A few weeks ago, I launched a series on vitamin D and health outcomes, starting with pregnancy and fertility. That wasn’t really the most obvious place to start (though I had my reasons for wanting to tackle those outcomes first, as I explained in the piece). The vast majority of the hype about vitamin D centers on other areas, with immunity being probably the most-touted outcome.
So today, we’re going to discuss that. Does vitamin D supplementation really help reduce the incidence or severity of Covid, as is often claimed? What about the flu or the common cold? I dove deep into the evidence to find out.
And of course a discussion of immunity would be incomplete without delving into autoimmunity, where there’s also a ton of hype when it comes to vitamin D. Could supplementation reduce or eliminate autoimmune symptoms, as many wellness-culture denizens argue?
Spoiler alert: vitamin D doesn’t really live up to the hype in these areas. Although a few studies have shown promising results for vitamin D supplementation in certain aspects of immunity and autoimmunity, overall the evidence is weak and the potential for bias significant.
Let’s dig into the data and you’ll see what I mean.
