Vitamin B3

Vitamin B3, also known as niacin or nicotinic acid, is a water-soluble vitamin, used by the human body as nicotinamide (also called ‘niacinamide’) to form the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). None of the forms are related to the nicotine found in tobacco, although their names are similar (1).

Since nicotinic acid can also be synthesized in humans from the amino acid tryptophan, it does not qualify as a vitamin provided that an adequate dietary supply of tryptophan is available.

Health functions

Most of the energy that living organisms use is derived from oxidation-reduction (redox) reactions, involving the transfer of electrons. About 200 enzymes require the vitamin B3 (niacin) coenzymes, NAD and NADP, mainly to accept or donate electrons for ‘redox reactions’.

Disease risk reduction

In vitro (cell culture) studies provide evidence that vitamin B3 (niacin) coenzyme NAD content influences the cellular response to DNA damage, an important risk factor in cancer development (4, 5, 6).

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Things to know about Vitamin B3

  • Other applications

    The Coronary Drug Project (CDP) followed over 8,000 men with a history of heart attack (‘myocardial infarction’) for six years (13).

  • Intake recommendations

    The optimum intake of vitamin B3 (niacin) for health promotion and chronic disease prevention is not yet known.

  • Supply situation

    Intake data from a number of European countries indicate that average intakes of vitamin B3 (niacin) for adults (20–40 mg/day) are above those recommended (23).

  • Deficiency

    The most common symptoms of niacin deficiency involve the skin, digestive system, and nervous system (2).

  • Sources

    Good sources of vitamin B3 (niacin) include yeast, meat, poultry, red fish (e.g., tuna, salmon), cereals, legumes, and seeds. Milk, green leafy vegetables, coffee, and tea also provide some niacin (3).

  • Safety

    While vitamin B3 (niacin) from foods is not known to cause adverse effects, side effects have been reported with preparations of niacin for disease treatment (22).

  • References

    Consult the full list of scientific references.