Social and environmental considerations. Vitamin D deficiency is prevalent in sun-rich environments as well.8 This is most likely attributable to cultural and economic barriers to buying and eating natural and fortified foods rich in vitamin D. Mothers who constantly wear clothing that covers most of the body (such as veils and long-sleeved garments) are at higher risk for deficiency, and so are their infants.10 Clothing that covers most of the body leads to deficiency similar to that caused by dark pigmentation.

How to achieve appropriate vitamin D levels

Lactation. On average, vitamin D levels in breast milk are 22 IU/L in vitamin D-sufficient mothers. This can increase to nearly 70 IU/L if the mother supplements with 200 IU of vitamin D per day.5 This is still significantly less than the required levels of formula fortified with vitamin D.

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In a study, vitamin D supplementation increased to 2,000 IU/day resulted in little improvement in the circulating levels of the infant.6 In studies in which supplementation was dramatically increased to between 4,000 to 6,400 IU/day, the bioavailability of vitamin D rose to a more acceptable level of 115 nmol/L in the mother’s breast milk.6,8

No official guideline exists for maternal supplementation during breastfeeding. Based on recent data, maternal vitamin D intake of >4,000 IU/day appears to be safe and provides sufficient vitamin D to ensure adequate nutritional status for the mother and the nursing infant.3,6

Women can also achieve adequate vitamin D levels to supplement their breast milk through diet and sun exposure. Foods rich in vitamin D include such oily fish as salmon, mackerel, and sardines; cod-liver oil; liver and other organ meats; and egg yolks. Sunlight accounts for roughly 90% of most people’s vitamin D production, but the risk of skin cancer raises concerns.

Direct infant supplementation. The surest way to achieve sufficient vitamin D levels in infants is by administering direct supplementation. AAP guidelines recommend starting when the infant is aged 2 months. According to the AAP, direct supplementation is favored because infants younger than age 6 months should have no direct contact with the sun and should always be fully protected with sunscreen to prevent unwanted exposure thereafter. Offering protection against the risk of skin cancer dramatically hampers the infants’ ability to create vitamin D, thus necessitating a secondary source.

Bottom line

Vitamin D is known to be more important than ever for protection against chronic illnesses. PCPs must remind mothers of the importance of breastfeeding and finding a way to achieve adequate vitamin D levels in infants. Current guidelines suggest that direct supplementation for infants is the best method, however studies of maternal supplementation have shown promising results. In the end, the goal is to provide infants with the healthiest possible start by achieving adequate vitamin D concentrations.

Ms. Delcour works as a board-certified nurse practitioner at a family practice in Olympia, Wash.


1. Rajakumar K. Vitamin D, cod-liver oil, sunlight, and rickets: a historical perspective. Pediatrics. 2003;112:e132-e135.

2. Ziegler EE, Hollis BW, Nelson SE, Jeter JM. Vitamin D deficiency in breastfed infants in Iowa. Pediatrics. 2006;118:603-610.

3. Kovacs CS. Vitamin D in pregnancy and lactation: maternal, fetal, and neonatal outcomes from human and animal studies. Am J Clin Nutr. 2008;88:520S-528S.

4. Misra M, Pacaud D, Petryk A, et al. Vitamin D deficiency in children and its management: review of current knowledge and recommendations. Pediatrics. 2008;122:398-417.

5. Taylor SN, Wagner CL, Hollis BW. Vitamin D supplementation during lactation to support infant and mother. J Am Coll Nutr. 2008;27:690-701.

6. Wagner CL, Greer FR; American Academy of Pediatrics Section on Breastfeeding; American Academy of Pediatrics Committee on Nutrition. Prevention of rickets and vitamin D deficiency in infants, children, and adolescents. Pediatrics. 2008;122:1142-1152.

7. Perrine CG, Sharma AJ, Jefferds ME, et al. Adherence to vitamin D recommendations among US infants. Pediatrics. 2010;125:627-632.

8. Hollis BW, Wagner CL. Vitamin D requirements during lactation: high-dose maternal supplementation as therapy to prevent hypovitaminosis D for both the mother and the nursing infant. Am J Clin Nutr. 2004;80(6 Suppl):1752S-1758S. 

9. Merewood A, Mehta SD, Grossman X, et al. Widespread vitamin D deficiency in urban Massachusetts newborns and their mothers. Pediatrics. 2010;125:640-647.

10. Dijkstra SH, van Beek A, Janssen JW, et al. High prevalence of vitamin D deficiency in newborn infants of high-risk mothers. Arch Dis Child. 2007;92:750-753.

All electronic documents accessed March 15, 2011