Vitamin B3 (Niacin)

Requirements:

• RDA:
  
  13 - 18 mg.
  15 mg. pregnancy
  18 mg. lactation
• Daily Optimal Intake:
  
  100 mg. (niacin and amide forms mixed)

Supplement Forms:

• Do not use time released niacin - some cases of fulminant hepatitis have been reported with this form
• Inositol hexa-nicotinate (contains 6 molecules of niacin and 1 molecule of inositol) - it does not cause flushing and does not appear hepatotoxic
• Niacin and niacinamide forms are available either separately or together
• Niacin is recommended for circulatory problems and lowering triglycerides and cholesterol

Food Sources:

• Beef 3 oz. (3.9 mg.)
• Beef kidney 3 oz. (9 mg.)
• Beef liver 3 oz. (14 mg.)
• Brewer's yeast 1 Tbl. (3 mg.)
• Brown rice 1/4 cup (2.5 mg.)
• Chicken, light 3 oz. (10 mg.)
• Chicken liver 3 oz. (3.8 mg.)
• Cod 3 oz. (2.5 mg.)
• Halibut 3 oz. (7 mg.)
• Peanuts 1/4 cup (6 mg.)
• Salmon steak 3 oz. (8 mg.)
• Sunflower seeds 1/4 cup (2.4 mg.)
• Swordfish 3 oz. (8.5 mg.)
• Tuna, canned 3 oz. (11 mg.)

Signs and Symptoms of Deficiency:

• Dementia including irritability, headaches, and insomnia mental confusion, hallucinations, amnesia, and severe depression
• Dermatitis including inflamed tongue and mouth
• Diarrhea

Causes of Deficiency:

• Alcoholism
• Corn not processed with lime
• High leucine

Adverse Effects and Toxicity:

• Caution when taking > 1 gm. per day:
  
  Liver enzymes should be monitored during niacin therapy - if elevated, cut back on dosage
  Nausea is first sign of toxicity with both niacin and niacinamide
• Flushing with niacin, so best taken with food
• Gastritis
• Increases uric acid levels
• Reactivates peptic ulcers

Contraindications:

• Niacin:
  
  Do not use with peptic ulcer disease, gout, elevated liver enzymes or liver disease
• Niacinamide:
  
  High doses should be given with caution in patients with diabetes and hypoglycemia

Drug/Nutrient Interactions:

• Postural hypotension may result from concomitant use of vitamin B3 and vasoactive drugs, including some medications for hypertension
• Rhabdomyolysis may result from concomitant use of vitamin B3 and HMG-CoA reductase inhibitors

Biochemical Functions:

• Coenzyme for dehydrogenases which are responsible for many biochemical reactions in the body, i.e., alcohol dehydrogenase, utilizing carbohydrates, proteins, and fats
• Involved in tryptophan and serotonin metabolism
• Niacin lowers cholesterol and triglyceride levels
• Required for pentose phosphate shunt pathway, a method of synthesizing ribose
• Required for NAD which is needed for redox reactions in glycolysis and Kreb's cycle during oxidative phosphorylation
• Required for the production of NADPH which is needed for synthesis of steroids and fatty acids

Clinical Indications:

• Atherosclerosis
• Attention deficit disorder - niacinamide
• Depression - niacinamide
• Diabetes mellitus
• Dysmenorrhea
• Headaches
• Hypothyroidism
• Impotence
• Memory loss
• Multiple sclerosis
• Osteoarthritis - niacinamide
• PMS
• Psoriatic arthritis
• Rheumatoid arthritis
• Alcoholism - niacinamide
• Anxiety
• Bell's palsy
• Hypercholesterolemia - niacin
• Hyperglycemia - niacin and chromium together
• Hyperlipidemia - niacin
• Hypoglycemia - niacinamide
• Insomnia
• May prevent loss of pancreatic beta cells in early stages of type I diabetes - niacinamide
• Migraine - must use at the beginning of the headache
• Raynaud's syndrome
• Schizophrenia
• Smoking cessation
• Trigeminal neuralgia

Copyright 1998 - 2008 by L. Vicky Crouse, ND and James S. Reiley, ND. All rights reserved (ISSN 1527-0661).