Vitamin B3 (niacin) deficiency can cause skin inflammation, canker sores and eruptions (rashes)

Vitamin B₃ is one of the eight water-soluble B vitamins. It is also known as Niacin. Niacin is derived from two compounds - nicotinic acid and niacin amide.
Its mild deficiency slows down the metabolism.
This results in low tolerance to cold. Severe deficiency of Niacin causes the disease pellagra.
Niacin is important for ridding the body of harmful and toxic compounds.
Niacin has effect on the hormone glands of the body and helps in their healthy condition for the normal healthy life.
In human body the amino acid tryptophan can be converted into niacin.
Niacin improves circulation and cell respiration. Apart from being a memory enhancer it helps in treatment of mental illness and schizophernia.
Deficiency
Corn is low in niacin and in places where corn is the staple food the deficiency of niacin is found.
Shortage of niacin shows symptoms such as loss of appetite, indigestion, diarrhea, depression, dizziness, headaches, insomnia, low blood sugar, fatigue, muscular weakness, limb pains, skin eruptions, canker sores, and inflammation.
 Severe deficiency may cause pellagra, the well known niacin deficiency disease, and is characterized by bilateral dermatitis, diarrhea, and forgetfulness.
Toxicity
Heavy long term dosages have been found to cause liver damage though higher dosages have been found to treat a number of ailments.
Niacin has been found to lower bad cholesterol and increase good cholesterol. Niacin has been found to be effective in prevention and treatment of atherosclerosis and heart diseases.
Physician must be consulted before using high doses.
 The best dietary sources of niacin are found in beetroot, yeast, liver, meat, chicken, fish, unrefined cereals except corn, fruits and vegetables.
For more information visit http://www.thedynamicnature.com/vitamins/vitamin%20B3.html.