Ray Peat said:"Caffeine, vitamin E, and niacinamide are known to reduce the activity of heme oxygenase. Sodium bicarbonate taken before strenuous exercise reduces the expression of heme oxygenase and improves endurance. A severe deficiency of vitamin B1 increases the expression of heme oxygenase. Testosterone can restore a youthful balance between heme and heme oxygenase, increasing heme, decreasing heme oxygenase. In newborn animals, D-penicillamine(an amino acid that is fairly safe to use as a heavy metal chelator) has lowered heme oxygenase. Apigenin, a chemical in guavas and oranges, with anti-inflammatory effects, inhibits heme oxygenase. Avoiding exposure to toxic heavy metals, and being in brightly lighted environments as much as possible, well help to avoid unnecessary carbon monoxide formation. "
Source: Hormones, energy, aging, and endogenous carbon dioxide newsletter.