Before this possible PV, my other PCP a DO advised some supplements in response to my health problems ie. cholesterol, and lack of energy, and those have helped with my energy and overall wellness feeling. I do my best to avoid pharmaceutical medications and try natural treatments.
My DO advised pharmaceutical-grade vitamins and they can be pricy.
The 3 major brands she referred me to were Metagenics, Designs for Life, and Orthomolecular. I was not successful with Orthomolecular staying in stock anywhere. My doc recommended getting as many of them as I could afford. She emphasized fish oil, coq10, and L-Carnitin 1000 mg (L-Carnitin for energy)but I only take 500mg daily. Also the regular vitamins Zinc 50, Calcium, and Vit D 5000 UI. I took several of these anyway but I didn't realize pharmaceutical grade was a higher quality, especially with fish oil.
I do not take a multivitamin... At one point I had a high iron reading but it came back down so that isn't a problem now but for me, I do not take iron.
I found metagenics and Designs for life on Amazon and other places.

I eat pretty healthy, mainly a huge salad with a side of protein. I try to stay away from starch and sugar. My protein is usually salmon burger, tuna, or tilapia however I will have a lean piece of red meat sliced up on my salad on occasion and I will indulge very rarely but do eat a sandwich out sometimes.
My research for PV nutrition says no abundant green leafy vegetables so that has me in a tizzy. I used romaine and leaf lettuce but have cut that 50% now by using cucumbers as the base for most of my salads. My research also says no cold water fish so that leaves tilapia and I guess catfish.
My research says nuts and berries but those can irritate diverticulitis so maybe I can work those in small amounts.
I take red yeast rice pharmaceutical grade for cholesterol so no grapefruit or grapefruit juice.
When my diagnosis is confirmed and if she decided to put me on meds Im sure we will have to re-evaluate my supplements.
This is just what I have done with my diet and trying to keep myself going however it's not meant as advice. I hope it helps with examples. I didn't know they made pharmaceutical-level vitamins.
Although there is an explanation about the green leafy veggies I don't understand it yet.