Nicotinic acid (niacin) is a vitamin that is produced in the body from its precursor - the essential amino acid - tryptophan. This production of nicotinic acid occurs in plants and in animals.
Nicotinic acid is absorbed in the small intestine in the form of nicotinate.
An important role of this vitamin is to lower cholesterol levels in the blood, and protection of various cardiovascular diseases. This feature was observed in the early 50's of the 20th century, when it was realized that nicotinic acid lowers cholesterol and triglycerides in the blood. Later, in 1975 that was confirmed.
Niacin has an important role in diabetes, and facilitates migraines. It is assumed, though not yet scientifically proven, that helps in arthritis (joint inflammation), and lowers blood pressure. It is essential for the synthesis of sex hormones (estrogen, progesterone, testosterone) and cortisone, thyroxin and insulin. This vitamin is needed for a healthy state of the nervous system and brain function.
Niacin is an ingredient of structure of two similar coenzymes:
- nicotinamide adenine dinucleotide (NAD) and
- nicotinamide adenine dinucleotide phosphate (NADP)
These compounds are co-factors of many oxidoreduction reactions. They are universal in its distribution and biological role.
Niacin is a conditional term for nicotinic acid, so it is not the synonym for nicotine contained in tobacco. The body nicotine is converted into nicotinic acid!
In liver cells about 60% of the total NADP is located in mitochondria and 40% in the cytoplasm.