Several pediatric societies along with the IOM have recommended infants get 400 IU of vitamin D daily to fulfill their vitamin D needs. The basis of this recommendation is to achieve 25(OH)D levels of 20 ng/ml. However, to date, there is actually limited data on whether 400 IU achieves this level. Furthermore, there is limited data on the 25(OH)D levels achieved by a variety of doses for infants.
A new randomized controlled trial carried out by Professor Sina Gallo and colleagues has attempted to fill these very gaps in research.
The researchers randomized 132 infants at one month of age to take either 400, 800, 1200 or 1600 IU/day for eleven months. They wanted to see which regimens ensured 97.5% of the infants achieved thresholds of 20 ng/ml and 30 ng/ml at three months of age and twelve months of age.
At three months of age, here is what the researchers found:
- In the 400 IU/day group, 55% achieved a level of over 30 ng/ml and 97% achieved a level of over 20 ng/ml.
- In the 800 IU/day group, 81% achieved a level of over 30 ng/ml and 97% achieved a level of over 20 ng/ml.
- In the 1200 IU/day group, 92% achieved a level of over 30 ng/ml and 96% achieved a level of over 20 ng/ml.
- In the 1600 IU/day group, 100% achieved a level of over 30 ng/ml.
At three months of age, the researchers chose to discontinue the 1600 IU/day arm. The researchers measured 25(OH)D with three different assays. Using an enzyme immunoassay, the 1600 IU/day group had mean levels of about 120 ng/ml, which is higher than what is often cited as the normal range of 30-100 ng/ml. So the researchers chose to place these babies on 400 IU for the remainder of the trial.
At 6, 9 and 12 months measurements, lower and lower percentages of babies met the 30 ng/ml threshold. This was expected as the babies grew and weighed more as they got older. However, no matter the dosage, 98% of the infants still met the 20 ng/ml threshold at 6, 9 and 12 months.
This research confirms the IOMs recommendation in that 400 IU will achieve 97.5% of babies less than one year old will achieve levels of 20 ng/ml. The researchers note, however, that if you want to achieve the Endocrine Society’s recommendation of at least 30 ng/ml, the 400 IU dose does not suffice for many babies over the course of their first year of life.
While IOM guidelines only recommend levels over 20 ng/ml for the time being, their recommendations do not preclude that guidelines may rise in years to come, perhaps to 30 ng/ml or higher. This randomized controlled trial has shown that doses of 400-1200 IU/day do not ensure 97.5% of infants achieve 30 ng/ml, raising issue the difficulties in making a population-based recommendation. Any step higher, like the 1600 IU/day used in this trial, and levels become too high for the first three months.
This highlights the need for more tailored recommendations for babies in the future. There will be a need for population-wide recommendations for very young infants and different recommendations for infants when they start getting a little older. For example, there may be a need for a recommendation for infants 0-6 months old and yet another for infants 7-12 months old.
Currently, the Endocrine Society recommends babies need 400-1000 IU of vitamin D/day. The Vitamin D Council recommends 1000 IU/day for babies weighing 0-25 lbs, which means that by these guidelines, most all babies up to one year of age require 1000 IU/day.
Vitamin D during pregnancy and early childhood is a complicated subject, so please be sure to read our page “Vitamin D during pregnancy and breastfeeding” for more information on requirements.