Just like other B-type vitamins, vitamin B3, also called niacin, is necessary for proper metabolism. Two important coenzymes, NAD and NADP are created from vitamin B3, both essential to energy production. NAD is needed for the function of over 400 enzymes; NADP assists the production of cholesterol and fatty acids, and also supports antioxidant function of cells.(1) 

Vitamin B3 deficiency can lead to pellagra, a disease with such symptoms as dermatitis, diarrhoea and dementia; in serious cases, it can even be fatal. Fortunately, pellagra is very rare nowadays, since niacin can be found in most food, and varied diets certainly include the right dosage. Should that not be the case, proper protein intake can prompt the body to produce vitamin B3. Vitamin B3 deficiency is typically present in developing countries where the main food source is corn, and people generally don’t have access to other types of food.(2) 

Types of vitamin B3 

Vitamin B3 can be found in organic food in the forms of niacinamide, niacin and, in rare cases, niacinamide-riboside. Meat, eggs, various dairy products, whole wheat and potatoes are among its sources. Vitamin B3 (in the form of niacin or niacinamide) can also be found in dietary supplements, multivitamins, B-complex products, or sold separately as vitamin B3.  

Vitamin B3 has an artificial version as well, inositol hexanicotinate, which was originally marketed as an anticholesterol, but proved to be quite ineffective: only 70% of it gets absorbed, and it takes a while to break down. As a result, it’s very slow to increase niacin levels in the blood, unlike organic forms, the 100% of which gets absorbed and their concentration rises then falls in the blood quickly. Since the long-term effects of a consistently high niacin level are unknown, it’s best to avoid this form. (3) 

We can supply proper levels of vitamin B3 effortlessly through a varied diet, but its continuous, large dose supplementation may possibly have a negative long-term effect. For this reason, vitamin B3 supplementation is only recommended for people whose diet does not include animal produce or other vitamin B3 rich sources. (4) 

Therapeutic effects of large dose vitamin B3 

It must be noted that these effects are only applicable to the medicinal use of massive doses of vitamin B3 applied to special complications. While the recommended daily intake of vitamin B3 is around 15-20 mg, therapeutic doses can reach and even exceed a daily intake of 1000 mg. Although the body can quickly clear out vitamin B3, continuous high-dose supplementation can have known and supposedly negative effects. In some cases, massive dose niacin supplementation resulted in organ failure in young people who tried to use it to trick drug tests. (5) 

A common side effect of large dose niacin supplementation is niacin-flush, which turns the skin red, then causes an itchy, burning sensation. This is the reason many people stop niacin supplementation; the good news is that niacinamide does not cause this side effect. 

Niacin supplementation have been studied often in connection with cardiovascular diseases, but to mixed results: while it successfully decreased the risk of heart attacks and stroke, it did not help prevent fatalities caused by the cardiovascular system. (9) The reason might be that large doses of niacin have an expressly negative effect on insulin sensitivity and blood sugar levels: it increases fasting blood sugar and insulin levels and decreases insulin sensivity. (10) Caution is advised, especially for those who have blood sugar issues.  

Niacin used as an external cream containing 4-5% niacinamide improves the skin’s quality and elasticity, and in a study it decreased acne symptoms to the same level as the acne medicine also used in the study. (11) (12) 

Fun facts 

Following its discovery, niacin used to be called nicotinic acid, but when it was first  added to food, sensationalist newspapers connected it to smoking. Official organisations  decided to rename it to niacin and niacinamide to prevent this inconvenient  issue  and so that people don’t  get confused about the health impacts of the vitamin.  

Summary 

Vitamin B3 has an important role in metabolism. Vitamin B3 deficiency is rare, as the vitamin can be found in most organic food and the necessary amount of 16-20 mg/day can be easily covered through food. High dose supplementation has been studied frequently, but one must be careful, since in the long run, it can have a negative effect on blood sugar levels and insulin sensitivity.  

[The cover photo of the note shows corn. its 100 grams contain 1.8 mg of vitamin B3, which provides one-tenth of the daily requirement.]