Which B vitamin serves as a catalyst in over 400 reactions in the body and can cause pellagra when deficient?

Niacin, or vitamin B3, plays a crucial role in the body as it is involved in numerous biochemical reactions, particularly those related to energy production and metabolism. It functions primarily by serving as a precursor to coenzymes, namely NAD (Nicotinamide Adenine Dinucleotide) and NADP (Nicotinamide Adenine Dinucleotide Phosphate), which are essential for more than 400 enzymatic reactions. These coenzymes are vital for converting carbohydrates, fats, and proteins into energy, among other metabolic processes.

A deficiency in niacin can lead to a condition known as pellagra, characterized by symptoms such as dermatitis, diarrhea, and dementia. This condition arises because the body cannot effectively utilize energy from nutrients due to insufficient niacin levels, disrupting many cellular processes.

Biotin is primarily associated with carbohydrate, fat, and protein metabolism, while pyridoxine is involved in amino acid metabolism and neurotransmitter synthesis. Folate is primarily important for DNA synthesis and repair, especially during periods of rapid growth. While all these vitamins are essential in their own right, none link specifically to the widespread enzymatic functions or the specific deficiency symptoms associated with niacin. Therefore, understanding niacin's extensive role and its deficiency effects further emphasizes