What deficiency disease is caused by a lack of vitamin B3 (niacin) in the diet?

Pellagra is the deficiency disease specifically associated with a lack of vitamin B3, also known as niacin. This condition is characterized by the classic symptoms of dermatitis, diarrhea, and dementia, often referred to as the "three D's." When an individual does not consume sufficient niacin through food sources or through the body's conversion of the amino acid tryptophan, they can develop pellagra.

The significance of niacin in the body includes its role in various metabolic processes, particularly in the conversion of carbohydrates, fats, and proteins into energy. It is also crucial for the synthesis of certain hormones and DNA repair. A deficiency in this nutrient disrupts these processes, leading to the symptoms associated with pellagra.

In contrast, the other conditions listed result from different nutrient deficiencies. Scurvy, for example, is caused by a lack of vitamin C, while beri-beri is linked to a deficiency of thiamine (vitamin B1), and rickets arises from insufficient vitamin D, calcium, or phosphate. Understanding these distinctions is crucial for recognizing deficiency diseases and their corresponding nutritional requirements.