Vitamin D in Breast Milk

by Christina on July 14, 2016

I just came across this great post on KellyMom (love that site!) about Vitamin D in breast milk.


She shares this article from Pediatrics and an interesting interview with the lead author:

peds vit d article

In the study they randomized lactating women to a daily Vitamin D supplement of 400 IU/day, 2400 IU/day, or 6400 IU/day. They measured maternal and infant Vitamin D levels at baseline, 4 months and 7 months. They found that supplementing lactating mothers with 6400 IU/day of Vitamin D is safe and provides sufficient Vitamin D in breastmilk (similar to infant supplementation of 400 IU/day).

Here are some excerpts from the KellyMom interview the lead study author Dr. Bruce Hollis, PhD:

How much vitamin D does breastmilk usually contain? Why?

Human breastmilk is a very poor source of vitamin D, usually containing less than 50 IU per quart. This is why the AAP recommends all breastfed infants receive 400 IU per day vitamin D by supplement drops. This IS NOT A DEFECT IN BREAST MILK but a defect in the recommended amount of vitamin D the lactating mom should be taking. If a mom takes 6400 IU per day, she will supply her nursing infant with plenty of vitamin D thru her milk and will not need to give her infant drops.

If a breastfeeding mother knows that her vitamin D blood level is “normal”  does that mean her milk will contain enough vitamin D?

NO! The 25(OH)D in your blood is not a good reflection of the amount of vitamin D that is available to pass into breastmilk. They are two different compounds. Since Vitamin D (rather than the active metabolite 25(OH)D) is the form that passes into a mother’s milk, the only sure way to know it is there is to take it every day. 

The Institute of Medicine has set the “upper limit” of recommended intake at 4000 IU. Is it safe for an adult to take 6400 IU?

The IOM setting a limit of 4,000 IU per day was subjective and not based on any trials. The Endocrine Society guidelines state that 10,000 IU per day is safe. In my own experience with our trial and several other trials in which I have been involved (involving tens of thousands of patients), not a SINGLE adverse event has been observed due to vitamin D intake. I personally take 6,000 IU per day and have for years, and my daughter just had a child and is taking 10,000 IU per day while lactating (going on a year now). Totally safe.

In this pregnancy I’ve been taking about 2000 IU/day of Vitamin D and plan to start upping this soon. Vitamin D supplementation is something I thought about quite a bit after my first son was born –– I wanted to make sure I was getting enough Vitamin D for him. I had increased my daily supplement to 5000 IU/day hoping a sufficient amount would pass on through my milk. Once he started solids we started putting Vitamin D drops in his morning oatmeal (in addition to DHA and probiotics).

Glad to see the research is showing this is effective!

{ 2 comments… read them below or add one }

Emily July 26, 2016 at 2:41 pm

So glad to see you posting again! MS4 out of michigan. Still trying to decide between EM and FM. Interested in work/life balance and starting a family. Worried I will miss long term care/preventative medicine if I go into EM, although I like the high energy. Would love some feedback on your decision for specialty. Do you find family medicine flexible? Hopefully everything is going well with the final days of your pregnancy (or first few days of new baby)!


Christina August 11, 2016 at 6:40 pm

See answer in the next post – sorry again for the delay! I’m excited for you and would love to hear more of your thoughts/decision making and help in any way I can!


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