Protocols › Vitamin D

Vitamin D for breastfed babies

Goal: What trials and pediatric guidance used to keep vitamin D levels from falling too low in breastfed babies.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Updated 3 Nov 2026
Dose

400 IU (10 µg) a day, given to the baby.[1][2]

Form

Vitamin D given to the baby. When mothers took 4000 IU a day or more instead, their babies reached blood levels similar to those with 400 IU given to the baby.[1]

When to take

The American Academy of Pediatrics advises starting soon after birth. It advises continuing until the baby is weaned and drinks at least 1000 mL a day of fortified formula or whole milk.[2]

How long

Trials lasted up to 6 months.[1]

What studies found

A 2020 Cochrane review of 19 trials with 2837 mothers and babies: 400 IU a day raised the baby's 25(OH)D by about 23 nmol/L. It made a level below 50 nmol/L 43% less common.[1] The evidence was of low certainty. The review could not tell whether it prevents rickets or improves bone.[1]

Ask a doctor first

Breast milk has little vitamin D: less than 0.6 to 2.0 µg per liter (25 to 78 IU).[2] The upper limit for babies is 1000 IU (25 µg) a day under 6 months and 1500 IU (38 µg) at 7 to 12 months.[2]

Trials gave breastfeeding mothers from 400 IU to more than 4000 IU a day. The adult upper limit is 4000 IU.[1][2] Ask a pediatrician or pharmacist before giving a baby any supplement, or before a breastfeeding mother takes a high dose.

References

  1. Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health. Tan ML, Abrams SA, Osborn DA Cochrane Database Syst Rev, 2020. PMID 33305822
  2. Vitamin D: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov