Breastmilk does have vitamin D. Low amounts of it that do not meet the RDA. Some call it “deficient”. This is misleading.
Vitamin D is actually a prohormone, not a vitamin. Our skin synthesizes it when it is exposed to sunlight. It was never intended to be absorbed through diet, therefore it is not passed through breastmilk in any substantial quantity. Or any milk, for that matter. Breastmilk is not “deficient” in vitamin D because it is not SUPPOSED to contain large amounts of D.
Our lifestyle is deficient in sunlight, and therefore our bodies are deficient in D. Because we avoid sunlight, live sedentary lives indoors and slather on sunscreen when we go outside, many people are D deficient. This can cause rickets which are weakened bones (vitamin D is needed by the body for the body to use calcium properly) as well as other health issues.
The body stores vitamin D , and when mom is pregnant she passes the vitamin D stores on to baby, so babies are born with enough D to last through the winter without much sunlight. If mom’s D deficient, baby will be born D deficient or with lower stores of D and will need vitamin D drops. (NOT multivitamin drops)
Whether you supplement with D depends on this:
1- Do you live in a climate that gets enough sunlight?
2- Do you regularly expose your baby to sunlight without a hat or sunscreen? Is it safe to do so? (in Florida, for example, it may be too easy for baby to get a sunburn. Or in very northern climates it may be too cold to expose baby to enough sunlight with enough skin being bare. (Sunlight through windows doesn’t work.)
3- Were you regularly exposed to sunlight throughout your pregnancy?
4- People with darker skin have a harder time with vitamin D synthesis than people with lighter skin, so this needs to be taken into account as well.
There are a variety of “Just D” drops for breastfeeding babies that do not have the additional vitamins commonly found in the often-prescribed multi-vitamins. Read the ingredients, as some of these still have unnecessary ingredients that your baby may be sensitive to.