Dr. Rhonda Patrick

And this brings us to APOE4.

So I mentioned earlier, APOE4 is the biggest genetic risk factor for Alzheimer's disease.

25% of the population carries at least one allele.

Having one allele can increase the risk of dementia and Alzheimer's disease by twofold.

Having two copies of that allele can increase the risk up to tenfold.

So it's really important for people to understand that if they have one of these alleles, that they really need to try to do everything they can within their lifestyle to lower their dementia risk.

And so people that had ApoE4 that supplemented with vitamin D did reduce their incidence of dementia by around 33%.

And among non-carriers, vitamin D reduced the incidence of dementia by 47%, a little bit higher, which is not surprising.

And supplementing with vitamin D wasn't enough to outweigh the effects of carrying one or two copies of ApoE4.

These participants still had a 16% greater risk of dementia than non-carriers, even non-carriers who didn't use vitamin D.

The same was true for another risk factor, having mild cognitive impairment, which elevated dementia incidence by nearly 400% compared to people that had normal cognitive function, even in the presence of vitamin D supplementation.

So in other words, if you have an APOE4 allele or if you had mild cognitive impairment at the baseline level,

then you had a tremendously higher risk of getting dementia and Alzheimer's disease.

However, the vitamin D supplementation did still help.

It just didn't help as much as someone that was healthy and had normal cognitive function and was a non-carrier at the start of this study.

Okay, so let's dig a little bit deeper.

Participants with mild cognitive impairment who didn't supplement with vitamin D had more than a 600% increase in dementia risk compared to the adults with normal cognitive function, even those who didn't use vitamin D. So in other words, I just mentioned that people that had mild cognitive impairment

had a 400% higher risk of having dementia compared to people that had normal cognitive function at the beginning of the trial.

But that was only if they supplemented with vitamin D. People that didn't supplement with vitamin D had a 600% higher risk of developing dementia if they started with mild cognitive impairment.

It also didn't matter what form vitamin D was used.