Four yrs ago
at age 67 I was diagnosed with PV, put on Hydrea and Eliquis. I also have phlebotomies about every 3-4 months. Despite this medication most of my blood counts usually are slightly out of range.
Interestingly enough while recently reviewing all of my blood test results, I noticed that in the past 4 yrs the one time all my blood counts were in the normal range (of course while continuing to take above mentioned meds) was when I went out of my way to add vitamin d and c (as well as my usual multivitamin) to my daily regimen because several members of my household contracted Covid and I was trying to prevent getting it. That is the only thing I did differently. Mentioned this to my hematologist and she said there was no relationship. I am not as convinced as she is…

Doctors don't know everything. When I told my doctor about my fatigue he said it had nothing to do with my MPN yet everything I read of first systems is fatigue.

I have taken Omega 3’s for many years, long before I transitioned from ET to PV and my Hematocrit became an issue.

I have not seen the relationship you describe, and I take my supplements with the knowledge and consent of my hematologist.