By Neil E. Levin, CCN, DANLA, NOW's Nutrition Education Manager
Please read this if you are concerned about niacin in multivitamins and B-complex vitamins. NOW Foods uses only flush free forms of niacin in its products, with the exception of a few formulas, including Niacin 500 mg, Niacin 500 mg Sustained Release, True Balance™, and Energy™.
There is a 20 mg per day recommended Daily Value (DV) of niacin from any source and in any form. The Tolerable Upper Intake Level (UL) for niacin is set at 35 mg per day, which is primarily based on one form of vitamin B3 (niacin itself, also called nicotinic acid) potentially causing an uncomfortable "niacin flush". 1 However, all forms of niacin are lumped together under this arbitrary upper limit, with no real scientific justification given for their inclusion. 2 Federal regulations also require that all forms of niacin be lumped together and primarily labeled as "Niacin", with the exact form(s) secondarily listed in parentheses. This understandably leads to a lot of confusion about the use and potential side effects of various forms of niacin.
It is well documented that niacinamide (nicotinamide) does not cause a niacin flush. 2,3 Nor does inositol hexanicotinate 4, sold commonly as "Flush Free Niacin" and utilized by many physicians as part of their cholesterol management programs. This means that these forms should probably not be (but are) included in the UL for niacin (nicotinic acid).
In many NOW products, including multivitamins and B-complex vitamins, only the flush-free forms niacinamide (nicotinamide) and inositol hexanicotinate are actually included in the formulas. A few formulas contain the co-enzyme form of niacin, called NAD or NAD(H) - in small amounts, and this form is also considered to be safe (it doesn't cause a niacin flush).
ChromeMate® is a unique form of biologically active niacin-bound chromium called chromium nicotinate or chromium polynicotinate that dramatically increases the effectiveness of chromium. 22, 23 NOW uses this form of chromium in several products, and it has a proven safety record. 24, 25 A serving of ChromeMate® provides 200 mcg of elemental chromium and 1.1 mg of niacin, a relatively low level supplying only 5.5% of the Daily Value.
Based on the references, it does not appear that the forms and amounts of niacin present in most NOW supplements would normally cause any significant adverse effects when used as directed on the labels, even when taking those forms of "Niacin" in potencies above the UL, such as B-50 caps or Adam™. Higher amounts than recommended on a product label should only be used as directed by a health professional, who should monitor the person for symptoms of toxicity that could occur at much higher levels. Adverse effects (other than the niacin flush) have occurred at relatively high doses of 1,500 mg/day for niacin and 3,000 mg/day for niacinamide, far above the 35 mg/day UL set for all forms of niacin. 5
The niacin flush consists of skin reddening, itching and/or burning starting 10 - 20 min after oral ingestion of the nutrient and lasting about 60 - 90 min. 3,6 Although most patients experience tolerance to the flush within a week 3,7, as many as 40% of patients started on nicotinic acid eventually discontinue therapy, even when started on sustained release formulations 3,8. The niacin flush can also be largely avoided by taking aspirin at least 30 minutes before the niacin, so those who take aspirin daily may be somewhat protected from this uncomfortable side effect even when taking true niacin. 3 There is some evidence that the risk of developing liver toxicity from very high doses of niacin could possibly be lowered by supplementing with a methyl donor, such as TMG (betaine), to prevent depletion of S-adenosylmethionine (SAM-e or SAMe). 26
All forms of niacin are not created equal from a scientific viewpoint, even though government scientists have apparently decreed otherwise. It is important for the needs of individual biochemistry and health that various forms of niacin are available in potencies above the UL, which was set largely for people to avoid the niacin flush, along with information on their safe use. 9-21
For detailed references, please contact NOW Foods.