341 Vitamin D for Breastfeeding [19 Oct 2015]

Human breastmilk is known to be extremely low in vitamin D, so supplementation of 400 IU vitamin D is recommended for exclusively breastfed babies in Canada and the USA. But is this an inherent flaw in mother’s milk or an inadequate dietary recommendation of the vitamin for the mother? A randomized controlled trial recently published in the prestigious journal Pediatrics set out to answer that question.

The study started with 334 mother-infant pairs who were exclusively breastfeeding. In Group 1 both mother and infant were given 400 IU of vitamin D; in Groups 2 and 3 the mother was given 2,400 or 6,400 IU respectively and the infants none. Blood levels were tested at baseline, 4 months and 7 months. Interestingly the 2,400 IU group was stopped by the ethics committee after 4 months because too many of the infants were still D deficient. At the end of the study the infants from Group 3 had D levels equal to those in Group 1 who were supplemented with 400 IU.

The study concludes:

“Maternal vitamin D supplementation with 6400 IU/day safely supplies breast milk with adequate vitamin D to satisfy her nursing infant’s requirement and offers an alternate strategy to direct infant supplementation.”

Maternal supplementation has the added benefit of ensuring the mother has adequate D levels too.

I previously wrote about vitamin D supplementation during pregnancy [#160], referring to a study that found that its highest dosage (4,000 IU) was still insufficient to prevent the baby from being born with a D deficiency. I earlier wrote [#117] about cases of infantile rickets misdiagnosed as child abuse where babies with broken bones are taken into custody and the parents charged with abuse.

This study shows that the Canadian RDA for vitamin D at 600 IU for both pregnancy and lactation is an order of magnitude (10X) too small. The upper limit is set at 4,000 IU, and warns of possible adverse effects beyond that. Is there really evidence for this concern? In the Discussion section of this study the authors state:

“...during the past decade [in] several studies…involving several thousand patients… not a single adverse event has been attributed to vitamin D supplementation at the doses ranging from 2000 to 6400 IU/day".

Government organizations like Health Canada have been slowly raising the recommended levels of vitamin D as evidence mounts. This well-designed study should nudge this movement along another notch.

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.