If you follow proper handling precautions you can safely make lower concentrations of sodium chlorite.
Sodium chlorite does not provide oxygen to the body. It provides oxidation.
If you take too much the side effects include diarrhea, vomiting and nausea. Skin contact with the concentrated solution (3 - 5%) can cause chemical burns to tissue. Long term use of higher doses can chelate essential minerals out of the body. You need to pay attention to diet to counter this.