whw-class

B3 (Niacin)

Niacin is water soluble and is more stable than thiamin or riboflavin. There are three synthetic forms of niacin: nicinamide, nicotinic acid and nicotinamide. As a coenzyme, it assists enzymes in the breakdown and utilization of proteins, fats and carbohydrates.

Niacin has been used to improve circulation and to reduce cholesterol. Tryptophan can be converted into niacin by the body. Excessive consumption of sugar and starches will deplete the body’s supply of niacin.

Niacin, in doses of 100mg or more can cause an unpleasant flush. Taking niacinamide does not cause the flush. In doses of 2g per day or more, it can cause liver damage. High doses may also precipitate a gout attack, or make a case of gout worse, by competing with the excretion of uric acid. Niacin is involved with the release of stomach acid and should therefore be taken on a full stomach.

Niacin deficiency, in the early stages, leads to muscular weakness, general fatigue, loss of appetite, indigestion, and various skin eruptions. It can also cause bad breath, small ulcers, canker sores, insomnia, irritability, nausea, vomiting recurring headaches, tender gums, and depression.

Severe deficiency leads to pellagra, which is characterized by the three Ds, dermatitis, dementia and diarrhea. Primary deficiency usually occurs in areas where maize (Indian corn) is a major part of the diet. Bound niacin, found in maize, is not assimilated in the intestinal tract (unless treated with alkali–as in making of tortillas). Corn protein is also deficient in tryptophan. Amino acid imbalance may also play a part. Pellagra is common in India, among those who eat a lot of millet (which has a high leucine content). Also can be seen in diarrheal disease, cirrhosis of the liver and alcoholism.

Pellagra is characterized by cutaneous, mucous membrane, CNS and GI symptoms. The complete syndrome of advanced deficiency includes scarlet stomatitis and glossitis, diarrhea, dematities and mental aberrations. Symptoms may occur alone or in combination.

Cutaneous lesions are usually bilaterally symmetric. There are four types: (1) acute–erythema followed by vesiculation, bullae, crusting and desquamation; secondary infection is common, notably following exposure to sunlight. (2) intertrigo, also an acute lesion, characterized by redness, maceration, abrasion and secondary infection in the intertriginous areas; (3) chronic hypertrophy, in which the skin is thickened, inelastic, fissured and deeply pigmented over pressure points; secondary infection often develops and the lesion shows a sharply defined pearly border or regenerating epithelium when healing begins and (4) chronic atrophic lesions, with dry, scaly  and inelastic skin too large for the part it covers. Sunlight causes Casal’s necklace and butterfly-shaped lesions on the face.

Changes in the mucous membranes usually involve the mouth, but may affect the vagina and urethra. Scarlet glossitis and stomatitis are common. It starts on the tip and margins of the tongue. As the lesion progresses, the entire tongue and oral mucous membranes become a bright scarlet color, followed by sore mouth, increased salivation and edema of the tongue. Ulcerations may appear, especially under the tongue and the mucosa of the lower lip.

GI symptoms include burning of the mouth, pharynx and esophagus, and abdominal discomfort and distention. Later, nausea, vomiting, and diarrhea. In serious cases diarrhea may be bloody due to GI hyperemia and ulceration.

CNS symptoms can include memory impairment, disorientation, confusion, and confabulation (excitement, depression, mania and delirium). Some patients may become paranoid. CNS symptoms may manifest as “encephalopathic syndrome” which is characterized by clouding of consciousness, cogwheel rigidity of the extremities and uncontrollable sucking and grasping reflexes.

Z Vitamin-forsch 15:245-50     Niacin supplementation for acne rosacea is beneficial. Daily IV injections of nicotinaminde 20 cg rapidly improves skin lesions. The day after the first injection the lesions are already less intense. After some days this improvement is very marked. They subsequently remain stationary and never completely disappear, despite the continuation of treatment.

Am J Epidemiol 132 (1):67-76, 1990   Niacin and asthma. Increased dietary niacin was associated with a reduced rate of wheezing. Individuals in the 16th percentile of niacin intake had 25% more wheezing than those in the 84th percentile. Also, there seems to be an association between low serum levels and wheezing.

Agents Actions 4(3): 196, 1974    Guinea pigs given nicotinamide, then exposed to histamine aerosols, appearance of the first symptoms of dyspnea was delayed and the number of animals developing anaphylactic shock diminished significantly. Nicotinamide, which itself produces a slight bronchial constriction in isolated guinea pig lungs, not only protects against histamine constriction, but relaxes histamine induced bronchial constriction after 3-4 minutes.