What is a key function of niacin in the body?

Niacin, also known as vitamin B3, plays a vital role in energy metabolism within the body. Specifically, it is indispensable for the production of coenzymes such as NAD (Nicotinamide adenine dinucleotide) and NADP (Nicotinamide adenine dinucleotide phosphate), which are critical for various biochemical reactions involved in the metabolism of carbohydrates, fats, and proteins. These coenzymes facilitate the conversion of macronutrients into energy, supporting overall cellular function and energy levels.

While niacin has other important roles, such as contributing to the health of skin and nerves, its primary and essential function is related to energy production. Other options presented do not accurately reflect the core roles of niacin; for instance, the regulation of body temperature and the promotion of bone health are not directly influenced by niacin, and collagen production primarily involves other nutrients like vitamin C and specific amino acids. Thus, the key function of niacin clearly aligns with its role in energy metabolism.