A study in the August edition of the Journal of Clinical Investigation suggests that a form of vitamin B3, niacinamide, increased by 1000 times the ability of immune cells to kill MRSA. Niacin, or nicotinic acid, does not have this effect. Niacinamide in doses greater than 3 grams per day has the potential for serious liver disease, but does not have the flushing effect or cholesterol lowering effects of niacin. Neither a normal diet nor multivitamin pills have anywhere near the dosage needed for this effect.
Niacinamide works by turning on antimicrobial genes that increase the ability of immune cells to kill bacteria. White blood cells, called polys or polymorphonuclear cells, have been shown to have this effect in test tubes and in animals, but human studies are still needed to confirm that high dose niacinamide works in clinical MRSA infections. Nonetheless, it is something to consider in some patients who have MRSA infections.