It makes you wonder how much of what we accept as "normal" afternoon brain fog or tech burnout is actually just our biology reacting to this massive behavioral shift and lack of natural light.

1. Yes, vitamin D actually controls a lot of bodily functions it’s very easily set aside as not a “main” factor when in reality it actually controls a lot

2. This study was done on women in Denmark only which isn’t a great study subject considering Denmark doesn’t get a lot of sun to begin with so most of these women would already start at very low levels

3. This doesn’t directly correlate to women of color because WOC need higher dosage of vitamin D than white women do. The general range of “good” level of vitamin D that doctors tend to use is related to studies results gotten from white people when in reality brown and black people need way more for their range to be at a normal place.

If there were a connection then I would wager that there are more significant factors, since I have seen or heard of no evidence to assume those in sunnier climates have better verbal and visual memory.

The results of this study seem to show no significant correlation, anyhow.

At any rate their main marker for intelligence showed an impressive p=90%, so whatever cognitive effects were present they've not made them any smarter (at 10).

Maybe it's the high dose vitamin, maybe it's because one cohort was skewed one way on the socioeconomic spectrum, maybe it's something else entirely. More evidence would be needed imo to confirm Vitamin D3 has a direct contributor to cognitive performance as the research portrayed.