Vitamin B3

Authored by Robert Chen • 
August 17, 2016
 • 2 min read

Vitamin B3, also known as niacin, is a vitamin that is a useful precursor for nicatinamide adenide dinucleotide (NAD), which is an important energy source in many metabolic processes.

Pharmacology of Vitamin B3

Vitamin B3 bears the structure of a pyridine ring with a carboxyl group at the 3' carbon. Vitamin B3 is typically synthesized from the amino acid tryptophan.


Vitamin B3 chemical structure.

Vitamin B3 and Mental Performance

While many clinical trials have successfully shown that vitamin B3 can help to improve memory and attention in those with cognitive decline, there is limited evidence that shows vitamin B3 has enhancement effects in the normal human population.

With respect to cognitive decline, a small number of studies have been conducted that suggested some slowing of cognitive decline if chronic vitamin B3 supplementation is done. One of the largest studies that showed this relationship was one conducted on 6158 Chicago residents over a period of 10 years from 1993 to 2002. In this cohort, the participants recorded dietary intake over the years and also conducted cognitive testing every 3 years. After the observation period it was found that intake of vitamin B3 was associated with a slower annual rate of cognitive decline, by 0.019 standardised units (SU) per natural log increase in intake (mg) (p = 0.05). What's more fascinating was that the relationship was even stronger for people with below average cognition (less than 12 years worth of formal education, and exhibiting below average baseline cognitive scores).1

Sources of Vitamin B3

It is recommended that receive up to 14 mg/day (females) to 16 mg/day (males) of vitamin B3.

Vitamin B3 can be found in various foods. Foods that have considerable vitamin B3 content include meats, red fish such as tuna and salmon, legumes and seeds.2

In general, meats have the highest amount of vitamin B3. For example, a 75g serving of tuna contains 12 to 18 mg vitamin B3. A 75 g serving of red meat such as pork or beef has roughly 6 to 14 mg of vitamin B3. In grains, a slice of bread has about 2 mg of vitamin B3 while a cup of oatmeal contains roughly 4-6 mg of vitamin B3.

Side effects of Vitamin B3

It is important to note that there are various side effects ranging from minor to severe in intensity. Vitamin B3 should not be consumed in quantities of more than 3 g per day. Excess vitamin B3 in the human body can lead to flushing of the skin.3

Vitamin B3 deficiency can lead to symptoms in the nervous system, digestive system and skin. The most notable symptoms of vitamin B3 deficiency are diarrhea, dermatitis and dementia. Severe vitamin B3 deficiency is also known as pellagra, and if left untreated it can lead to death. Pellagra is often treated by supplementing the patient's diet with up to 300 mg/day of vitamin B3 (20 times the recommended daily value).4

Editor's Note

Vitamin B3 Vitamin B3 is classified as a Generally Regarded as Safe compound by the FDA. Vitamin B3 is essential to health of the nervous system and digestive system, and there are no major side effects when consumed within safe quantities. While there is limited research showing that vitamin B3 can significantly enhance cognitive performance, it is still important to consume an adequate amount of vitamin B3 each day. While typically you can get enough vitamin B3 through food, you may wish to supplement your diet with up to 16 mg /day (males) or 14 mg/day (females).

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