOAEL to account for uncertainties in the data, resulting in the UL of 25 µg (1000 IU) for infants.

Q10: On average, how long does a healthy term infant's vitamin D store last?

A: Studies suggest that vitamin D stores are depleted within eight weeks of birth in breastfed infants who do not receive a vitamin D supplement and who are born to mothers with adequate vitamin D stores*. It is important for the mother to ensure adequate vitamin D intake during pregnancy by eating a healthy, well balanced diet according to Canada's Food Guide to Healthy Eating.

* Salle B et al. Perinatal metabolism of vitamin D. Am J of Clin Nutr 2000; 71: 1317S-24S.

Q11: When should the vitamin D supplement be started?

A: It is recommended that the vitamin D supplement be started at birth and continue until the baby's diet includes at least 10 µg (400 IU) per day of vitamin D from other dietary sources or until the breastfed infant reaches one year of age.

Q12: What is the vitamin D recommendation for babies over one year of age?

A: Babies over one year of age should have an intake of 5 µg (200 IU) of vitamin D, as recommended in the DRI report. A supplement may be recommended if the baby's diet does not contain 5 µg (200 IU) of vitamin D.

Q13: Is there a specific recommendation for Northern children?

A: At this time, the available evidence shows that 10 µg (400 IU) of vitamin D is the amount recommended for all babies living in Canada regardless of what part of the country they live in. However, Health Canada recognizes that there is a need for further surveillance and research related to vitamin D, particularly in this population.

Q14: Is a vitamin D supplement recommended for infants fed commercial breast milk substitutes?

A: Infants fed commercial breast milk substitutes do not need a vitamin D supplement because commercial breast milk substitutes are already fortified with vitamin D at a level of 2.5 µg (100 IU) /250 mL.

Q 15. How was this recommendation on vitamin D supplementation for breastfed infants developed and who was involved?

A: Advice and guidance was sought from a variety of experts and stakeholders. An internal Health Canada Internal Infant Feeding Working Group was created. The recommendation on vitamin D supplementation for breastfed infants is based on the advice of the Internal Infant Feeding Working Group and the Dietary Reference Intake Expert Advisory Committee. This document has also been reviewed by the following Canadian vitamin D experts (see list below).

The draft recommendation was also posted to Health Canada's website for a comment period. Interested parties were invited to participate in this comment period by completing a comment form. Sixty-one respondents sent in comments, representing over 337 reviewers. These comments were then reviewed by the Infant Feeding Working Group and the Experts in finalizing the recommendation and supporting materials.

Canadian vitamin D experts consulted:

Stephanie Atkinson, Ph.D. R.D. Professor, Department of Paediatrics, Faculty of Health Sciences, McMaster University.
Member of the Standing Committee for the Scientific Evaluation of the Dietary Reference Intakes (DRIs) and Chair of the Panel on Calcium and Related Nutrients.

Leanne Ward, MD Pediatric Endocrinologist, Children's Hospital of Eastern Ontario.
Principal Investigator for the Canadian Paediatric Society Surveillance Study on Vitamin D Deficiency Rickets (2002-2004).

Francis Glorieux, MD, Ph.D. Professor of Surgery, Pediatrics and Human Genetics, McGill University, Director of Research, Shriners Hospital for Children.
Bone metabolism disorders researcher and expert in vitamin D physiology