Niacin (Vitamin B3) deficiency
Niacin or vitamin B3 is important for the proper functioning of the nervous system and the metabolism of carbohydrates, fats, and proteins.
Deficiency in niacin presents with weakness, fatigue, loss of appetite, and skin problems such as rashes or hyperpigmentation. Severe niacin deficiency can lead to a condition called pellagra, which is characterized by diarrhea, dermatitis, dementia, and death.
Niacin deficiency is commonly caused by inadequate intake of niacin or tryptophan, an amino acid that the body can convert into niacin. The treatment is usually increasing the intake of niacin through diet or supplements.