For everybody who wants to follow up the most recent discussion about allergy promoting effects of vitamin D here is a short summary. The Harvard group basically wrote three articles that were immediately contradicted. The comment on the first article in JACI was by a NIH researcher
Several studies, including 2 conducted in cohorts from higher latitudes where infant vitamin D supplementation is quite prevalent, have shown that supplementation in infancy with vitamins is associated with increased incidence for allergies, whereas other experimental data suggest that vitamin D could contribute to allergy.
The second article in Thorax was written by a British researcher
The enthusiastic editorial … may have left some readers with the impression that a single cause of the rise in asthma, multiple sclerosis, inflammatory bowel disease and type 1 diabetes in the West has now been discovered, namely vitamin Ddeficiency, and that primary prevention of asthma and autoimmune disease is just around the corner. Indeed, their bold conclusion portrays vitamin D supplementation as a likely panacea for many ills worldwide … I would argue therefore that the vitamin D story is, at present, rather more confused….
while I wrote on their most recent article
Together with other studies not mentioned in their review that are testing effects of different vitamin D preparations, cod liver oil, and supplemented margarine the current picture of a sensitization risk caused by vitamin D supplements is rather clear.
In the traditional publication system, the last word is always with the primary authors but with blogs the discussion can continue ;-)
I am quite happy that after years of ignorance (usually stage 1 of any new hypothesis), we have now reached stage 2 (controversial discussion). I already predict stage 3 (common sense) to become reality as soon as if we will have the first RCT results at hand.
It remains the question why there is such a different perception in the community. I can only speculate by pointing to an earlier NEJM book review on on Vitamania: Vitamins in American culture.
Here are examples for 2006/stage 1 intentionally ignoring VD effects on allergy: a NEJM review manages to talk about vitamin A, C, E but not D – and again NEJM who quotes beneficial effects on wheeze but ignores adverse effects on atopy.
To be fair there is already a transition to stage 3
The positive association between the other fat soluble vitamin, vitamin D and atopy is less surprising, as infant supplementation with vitamin D has previously been reported to be linked to higher rates of asthma and allergic rhinitis.