I have had many questions posed to me regarding supplementing with niacin. Ironically, it seems that physicians are beginning to acknowledge nutrient supplementation for their patients as real medicine. My question, however, is a simple one. Are niacin and niacinamide interchangeable with respect to dosage? While the latter has a higher tolerance before adverse side effects occur, does that mean that one needs to take more of it? In short, would a dosage of 50 mg of niacinamide replace 50 mg of niacin, or is there a conversion factor?
Niacin and niacinamide are generally referred to generically as niacin, but their forms and potential therapeutic benefits differ. Niacin or nicotinic acid is the form used as a cholesterol lowering agent, with or without other statin (cholesterol lowering) drugs, for the treatment of hyperlipidemia. A drug called Advicor is a combination of the statin drug Lovastatin and extended release niacin. In the past, these two compounds were administered as separate agents. Typical treatment doses of niacin are 1500-3000 mg/day, although benefits have been measured with as little as 100 mg/day. The response appears to be dose dependant, so basically more is better. Across the board, niacin has been shown to lower LDL, TG and total cholesterol levels while simultaneously raising HDL levels. Together with the cholesterol and LDL lowing benefits of Lovastatin, these improvements in blood lipids significantly reduce the risk of coronary artery disease (CAD) and stroke, by as much as 90 percent when compared to placebo groups. However, these benefits do not come without potential problems. Noted or potential side effects associated with high dose niacin supplementation are liver damage (hepatotoxicity), impaired glucose tolerance and flushing. While sustained release niacin is often used to minimize flushing (the most common side effect), it has been linked to a greater risk of hepatic toxicity. All of this underscores the inherent dangers of self medication and using supplements for medicinal purposes. A physician can make these recommendations as appropriate and ensure appropriate follow up to monitor possible adverse events and toxicity. On the horizon is research to minimize the hepatotoxic effects, possible by increased intake of methyl donors such as betaine, SAMe and vitamins B6 and folate. These avenues are being investigated due to the observed increase in urine and blood levels of homocysteine with high dose niacin supplementation.
The RDA for niacin is set at 16 mg/day of NE (niacin equivalents) for men and 14 mg/day of NE for women. The term NE is used since tryptophan can contribute to niacin synthesis. This is typically a 60 mg of tryptophan to 1 mg of niacin conversion but can be affected by many factors such as other nutrient levels, protein intake and turnover.
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