Vitamin D is mostly harmless. Sure, it can cause toxicity (mainly hypercalcaemia), but usually at megadose levels of around 60 capsules per day.
Vitamin C is also mostly harmless. My parents, advised by the medical zeitgeist when I was a child, gave us one citrus-flavoured tablet every day during winter.
And extracted fish oils are mostly harmless, except of course to the extractees: the fish.
Another thing these three supplements have in common is that they are all wildly successful products of health marketing. Marketing that uses ordinary doctors to amplify the message…doctors like you and me.
Arthur Dent (upon reading the description of planet Earth in The Hitchhiker’s Guide to the Galaxy): “Is that all it’s got to say? Harmless! One word?”
Ford Prefect: “I managed to transmit a new entry off to the editor. He had to trim it a bit, but it’s still an improvement.”
Arthur: “And what does it say now?”
Ford: “Mostly harmless.”
As highlighted recently the US has seen almost a tenfold increase of vitamin D sales in the last decade compared to the previous. Yet a recent meta-analysis of 33 randomised trials showed that vitamin D or calcium supplementation has no effect on the incidence of fractures.
After years of venerating the “D”, it seems the vitamin is more often a marker associated with an illness rather than its cure. Continue reading