What is the deficiency disease associated with a lack of niacin (Vitamin B3)?

Pellagra is the deficiency disease that occurs due to a lack of niacin (Vitamin B3). This condition is characterized by a classic triad of symptoms: dermatitis, diarrhea, and dementia. These symptoms arise because niacin plays a critical role in the metabolism of carbohydrates, fats, and proteins, as well as in the production of energy and the synthesis of various hormones. When the body does not receive enough niacin, these metabolic processes become impaired, leading to the distinct symptoms associated with pellagra.

The other conditions listed—scurvy, beriberi, and rickets—are caused by deficiencies of different vitamins. Scurvy is linked to a lack of vitamin C, beriberi results from a deficiency in thiamine (Vitamin B1), and rickets is caused by insufficient vitamin D or calcium. Each of these conditions has a specific set of symptoms and causes, distinct from the symptoms associated with niacin deficiency.