The deficiency of which one of the following causes a disease called Pellagra ?

Pellagra is a systemic disease caused by a deficiency of niacin, also known as vitamin B3 [t2][t4]. Niacin exists in two primary forms: nicotinic acid and nicotinamide [t3]. Historically, the condition was prevalent in populations relying heavily on corn-based diets, as corn is low in the amino acid tryptophan, which the body can convert into niacin [t7]. In 1937, researchers demonstrated that pure nicotinic acid could reverse the symptoms of pellagra [t2]. The disease is clinically characterized by the '3 Ds': dermatitis (skin inflammation), diarrhea, and dementia [t1][t8]. In contrast, deficiency of ascorbic acid (Vitamin C) causes scurvy, and folic acid (Vitamin B9) deficiency leads to megaloblastic anemia and neural tube defects [t6]. Therefore, nicotinic acid is the specific nutrient whose deficiency results in pellagra.

Sources

1. [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC12400341/
2. [2] https://www.ncbi.nlm.nih.gov/books/NBK557728/
3. [3] https://en.wikipedia.org/wiki/Pellagra