The importance of vitamin B3 (Niacin) has been made clear to the public since the early 1900’s. The start of the eighteenth century was a period where corn was the main source of food in a majority of American diets. The lack of variety in diet, coupled with inadequate intakes of niacin, resulted in a high rates of pellagra (especially in the southern states).  Pellagra is a disease state which results from a deficiency of niacin and protein in the diet. It is characterized by skin eruptions, digestive and nervous system disturbances, and eventual mental deterioration.
A niacin-rich diet is important. Although it can be produced in the body, amounts are not sufficient enough to prevent deficiencies and provide for critical metabolic processes in the body. Vitamin B3 is important for the conversion of caloric intakes from fat, proteins, and carbohydrates, into usable energy.
Niacin is the term that encompasses the three forms of Vitamin B3; nicotinic acid, nicotinamide and inositol hexaniacinate. These three forms produce two coenzymes which provide for over 50 metabolic reactions in the body:
Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are important hydrogen carriers that function in oxidation-reduction reactions. Their main importance is glycolysis, or the ability to assist our bodies in obtaining energy from glucose via the Krebs cycle and the electron transport chain. These compounds also assists us in the deamination of amino acids, fatty acid synthesis, and beta-oxidation of fatty acids which are all consumed in our diets.
It is important to note that our diets supply niacin in two separate ways:
- Preformed - conversion of Vitamin B3 from selected nuts, meat, and poultry sources
Niacin is a very stable vitamin and is rarely lost in any preparation method for cooking (e.g. excessive heat, oxygen).
|Food||Measure||Mg of niacin|
|Bakers yeast compressed||1 oz:28g||40.32|
|Peanut butter||1 cup:258g||35.32|
|Peanuts oil-roasted||1 cup:144g||20.56|
|Peanuts raw||1 cup:146g||17.62|
|Peanut flour defatted||1 cup:60g||16.20|
|Wheat durum||1 cup:192g||12.64|
|Spaghetti whole-wheat, dry||8 oz:227g||11.65|
|Bacon meatless||1 cup:144g||10.89|
|Brewers yeast||1 oz:28g||10.61|
|Bakers yeast dry||1 oz:28g||10.28|
|Potatoes dehydrated granules||1 cup:200g||9.53|
|Rice bran crude||1/3 cu:28g||9.52|
|Millet raw||1 cup:200g||9344|
|Rice brown, long-grain, raw||1 cup:185g||9.42|
|Barley pearled, raw||1 cup:200g||.921|
|Sunflower seed kernels dry roasted||1 cup:128g||9.01|
|Brown rice medium-grain, raw||1 cup:190g||8.19|
|Spaghetti in tomato sauce w/cheese, canned||15oz can:432g||7.78|
|Wheat flour whole-grain||1 cup:120g||7.64|
|Mixed nuts with peanuts, oil roasted||1 cup:142g||7.19|
|Bulgar dry||1 cup:140g||7.16|
|Sesame seed kernels||1 cup:150g||7.02|
|Peaches dried||1 c halves:160g||7.00|
|Wheat germ crude||1cup:||6.81|
|Rice white, short-grain, cooked||1 cup:205g||6.79|
|Molasses cane, third extraction or blackstrap||1 cup:328g||6.56|
|Couscous dry||1 cup:184g||6.42|
|Dried mixed fruit||11 oz pkg:293g||5.65|
|Ginkgo nuts canned||1 cup:155g||5.62|
|Passion-fruit juice||1 cup:247g||5.53|
|Macaroni whole wheat, dry||1 cup:105g||5.39|
|Wild rice raw||Â½ cup:80g||5.39|
|Kindney beans sprouted, raw||1 cup:184g||5.37|
|Breakfast cereals e.g. corn flakes||1 serving:36.9g||50.2|
|Peas green, canned||1 lb:454g||4.99|
|Sweetcorn frozen, kernels||10 oz pkg:284g||4.90|
|Peas green, frozen||10 oz pkg:284g||4.85|
|Almonds dried||1 c whole kernel:142g||4.77|
|Sweetcorn canned||1 can:482g||4.53|
|Spaghetti in tomato sauce w/cheese, canned||1 cup:250g||4.50|
|Avocados raw||1 c puree:230g||4.42|
|Peanut butter||2 tbsp:32g||4.38|
|Tomato puree canned||1 cup:250g||4.29|
|Apricots dehydrated||1 cup:119g||4.26|
|Sausage meatless||1 patty:38g||4.25|
|Prunes dehydrated||1 cup:132g||3.95|
|Dates||1 cup chopped:178g||3.92|
Nicotinic acid, niacinamide, and inositol hexaniacinate (the three forms of Vitamin B3) have all proved very successful in various clinical applications. However, the forms of nicotinic acid and niacinamide consumed in access may prove to be toxic.
