One of the best sources of niacin is fish, particularly mackerel and swordfish. Niacin can also be found in chicken, veal, pork, salmon, milk, eggs, fortified cereals, avocados, and some nuts. Niacin deficiency causes pellagra, a chronic disease characterized by skin eruptions, digestive and nervous disturbances and mental deterioration. The condition can usually be reversed by taking niacin supplements. Anemia may also occur as a result of low niacin levels, although this is usually due to an accompanying deficiency in folic acid.
Niacin toxicity can lead to a variety of conditions.
Larger doses may cause diarrhea, nausea, ulcers, gout, diabetes and in rare cases, liver damage. DSHP therapeutic position statement on the safe use of niacin in the management of dyslipidemias. American Society of Health System Pharmacists. Effect of niacin on atherosclerotic cardiovascular disease. Recommended Dietary Allowances, 10th ed.