Dr. Rhonda Patrick

All of them were associated with a lower dementia risk.

Specifically, using calcium vitamin D was associated with a 44% lower risk of dementia.

And using vitamin D3 was associated with a 37% lower risk of dementia.

And then using vitamin D2, which is the plant version, was actually associated with a 50% lower risk of dementia.

Using combined forms of vitamin D was associated with a 50% lower risk.

So I think here in concluding thoughts, overall, not only the findings of this study, but the other studies that I talked about really do give strong support to this idea that everyone should probably be supplementing with at least some vitamin D to make sure they're avoiding deficiency.

And as I mentioned earlier, deficiency is a widespread problem in the United States.

Up to 70% of people are either deficient or insufficient.

So getting a simple blood test is one of the best things you can do.

Measure your 25-hydroxy vitamin D levels.

This is the precursor to the active steroid hormone, 125-hydroxy vitamin D. And you want to have your 25-hydroxy vitamin D levels between 30 to 60 nanograms per milliliter is a great, I would say, level to have your vitamin D levels.

You don't really want to go above 80 nanograms per milliliter.

Then you start getting into a pretty high range.

Most people can take a supplement in the range of 2,000 to 4,000 IUs a day, depending at where your blood levels are at, and keep their vitamin D levels within that 40 to 60 range.

So it's good to kind of do an annual vitamin D blood test just to make sure you're not taking too much or to make sure that you're actually taking enough to raise your levels into that sweet spot.

And lastly, I just want to mention how vitamin D can support brain health.

So vitamin D can enhance the removal of amyloid beta.

This is a protein that's linked to Alzheimer's disease by promoting its efflux from the brain.

Now, I mentioned in that study, it was a randomized controlled trial.

And people that were giving an 800 IUs of vitamin D a day, people that already had Alzheimer's disease, it lowered their amyloid beta plaque burden.