Human Nutrition 3(3+0)

Lesson 26 : Nicotinic Acid (Niacin)

Introduction

Common names: Niacin, Nicotinic Acid, Nicotinamide / Niacinamide

• Niacin exists in two forms, nicotinic acid and nicotinamide. Both forms are readily absorbed from the stomach and the small intestine.
• Niacin is stored in small amounts in the liver and transported to tissues, where it is converted to coenzyme forms. Any excess is excreted in urine.
• Niacin is one of the most stable of the B vitamins. It is resistant to heat, light, acid and alkali environments.
• The human body is capable of converting the amino acid tryptophan to niacin when needed. However, when both tryptophan and niacin are deficient, tryptophan is used for protein synthesis.