Last updated by Dr Sarah Brewer on
Vitamin B3 benefits relate to energy production and improved skin health. Vitamin B3 is a water-soluble vitamin that is also known as niacin. It exists in two main forms, as nicotinic acid and nicotinamide which have slightly different effects in the body.
Unlike most vitamins, you can make small amounts of vitamin B3 from the essential amino acid, tryptophan. You need around 60 mg tryptophan to produce 1 mg niacin so the conversion is not that efficient. The amount of vitamin B3 obtained from foods and supplements is sometimes described as niacin equivalents which are calculated from the amount of nicotinamide and nicotinic acid they provide plus one-sixtieth of their tryptophan content.
Vitamin B3 benefits
Like other B vitamins, vitamin B3 is involved in the metabolism of proteins, fats and carbohydrate to produce energy in cells.
Vitamin B3 is used to produce two factors, NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate) which activate over 200 enzymes involved in energy production, the synthesis of fatty acids and steroid hormones.
Vitamin B3 is also needed to make a special sugar, ribose, which forms part of the backbone of your genetic code (DNA and RNA).
Vitamin B3 regulates the production of triglyceride fats in the liver, and increases your production of ‘good’ HDL-cholesterol.
Some evidence suggests that vitamin B3 also combines with the mineral, chromium, and three amino acids (glycine, cysteine, glutamic acid) to form a complex known as Glucose Tolerance Factor (GTF) although its structure has not been established. Glucose Tolerance Factor appears to mimic and boost the effects of insulin hormone to regulate the uptake of glucose into body cells. Lack of vitamin B3 has been associated with impaired glucose tolerance which may lead to diabetes.
Within the EU, the European Food Safety Authority has authorised health claims that vitamin B3 (niacin) contributes to:
- Normal energy-yielding metabolism
- Normal psychological function
- Normal functioning of the nervous system
- The maintenance of normal mucous membranes
- The maintenance of normal skin
- The reduction of tiredness and fatigue.
Food Sources of vitamin B3
Vitamin B3 is widely found in the diet, with animal-based food supplying the highest amounts. Dietary sources of vitamin B3 include the following niacin equivalents per 100g food:
- Oily fish, especially tuna (22.1mg)
- Liver (16.7mg)
- Chicken or turkey breast (14.8mg)
- Nuts, especially peanuts (13.8mg)
- Meats, especially lean pork (10.9mg)
- Beef (9mg)
- Seeds, especially sunflower seeds (8.3mg)
- Portobello mushrooms (6.3mg)
- Fresh green peas (2.1mg)
- Avocado (1.7mg)
Niacin is also found in fortified cereals and yeast extract, while eggs and cheese are among the richest dietary sources of the amino acid, tryptophan.
Vitamin B3 deficiency
Lack of vitamin B3 produces a deficiency disease known as pellagra, whose name derives from the Italian pelle agra which means rough or raw skin.
Pellagra is seen in parts of Africa where the diet consists mainly of maize whose niacin is in a non-usable form called niacytin. Soaking maize overnight in a calcium hydroxide solution releases usable niacin, however, and the disease is less prevalent in central America where this method is used when making tortillas.
Drinking alcohol depletes body levels of niacin and people who drink alcohol regularly need more B vitamins than those who drink little alcohol.
Symptoms that may be due to vitamin B3 deficiency include:
- loss of appetite
- impaired glucose tolerance
- impaired cholesterol balance
- fatigue, weakness.
Symptoms that may be due to a major lack of vitamin B3 are:
- dry, scaly skin in areas exposed to light
- sore, fissured tongue
- inflamed gut and diarrhoea
- depression and irritability
- memory loss.
Vitamin B3 and cholesterol
Vitamin B3 in the form of nicotinic acid has a direct action on the liver to lower a raised level of ‘bad’ LDL-cholesterol and high triglycerides. Niacin has the additional benefit of blocking the breakdown of ‘good’ HDL-cholesterol and can increase circulating levels by as much as 30%. Niacin is prescribed medically to improve cholesterol balance but whether or not this protects against coronary heart disease remains unclear. here ple
Vitamin B3 and skin cancer
Vitamin B3 helps to protect skin from the harmful effects of ultraviolet light. Vitamin B3 deficiency results in a severe form of eczema-like dermatitis in sun-exposed areas of the skin such as the face, hands and neck.
Treatment with nicotinamide (500mg twice a day) has been shown to reduce the rate of formation of skin cancers and of premalignant skin lesions called actinic keratoses, especially in people at high risk. An Australian study involving people with a previous history of at least two skin cancers found that those who took 500mg nicotinamide twice a day, for 12 months were 20% less likely to develop a new basal cell carcinoma and 30% less likely to develop a new squamous cell carcinoma over the course of the year than those taking placebo.
Vitamin B3 dose
People who are physically active need more niacin than sedentary people. Requirements also increase during pregnancy and lactation.
The average Western diet supplies 34mg niacin per day.
Vitamin B3 is included in multivitamins and minerals, and in high dose Vitamin B Complex supplements.
High dose vitamin B3 in the form of nicotinic acid can cause side effects such as flushing, itching, low blood pressure or headache which limits its use. People who blush easily are more sensitive to this effect.
A drug that combines nicotinic acid with an agent to reduce flushing (laropiprant) is available on prescription. Flushing can also be reduced by taking low dose aspirin (75–300 mg) half an hour before the dose of niacin.
Excessive long-term use of vitamin B3 can cause thickening and darkening of patches of skin (acanthosis nigricans), palpitations, gout and cause liver enzymes to rise. This occurs in 20% ofpeople taking niacin in doses above 500mg per day and is most common in doses above 3g per day.
Liver toxicity can also occur, with high doses of sustained release niacin. Symptoms include jaundice, itching, nausea, vomiting and fatigue. Do not exceeed manufacturer’s recommended dose except under medical supervision.
The European Food Safety Authority have therefore determined a tolerable upper intake level for nicotinic acid of 10 mg/day and for nicotinamide of 900mg per day.
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