Niacin, NAD, Vitamin B3, etc.
Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline.
Dec, 2022 –
I, Roc, just take niacin, vitamin B3. NAD+ and similar compounds are hydrolyzed by the acid in our stomachs, so the only thing absorbed from the intestine is niacin. And niacin is what is transported into the mitochondria, which is where it is useful and converted into NAD+. Science magazine published several years ago that older people are often deficient in niacin in their mitochondria, and that’s when I began supplementing with Niacin, vitamin B3, which is inexpensive and very useful as we age.
“The enzymes that are produced in the lining of your digestive tract need to break down NAD+ several times in order for it to be absorbed. Eventually nicotinamide (another form of niacin) is the end product of NAD+ digestion, which can be directly absorbed into the body.”
Reader was concerned that niacin can give a person a flush. To avoid this, “Flushing may be minimized by taking niacin with meals (or at bedtime with a low-fat snack), avoiding exacerbating factors (alcohol or hot beverages), and taking 325 mg of aspirin 30 minutes before niacin dosing.”
So taking a niacin supplement is likely to benefit energy and health as we age.
Dec 2021: We find that, despite systematic claims of overall changes in NAD+ levels with aging, the evidence to support such claims is very limited and often restricted to a single tissue or cell type. This is particularly true in humans.
Dec 2021: Best way to deal with Alzheimers is to prevent it. A diet with a relatively high amount of vitamin B3 from regular foods such as chicken, peanuts and tuna protects against Alzheimer’s disease.
Vitamin B3/Niacin supplementation dramatically and beneficially raises growth hormone levels for several hours. Pilot Study-Effects of Niacin Administration on FFAs-Free Fatty Acid & Growth Hormone in Obese Children Pediatr Obesity 9-21-2016.
Science 9 July 2021 pg 172 – Faulty microbiome bacteria deplete nicotinamide (vitamin B3) which causes ALS (amylotropic muscular dystrophy). Deficiency also causes other dementias like Alzheimers and Parkinsons. This is clear evidence of the value of B3 supplementation.
From Philip Lee Miller, MD www.antiaging.com California Age Management Institute: I am happy to have started this thread. I realize this is a very heated topic. I submitted the article from Dr. Berkmayer. It is indisputable that most significant molar production of ATP is produced through oxidative phosphorylation – the ETC. NADH is converted to NAD+ in complex 1. It is well known that NAD+ does not cross mitochondrial membranes. So all the NAD “precursors” such as NR and NMN as well as NAD+ do not penetrate the mitochondrial matrix. Intra-mitochondrial NAD and NADH must be produced de novo from salvage pathways.
From Roc Ordman, PhD: It has been reported in Science that NAD levels in humans decrease with age (ref). NAD is biosynthesized from vitamin B3 (niacin), which is safe when consumed up to 35 mg/day. Over that level, the only hazard is flushing. Excess niacin is excreted. I take 500mg/day with no ill effects. The RDA for adults is 16 mg/day of NEs for men and 14 mg/day of NEs for women. Recently, the median intake of preformed niacin from food in the United States was approximately 28 mg for men and 18 mg for women. So taking a niacin supplement is a safe, inexpensive and convenient way to maintain niacin levels. Other forms like NMN, NR, NADH, and NAD are likely to be a waste of money. Any study supporting their use should have a control using niacin instead. The dietary reference intake report of the National Library of Medicine describes metabolic transport and function of NAD, niacin, etc.
Absorption of nicotinic acid and nicotinamide from the stomach and the intestine is rapid (Bechgaard and Jespersen, 1977) and at low concentrations is mediated by sodium ion-dependent facilitated diffusion. At higher concentrations, passive diffusion predominates, with doses of 3 to 4 g of niacin almost completely absorbed (Bechgaard and Jespersen, 1977). Glycohydrolases in the liver and intestines catalyze the release of nicotinamide from NAD (Henderson and Gross, 1979). Nicotinamide is then transported to tissues to be used in synthesis of NAD when needed. Both forms of the vitamin enter cells by simple diffusion; however, both nicotinic acid and nicotinamide also enter erythrocytes by facilitated transport (Lan and Henderson, 1968).
Metabolism and Excretion
The niacin coenzymes NAD and NADP are synthesized in all tissues of the body from nicotinic acid or nicotinamide. Tissue concentrations of NAD appear to be regulated by the concentration of extracellular nicotinamide, which in turn is under hepatic control and is hormonally influenced. Hydrolysis of hepatic NAD allows the release of nicotinamide for transport to tissues that lack the ability to synthesize the NAD and NADP coenzymes from tryptophan. I
Excess niacin is methylated in the liver to N1-methyl-nicotinamide, which is excreted in the urine along with the 2- and 4-pyridone oxidation products of N1-methyl-nicotinamide. The two major excretion products are N1-methyl-nicotinamide and its pyridone derivative (Mrochek et al., 1976). The proportions differ somewhat depending on the amount and form of niacin ingested and the niacin status of the individual.
Adverse Effects
There is no evidence of adverse effects from the consumption of naturally occurring niacin in foods. Therefore, this review is limited to evidence concerning intake of niacin as a supplement, food fortificant, or pharmacological agent.
One report showed adverse effects after consumption of bagels to which 60 times the normal amount of niacin had been added inadvertently (CDC, 1983). Most of the data on the adverse effects of excess niacin intake are from studies and case reports involving patients with hyperlipidemia or other disorders who were treated with pharmacological preparations containing immediate-release nicotinic acid or slow- or sustained-release nicotinic acid. The Tolerable Upper Intake Level (UL) developed here applies to all forms of niacin added to foods or taken as supplements (e.g., immediate-release, slow or sustained-release nicotinic acid, and niacinamide [nicotinamide]). Adverse effects such as nausea, vomiting, and signs and symptoms of liver toxicity have been observed at nicotinamide intakes of 3,000 mg/day (Rader et al., 1992) compared with intakes of nicotinic acid of 1,500 mg/day (McKenney et al., 1994). The generic term niacin may be considered interchangeable with nicotinic acid. As described below, the critical adverse effect selected was flushing to the extent that it results in a change in the dosing pattern or withdrawal from treatment.
Vasodilatory Effects (Flushing). The term flushing covers a burning, tingling, and itching sensation as well as a reddened flush primarily on the face, arms, and chest. Flushing occurs in many patients treated with nicotinic acid therapeutically. It is often accompanied by pruritus, headaches, and increased intracranial blood flow (Miller and Hayes, 1982). Occasionally, it is accompanied by pain (Bean and Spies, 1940). Case reports and clinical trials have reported flushing effects at oral doses of 30 to 1,000 mg/day within 30 minutes to 6 weeks of the initial dose (CDC, 1983; Estep et al., 1977; Henkin et al., 1990; McKenney et al., 1994; Sebrell and Butler, 1938; Spies et al., 1938). Although flushing is a transient effect, it often results in patients deciding to withdraw from treatment.
