Vitamin B3 (Niacin) Biochemistry



Vitamin B3 (Niacin) is a water-soluble vitamin which serves a key role as a precursor of the coenzymes NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate). Found in foods, niacin is also used pharmacologically as a treatment for lipid disorders, specifically for its ability to raise HDL ("good" cholesterol) and lower VLDL and LDL ("bad" cholesterols). The synthesis of niacin requires a number of factors, including tryptophan, Vitamin B2 (Riboflavin), and Vitamin B6 (Pyridoxine).

Key Points

  • Vitamin B3 (Niacin)
    • Constituent of NAD+ and NADP+ (used in redox reactions)
    • Synthesis requires tryptophan, Vitamin B2 and Vitamin B6
    • Used to treat dyslipidemia
      • Raises HDL levels
      • Lowers VLDL, triglyceride, LDL levels
        • Decreases hepatic production of VLDL, triglyceride release from adipose tissue, and decreases conversion VLDL to LDL

Find Niacin Biochemistry and other Vitamins among Pixorize's visual mnemonics for the USMLE Step 1 and NBME shelf exams.