Vitamin B3 (niacin)

Why vitamin B3 (niacin) is good for you

Vitamin B3 (niacin) is required for more than 50 different processes in the body. Essentially, vitamin B3 (niacin) helps the body produce energy from the foods eaten. Vitamin B3 (niacin) makes enzymes that help the cells turn carbohydrates into energy. Vitamin B3 (niacin) helps control the level of blood glucose.

Vitamin B3 (niacin) also acts as an “on-the-spot” antioxidant within the cells, mopping up free radicals when it is being used to release the energy within the cells.

Vitamin B3 (niacin) works closely with vitamin B2 (riboflavin) and vitamin B6 (pyridoxine) to ensure good health by keeping the skin, nervous system and digestion working properly.

Important vitamin B3 (niacin) facts

• Most vitamin B3 (niacin) comes straight from the food we eat, but some is also made in the body from the amino acids (in the protein foods eaten). One of these amino acids is tryptophan – it is one of the nine essential amino acids the body needs. About half of the tryptophan in the food we eat is used to make some of the 500,000 proteins the body needs and the other half is used to make vitamin B3 (niacin)
• Vitamin B3 (niacin) helps the body use fats and sugars for energy
• Vitamin B3 (niacin) may help to lower LDL (bad) cholesterol and triglycerides, raising HDL (good) cholesterol and decreases risk of heart attack. Do NOT use vitamin B3 (niacin) for lowering cholesterol without consulting a medical professional
• Inositol hexa-Niacinate (IHN) is a form of nicotinic acid that also includes inositol (one of the B Vitamin co-factors). It works just as well as nicotinic acid and doesn’t cause flushing or other side effects
• Vitamin B3 (niacin) is heat-resistant – cooking foods will not destroy the niacin content. Vitamin B3 (niacin) does dissolve in water, so cook foods in as little water as possible, and try to use the liquid – don’t throw it away

Vitamin B3 (niacin) works best with

• Choline
• Folic acid
• Inositol
• Vitamin B1
• Vitamin B2
• Vitamin B3
• Vitamin B5
• Vitamin B6
• Vitamin B12
• Vitamin C
• Vitamin H (biotin)

Vitamin B3 (niacin) and health

• Intermittent claudation – intermittent claudation is a circulatory problem, which makes the legs ache and calf muscles cramp up upon walking. The reason is that the leg muscles are not getting enough oxygen because of poor blood circulation. Vitamin B3 (niacin) makes the blood vessels widen, which brings more blood to the legs and helps with normalising blood circulation
• Dizziness (vertigo) and ringing in the ears (tinnitus) – niacin sometimes helps relieve tinnitus and vertigo, although doctors are not quite sure why
• PMS headaches – B vitamins in general help some women who have PMS. Vitamin B3 (niacin) seems to help PMS headaches

Talk to a medical professional about vitamin B3 (niacin) supplements before taking them.

Groups at risk of vitamin B3 (niacin) deficiency

• Alcoholics – absorb less of some of the B vitamins and may not eat properly
• Strict vegetarians or vegans – if good quality protein from animal sources, such as milk, eggs, fish and meat are not eaten niacin levels may be low, which is why people who are on vegetarian diet may become deficient

Talk to a medical professional about vitamin B3 (niacin) supplements before taking them.

Symptoms of vitamin B3 (niacin) deficiency

Because not much niacin is required and because it can be made from the tryptophan in protein, real niacin deficiency is rare in western and developed countries.

Early deficiency symptoms are:

• sores and cracks on the lips, especially around the corners
• Scaly skin
• red eyes
• anaemia

The disease pellagra is caused by a deficiency of niacin and it has three main symptoms:

• dermatitis – dry, cracked, scaling skin aggravated by sunlight;
• dementia – lack of niacin affects the brain causing confusion and memory loss;
• diarrhoea – this occurs when the intestines are affected

Vitamin B3 (niacin) in food

Vitamin B3 (niacin) recommended daily intake (RDI)

The tolerable upper limits should only be taken for short periods and only under medical supervision.

Overdosage, toxicity and cautions for vitamin B3 (niacin)

Vitamin B3 (niacin) has limited toxicity in normal, otherwise healthy adults. Really large doses of vitamin B3 (niacin) can cause flushing, burning sensation, diarrhoea, increased heart and breathing rates, itching skin, high blood pressure and liver abnormalities, which are all reversible when intake is stopped.

Precautions

• Vitamin B3 (niacin) supplements should NOT be taken by people on medication for high blood pressure, without discussing it with a medical professional, as niacin could make blood pressure drop really low.
• Vitamin B3 (niacin) supplements could make blood glucose levels rise too high in diabetics
• Vitamin B3 (niacin) supplements could raise uric acid levels and cause an attack of gout
• Vitamin B3 (niacin) supplements could make ulcers, high blood pressure or liver problems worse

Discuss vitamin B3 (niacin) supplementation with a medical professional

References

• Brown BG, Zhao XQ, Chalt A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med. 2001;345(22):1583-1592
• Food and Nutrition Board, Institute of Medicine. Pantothenic acid. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B-6, Vitamin B-12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press; 1998:357-373
• Jonas WB, Rapoza CP, Blair WF. The effect of niacinamide on osteoarthritis: A pilot study. Inflammation Research 1996; Vol 5(7); 330-334
• Mills E, et al. The safety of over-the-counter niacin. A randomized placebo-controlled trial. BMC Clinical Pharmacology 2003, 3:4
• Office of Dietary Supplements USA – has the official USA RDI for all vitamins (these are also adopted by Australia), accessed 9 August 2005
• Osiecki, Henry, The Nutrient Bible 2002, BioConcepts Publishing

Last reviewed and updated: 9 May 2024