Comment by zamalek

I'm surprised that metastudies are inconsistent. Vit D and O-3 probably do have a large effect in a deficient populace (so, like, Seattle or landlocked areas respectively). Metastudies should be good at mitigating that (but I guess you can choose the studies that coincide with the outcome you want).

Either way, the conclusion to this whole debate is incredibly simple: get a blood panel done and go from there - it might not even be one of these that ails you.