One of the best places for info on D is: www.vitamindcouncil.com
I use to have one of those Earl Mendell Vitamin Bibles...it helped me through periods when I need it most. Booked marked the site you recommend. Mendell said that Zinc was the Master mineral while E was the Master Vitamin of the body.
I don’t take A, but do E, C, probiotics, plant sterols, flax seed, fish oil, B12, and Coleagen. You have to be careful of the oil based vits building up in the blood stream. I do take the D3. It’s strange that when my husband takes the fish or flax seed oil his heart does a random double beat, scares the day lights out of him. We were trying to get his cholestrol down with out all the drugs which have so many muscle side effects. Diet doesn’t help much, it’s more hereditary.