Will supplementing iron help the blood hold more oxygen? what are the best supplements and what are the side effects. thanks nat.. freediver.

Not necessarily: Iron helps only if you have an iron-deficiency anemia, with a low hemoglobin count that rises if you replenish iron. If you have normal hemogloblin, iron supplements can only cause side effects (stomach pain, black stools, and worse if you overdose).

If you are deficient: If you are not iron-deficient or have an extra need (blood donor, if you are a man), all it will do is upset your stomach. If you are iron-deficient, you being a man need to find out why -- it's a bad ulcer or gut cancer until proved otherwise, and taking an iron supplement will mask this. If you load yourself with iron you don't need, you are asking for liver trouble, impotence, and more.