Conversely, inositol hexaniacinate has been supplemented in excess in scientific studies and proved tolerable. Inositol hexaniacinate has been shown to lower elevated LDL (bad cholesterol) and triglyceride (fat) levels in the blood, while concurrently raising the HDL (good cholesterol) levels. [3, 4] Inositol hexaniacinate has also been used for the prevention and treatment of peripheral vascular disease, especially intermittent claudication (or the atherosclerosis of the blood vessels in the legs that can cause pain with walking). 
Vitamin B3 may also be helpful in preventing the development of atherosclerosis, and may aid in the reduction of complications arising from those who suffer from specific heart conditions.  As well, vitamin B3 may prove to be as effective as prescription medications for treatment of atherosclerosis and problems associated with the heart.
Niacin, specifically the form of niacinamide, has also been shown to provide relief with complications resulting from diabetes. In a recent clinical study consisting of 343 individuals without diabetes and 125 with the disease, roughly 3000 milligrams per day was administered. Hemoglobin A1C (a particular measure of blood sugar over a period of time) actually decreased in the diabetic group over a 60-week follow-up period. [7, 8] Further research is needed on niacinamide, but intial studies indicate its potentiality in the treatment of arthritis. In addition, Vitamin B3 may reduce inflammation, increase joint mobility, and may also aid in cartilage repair. 
Eye health is another area of interest regarding the dietary supplementation of niacin. In a recent study that included participants from the U.S. and Australia, participants whose diets were supplemented with the highest amount of protein, Vitamin A, B1, B2, and B3 (niacin) were considerably less likely to develop cataracts.  Studies have also shown riboflavin and niacin alone, to be effective in the prevention of cataract formation. 
Ongoing applications of this B-vitamin compound include; vitamin replacement in burn victims, topical solutions for acne, and as an anti-cancer agent.
RDA for niacin was revised in 1998:
|19-30||16 mg/day||14 mg/day||18 mg/day||17 mg/day|
|50+||16 mg/day||14 mg/day|
Vitamin B3 Toxicities
Toxicity with Vitamin B3 mainly occurs with the form, Nicotinic acid. Signs of an overdose can produce vascular dilation (a flushing and itchiness of the skin), ulcers, liver damage, high blood sugar, and in extreme cases, paralysis of the respiratory tract.
Vitamin B3 Deficiencies
As mentioned before, the major deficiency linked with niacin depletion is pellagra. This disease is very uncommon in western societies due to the enrichment of foods and the availability of meat and milk products. Pellagra’s symptoms are usually referred to as the “four D’s:”:
- bilateral (on both sides of body) dermatitis
Other signs of Vitamin B3 deficiency include lesions and sores of the oral cavity.
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4. Alderman JD, et al. Effect of a Modified, Well-tolerated Niacin Regimen on Serum Total Cholesterol, High Density Lipoprotein Cholesterol and the Cholesterol to High Density Lipoprotein Ratio. Am J Cardiol. Oct1989;64(12):725-29.
5. O’Hara J, et al. The Therapeutic Efficacy of Inositol Nicotinate (Hexopal) in Intermittent Claudication: A Controlled Trial. Br J Clin Pract
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7. Gardner SF, Marx MA, White LM, et al. Combination of low-dose niacin and pravastatin improves the lipid profile in diabetic patients without compromising glycemic control. Ann Pharmacother. 1997;31(6):677-682.
8. Visalli N, Cavallo MG, Signore A, et al. A multi-centre randomized trial of two different doses of nicotinamide in patients with recent-onset type 1 diabetes (the IMDIAB VI). Diabetes Metab Res Rev. 1999;15(3):181-185.
9. Jonas WB, Rapoza CP, Blair WF. The effect of niacinamide on osteoarthritis: A pilot study. Inflamm Res. 1996;45:330-334.
10. Kuzniarz M, Mitchell P, Cumming RG, Flood VM. Use of vitamin supplements and cataract: the Blue Mountains Eye Study. Am J Ophthalmol. 2001;132(1):19-26.
11. Sperduto RD, et al. The Linxian Cataract Studies. Two Nutrition Intervention Trials. Arch Ophthalmol. Sep1993;111(9):1246-53.