From the Guidelines
Breastfed infants should receive a vitamin D supplement of 400 IU per day starting within the first few days of life and continuing until they are getting adequate vitamin D from other dietary sources, typically around 12 months of age. The supplement comes as drops that can be given directly into the baby's mouth or mixed with a small amount of expressed breast milk. While breast milk is the ideal food for infants, it typically contains low levels of vitamin D (about 25 IU per liter), which is insufficient to meet an infant's needs 1. Vitamin D is crucial for calcium absorption and bone development, and deficiency can lead to rickets, a condition causing soft, weak bones. Even if the breastfeeding mother takes vitamin D supplements herself, the amount transferred through breast milk usually remains inadequate unless she takes very high doses, such as 6400 IU of vitamin D 1. The supplement should be continued until the infant is consuming at least 1 liter of vitamin D-fortified formula or cow's milk daily or eating foods rich in vitamin D. Regular exposure to sunlight is not recommended as a source of vitamin D for infants due to skin cancer risks.
Some key points to consider:
- The American Academy of Pediatrics recommends vitamin D supplementation with 400 IU/day for all infants and children 1
- Breast milk contains low levels of vitamin D, making supplementation necessary for breastfed infants 1
- The supplement should be given directly to the infant, rather than relying on the mother's vitamin D intake, unless she is taking very high doses 1
- The recommended daily allowance for vitamin D for those aged 1 to 70 years is 600 IU/day, but breastfed infants should start with 400 IU/day 1
From the Research
Vitamin D Supplementation for Breastfed Infants
- The prevalence of vitamin D deficiency (VDD) in breastfed infants varies widely, ranging from 0.6% to 91.1% 2.
- Breastfed infants are at risk of VDD due to low vitamin D content in breast milk, restricted sunlight exposure, and limited dietary sources of vitamin D 2.
- The recommended intake of vitamin D for lactating mothers to optimize their vitamin D status and breast milk is 200-2,000 IU/day, but there is a lack of consensus 2.
- Direct infant supplementation is a currently available option to support vitamin D status in breastfed infants, with a recommended dose of 200-1,200 IU/day 2.
- Most international guidelines recommend that exclusively or partially breastfed infants be supplemented with 400 IU/day of vitamin D during their first year of life 2.
Effectiveness of Vitamin D Supplementation
- Vitamin D supplementation given to infants at 400 IU/day may increase 25-OH vitamin D levels and reduce the incidence of vitamin D insufficiency 3.
- Vitamin D supplementation given to lactating mothers may increase infant 25-OH vitamin D levels, reduce the incidence of vitamin D insufficiency and deficiency, and prevent biochemical rickets 3.
- Maternal vitamin D supplementation with at least 4000 IU/day can lead to adequate serum vitamin D levels in breastfed infants 4.
- Family Medicine clinicians are knowledgeable about current recommendations for vitamin D supplementation in breastfeeding infants and prefer maternal or infant supplementation over infant supplementation alone 5.
Alternative Supplementation Strategies
- Maternal postpartum (M-PP) or infant intermittent (I-INT) vitamin D supplementation may be plausible substitutes for routine daily infant vitamin D supplementation, but evidence is limited 6.
- M-PP supplementation resulted in modestly lower infant 25(OH)D compared to direct infant daily supplementation, but recent trials found similar infant 25(OH)D levels 6.
- I-INT supplementation had contradictory findings, and meta-analysis was limited by variable quality of data and inconsistent reporting of safety outcomes 6.