Vitamin D for Breastfed Babies: Why It Is Recommended and What Parents Need to Know

Why breast milk alone is not enough vitamin D

Vitamin D is unusual among nutrients in that it is not reliably supplied by diet alone — the main human source is synthesis in the skin from sunlight exposure. Breast milk contains relatively little vitamin D, regardless of how well-nourished the breastfeeding parent is 1Ref 1American Academy of Pediatrics (2022).Where We Stand: Vitamin D & Iron Supplements for Babies.AAP recommendation of 400 IU vitamin D per day for breastfed infants starting shortly after birth; threshold of >27 oz/day formula for formula-fed babies not needing supplement; continuation until adequate vitamin D from diet. The skin synthesis route is not reliably available for infants because direct sun exposure in young babies is not recommended due to the risk of sunburn, and many families live at latitudes or in conditions where outdoor sun is seasonal or limited. Supplementation bridges this gap 2Ref 2Wagner CL, Greer FR; AAP Section on Breastfeeding; AAP Committee on Nutrition (2008).Prevention of Rickets and Vitamin D Deficiency in Infants, Children, and Adolescents.AAP clinical report establishing 400 IU/day vitamin D for all infants; rationale including low breast-milk vitamin D content, sun exposure limitations; rickets prevention; risk factors for deficiency including darker skin pigmentation and latitude.

The AAP recommendation: 400 IU per day

The AAP recommends that exclusively breastfed and partially breastfed infants receive supplements of 400 IU (10 micrograms) per day of vitamin D, starting shortly after birth 1Ref 1American Academy of Pediatrics (2022).Where We Stand: Vitamin D & Iron Supplements for Babies.AAP recommendation of 400 IU vitamin D per day for breastfed infants starting shortly after birth; threshold of >27 oz/day formula for formula-fed babies not needing supplement; continuation until adequate vitamin D from diet. This supplement should be continued until the baby is weaned and consuming more than 27 ounces per day of vitamin D-fortified formula — or, once older, is reliably getting adequate vitamin D from a combination of formula, vitamin D-fortified foods, and diet 1Ref 1American Academy of Pediatrics (2022).Where We Stand: Vitamin D & Iron Supplements for Babies.AAP recommendation of 400 IU vitamin D per day for breastfed infants starting shortly after birth; threshold of >27 oz/day formula for formula-fed babies not needing supplement; continuation until adequate vitamin D from diet. The 400 IU threshold was established in the AAP's 2008 clinical report to prevent rickets and address widespread deficiency, raising the prior recommendation from 200 IU 2Ref 2Wagner CL, Greer FR; AAP Section on Breastfeeding; AAP Committee on Nutrition (2008).Prevention of Rickets and Vitamin D Deficiency in Infants, Children, and Adolescents.AAP clinical report establishing 400 IU/day vitamin D for all infants; rationale including low breast-milk vitamin D content, sun exposure limitations; rickets prevention; risk factors for deficiency including darker skin pigmentation and latitude.

Who needs a supplement and who might not

• Exclusively breastfed babies and partially breastfed babies not yet receiving adequate formula need a supplement.
• Exclusively formula-fed babies taking the volume of formula that meets their nutritional needs generally get adequate vitamin D from the formula itself and do not need a separate supplement 1Ref 1American Academy of Pediatrics (2022).Where We Stand: Vitamin D & Iron Supplements for Babies.AAP recommendation of 400 IU vitamin D per day for breastfed infants starting shortly after birth; threshold of >27 oz/day formula for formula-fed babies not needing supplement; continuation until adequate vitamin D from diet.
• Babies transitioning to some solids around six months of age: the supplement is typically continued until the baby is reliably getting adequate vitamin D from other sources.

Some babies may have additional risk factors for low vitamin D: darker skin pigmentation (which affects skin synthesis efficiency), limited geographic or seasonal sun exposure, and certain medical conditions affecting absorption 2Ref 2Wagner CL, Greer FR; AAP Section on Breastfeeding; AAP Committee on Nutrition (2008).Prevention of Rickets and Vitamin D Deficiency in Infants, Children, and Adolescents.AAP clinical report establishing 400 IU/day vitamin D for all infants; rationale including low breast-milk vitamin D content, sun exposure limitations; rickets prevention; risk factors for deficiency including darker skin pigmentation and latitude. A pediatrician can note whether a baby has factors that make monitoring more important.

What the supplement looks like in practice

Infant vitamin D supplements are typically available as liquid drops — a very small volume, designed to be placed on a nipple or the breast before a feed, or given directly by dropper. Some combination products also contain other vitamins; isolated vitamin D drops are also widely available. The drops are generally well-tolerated. The baby's own pediatrician can confirm the appropriate product and amount at the first visit 1Ref 1American Academy of Pediatrics (2022).Where We Stand: Vitamin D & Iron Supplements for Babies.AAP recommendation of 400 IU vitamin D per day for breastfed infants starting shortly after birth; threshold of >27 oz/day formula for formula-fed babies not needing supplement; continuation until adequate vitamin D from diet.

What happens if a baby does not get enough vitamin D

Prolonged vitamin D deficiency in infancy and early childhood can lead to rickets — a condition where bones do not mineralize correctly, potentially leading to bowed legs, soft skull bones, and delayed fontanelle closure 2Ref 2Wagner CL, Greer FR; AAP Section on Breastfeeding; AAP Committee on Nutrition (2008).Prevention of Rickets and Vitamin D Deficiency in Infants, Children, and Adolescents.AAP clinical report establishing 400 IU/day vitamin D for all infants; rationale including low breast-milk vitamin D content, sun exposure limitations; rickets prevention; risk factors for deficiency including darker skin pigmentation and latitude. Rickets is largely preventable with adequate vitamin D intake. Mild deficiency without full-blown rickets is more common and may not have obvious symptoms. Routine supplementation in breastfed infants is one of the most straightforward and well-supported preventive measures in newborn care 2Ref 2Wagner CL, Greer FR; AAP Section on Breastfeeding; AAP Committee on Nutrition (2008).Prevention of Rickets and Vitamin D Deficiency in Infants, Children, and Adolescents.AAP clinical report establishing 400 IU/day vitamin D for all infants; rationale including low breast-milk vitamin D content, sun exposure limitations; rickets prevention; risk factors for deficiency including darker skin pigmentation and latitude.