Dr. Rhonda Patrick

A lot of times they'll look at genes that are also involved in SNPs that basically make the conversion of either vitamin D precursor into D3 or D3 into 25-hydroxyvitamin D or into the active steroid hormone, which is 125-hydroxyvitamin D.

So you're not looking at vitamin D levels at all.

You're looking at just the SNPs and you know if they have it, they have low vitamin D. People randomly have these genes and it's not like there's no health status.

So these Mendelian randomization studies have found that people that can't convert

into the precursor, the 25-hydroxyvitamin D, which is usually what's measured.

It's the most stable form of vitamin D in the body.

They have a higher all-cause mortality if they can't do it.

So people that don't have it have a lower all-cause mortality.

They have a higher respiratory-related mortality.

They have a higher cancer-related mortality.

They also are more likely to get multiple sclerosis.

This has all been done with Mendelian randomization.

And so it really does hammer home the importance of measuring your vitamin D levels and being very proactive about that.

I mean, you can get it done anywhere.

Your doctor will do it.

You ask them to do it, you know.

So supplementation-wise, typically, if you don't have one of those SNPs, for the most part, taking 1,000 IUs of vitamin D will raise blood levels by around 5 nanograms per milliliter.

So let's say you're deficient, you're 20 nanograms per milliliter, and you want to get to 40.

You're going to need at least 4,000 IUs.

If we look at the literature, the scientific literature, it is extremely hard to get like hypercalcemia, which would be the major concern with really high levels of vitamin D3 supplementation.