According to the Centers of Disease Control and Prevention (CDC), "Breast milk alone does not provide infants with an adequate intake of vitamin D. Most breastfed infants are able to synthesize additional vitamin D through routine sunlight exposure. However, published reports of cases of vitamin D deficiency rickets among breastfed infants in the United States caused researchers to take another look at whether all breastfed infants were getting adequate vitamin D." "Vitamin D deficiency rickets among breastfed infants is rare, but it can occur if an infant does not receive additional vitamin D from a vitamin supplement or from adequate exposure to sunlight. A number of factors decrease the amount of vitamin D a person will synthesize from sunlight. These factors include:
- Living at high latitudes (closer to the polar regions), particularly during winter months
- Air quality conditions: high levels of air pollution
- Weather conditions: dense cloud covering
- The degree to which clothing covers the skin
- Use of sunscreen
- Skin pigmentation: darker skin types
- Furthermore, there exists a major public health effort to decrease the risk of skin cancer by encouraging people to limit their sunlight exposure"
"There are 2 forms of vitamin D: D2 (ergocalciferol, synthesized by plants) and D3 (cholecalciferol, synthesized by mammals). The main source of vitamin D for humans is vitamin D3 through its synthesis in the skin" when exposed to ultraviolet light. "Historically, the main source of vitamin D has been via synthesis in the skin from cholesterol after exposure to UV-B light. Full-body exposure during summer months for 10 to 15 minutes in an adult with lighter pigmentation will generate between 10000 and 20000 IU of vitamin D3 within 24 hours; individuals with darker pigmentation require 5 to 10 times more exposure to generate similar amounts of vitamin D3." Vitamin D3 which is derived from fish "has greater efficacy in raising" vitamin D levels. It is the supplement of choice over vitamin D2.
"In a lactating mother supplemented with 400 IU/day of vitamin D, the vitamin D content of her milk ranges from <25 to 78 IU/L." Even if a mother takes a vitamin D supplement and her infant drinks a liter of breastmilk a day, this is far less than the 400IU recommended daily for infants. For a woman to produce the recommended amount of vitamin D in her breastmilk, she will have to consume 6400 IU/day of vitamin D supplements. "Although vitamin D concentrations can be increased in milk of lactating women by using large vitamin D supplements, such high-dose supplementation studies in lactating women must be validated and demonstrated to be safe in larger, more representative populations of women across the United States. Recommendations to universally supplement breastfeeding mothers with high-dose vitamin D cannot be made at this time. Therefore, supplements given to the infant are necessary."
Vitamin D supplementation is recommended because "in adults, new evidence suggests that vitamin D plays a vital role in maintaining innate immunity and has been implicated in the prevention of certain disease states including infection, autoimmune diseases (multiple sclerosis, rheumatoid arthritis), some forms of cancer (breast, ovarian, colorectal, prostate), and type 2 diabetes mellitus. Results from prospective observational studies also suggest that vitamin D supplements in infancy and early childhood may decrease the incidence of type 1 diabetes mellitus."
Despite the recommendations by the AAP, a study published in the journal Pediatrics, titled, "Adherence to Vitamin D Recommendations Among US Infants," found that "most US infants are not consuming adequate amounts of vitamin D according to the 2008 AAP recommendation. Pediatricians and health care providers should encourage parents of infants who are either breastfed or consuming <1 L/day of infant formula to give their infants an oral vitamin D supplement." I don't find this particularly surprising since many message boards that I have been reading have threads full of mothers saying that their Pediatricians have told them that it "wasn't necessary."
I plan on supplementing my baby with vitamin D especially since I will not be exposing him to much sunlight during his first six months of life. I remember that with my first baby, it was difficult in the beginning to get him to take his vitamin drop and I wasn't always that consistent with it. After researching this topic, I am going to have to make sure that I am more diligent with the vitamins and also be more diligent with myself getting enough calcium and vitamin D.