Nicotinic acid

Vitamin B3 (Niacine) space filling model

Tryptophan metabolism

Nicotinic acid
Niacin.png
Structure of Nicotinic acid
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Properties
Chemical Formula	C6H5NO2
Molar Mass	123.11 g/mol
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Nicotinic acid (also known as niacin or vitamin B3) is an organic compound and a vitamer of vitamin B3, an essential human nutrient. It plays a vital role in metabolism and is involved in the production of nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), two crucial cofactors in redox reactions. This compound is produced by both plants and animals from the amino acid tryptophan.

Chemical Structure and Properties

Nicotinic acid has the chemical formula C₆H₅NO₂, and it belongs to the group of pyridinecarboxylic acids. It is characterized by its pyridine ring with a carboxyl group at the 3-position.

Pharmacology and Therapeutic Use

Nicotinic acid is also available as a prescription medication. When taken in amounts far in excess of the recommended dietary intake for its vitamin function, nicotinic acid can lower triglycerides and low-density lipoprotein cholesterol (LDL-C), and raise high-density lipoprotein cholesterol (HDL-C), often referred to as "good" cholesterol. These lipid changes have been used therapeutically to manage hyperlipidemia, a condition marked by high cholesterol levels.

There are two main forms of prescription nicotinic acid:

• Immediate-release nicotinic acid
• Sustained-release nicotinic acid

Dosage and Administration

For lipid management, initial prescription doses are typically 500 mg/day, which may be gradually increased over time until a therapeutic effect is achieved. The highest approved doses are:

• Immediate-release: up to 3,000 mg/day
• Sustained-release: up to 2,000 mg/day

Efficacy and Controversies

While nicotinic acid is effective at improving lipid levels, its overall impact on reducing cardiovascular disease risk has been debated. A 2010 review concluded that nicotinic acid was effective as a monotherapy for improving lipid profiles. However, a larger 2017 review, which incorporated twice as many trials, concluded that although nicotinic acid affected lipid levels, it did not reduce all-cause mortality, cardiovascular mortality, myocardial infarctions, or stroke. Furthermore, its use in individuals already prescribed a statin has not demonstrated additional benefits in terms of cardiovascular disease prevention.

Adverse Effects

Prescription nicotinic acid has been associated with several adverse effects. These include hepatotoxicity (liver damage), which may require monitoring of liver function during treatment. Other side effects include an increased risk of developing type 2 diabetes.

The use of nicotinic acid has also led to a decline in its prescription rates in the U.S., where prescriptions peaked at 9.4 million in 2009 and fell to 800,000 by 2020. Despite the proven lipid-altering effects, its long-term use has been reconsidered due to the associated risks.

Role in Metabolism

Nicotinic acid is a precursor to the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are essential for redox reactions involved in cellular energy production. These coenzymes also play a critical role in DNA repair and cellular repair mechanisms. NAD+ and NADP+ are involved in hundreds of enzymatic reactions throughout the body, which are crucial for proper cellular function.

Nicotinic Acid in Food Sources

Nicotinic acid is present in a variety of foods, including:

• Poultry
• Fish
• Whole grains
• Peanuts
• Legumes

The body can also synthesize nicotinic acid from the amino acid tryptophan, which is found in foods like turkey, chicken, and dairy products.

See Also

• Niacinamide
• Vitamin B3
• Hyperlipidemia
• Cardiovascular disease
• Hepatotoxicity
• Statins

External Links

• Niacin and its effects on lipids - NCBI
• Niacin - Medical News Today

Vitamins A Vitamin A B Biotin Vitamin B1 (see Thiamin) Vitamin B12 Vitamin B6 C Calcium Choline Chromium Copper Vitamin C D Vitamin D

E Energy Drinks Exercise and Athletic Performance Vitamin E F Fluoride Folate I Iodine Iron K Vitamin K

M Magnesium Multivitamin/mineral Supplements N Niacin P Pantothenic Acid Phosphorus Potassium Primary Mitochondrial Disorders R Riboflavin

S Selenium T Thiamin V Vitamin A Vitamin B1 (see Thiamin) Vitamin B12 Vitamin B6 Vitamin C Vitamin D Vitamin E Vitamin K Z Zinc

Nicotinic acid Resources
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