It's an age problem. My body needs magnesium, B-complex, Omega3, and I take a L-Arginine supplement to support nitric oxide production, (important for the process). Not all supplements are equal so I did a lot of searching on the web before buying. Since I'm only 3 years into the remission cycle I get a lot of labs done on a regular basis and the doc's check a lot of the things including vitamin levels.
You have to be careful with supplements, too much can be a bad thing.