How much vitamin D is enough?

The very high levels of vitamin D that are often recommended by doctors and testing laboratories — and can be achieved only by taking supplements — are unnecessary and could be harmful, an expert committee says. It also concludes that calcium supplements are not needed.


The group said most people have adequate amounts of vitamin D in their blood supplied by their diets and natural sources like sunshine.

It is not clear how or why the claims for high vitamin D levels started, medical experts say. First there were two studies, which turned out to be incorrect, that said people needed 30 nanograms of vitamin D per milliliter of blood, the upper end of what the committee says is a normal range. They were followed by articles and claims and books saying much higher levels — 40 to 50 nanograms or even higher — were needed.

After reviewing the data, the committee concluded that the evidence for the benefits of high levels of vitamin D was “inconsistent and/or conflicting and did not demonstrate causality.”

I take 2,000 units of vitamin D a day, and get more in other supplements. Several doctors have looked at this and approved. I'll continue until I hear otherwise.