It is rare for anyone in the developed world to have a niacin deficiency. In the United States, alcoholism is the main cause of naicin deficiency. Intestinal problems, including chronic diarrhea, inflammatory bowel disease, and irritable bowel disease can all trigger niacin deficiency. Because part of your body’s niacin supply comes from conversion of the amino acid tryptophan, deficiency of tryptophan can also increase risk of niacin deficiency. (Foods rich in tryptophan include crimini mushrooms, soybeans, tofu, sunflower seeds, spinach, and asparagus.) The conversion of tryptophan to niacin also requires the presence of thiamine and vitamin B6, and when thiamine or B6 are deficient, niacin can also become deficient. Niacin deficiency also appears to be related to vitamin B12 status, since even mild deficiencies in vitamin B12 can increase loss of niacin in the urine. Physical trauma, all types of stress, long-term fever, and excessive consumption of alcohol have also been associated with increased risk of niacin deficiency. Symptoms of mild deficiency include indigestion, fatigue, canker sores, vomiting, and depression. Severe deficiency can cause a condition known as pellagra. Pellagra is characterized by cracked, scaly skin, dementia, and diarrhea. It is generally treated with a nutritionally balanced diet and niacin supplements. Niacin deficiency also causes burning in the mouth and a swollen, bright red tongue.