Vitamin B3 has gained much attention in relation to it’s involvement in miscarriage.  Research by the Victor Chang Institute, published in the New England Journal of Medicine shows that deficiency of Vitamin B3 causes miscarriage.

So this begs the question, how does it prevent miscarriage?  What role does it really play in the body?  And should I be supplementing?  Here I present the facts about vitamin B3.  What it is, how it works, why it is involved in miscarriage and whether a supplement is right for you.

Vitamin B3 – The Facts

Other Names

You will see vitamin B3 referred to as Niacin, Nicotinic Acid and Nicotinamide.  These are all supplemental forms of vitamin B3.  They all function as vitamin B3 however they are each metabolised slightly differently meaning they exert slightly different effects on the body as well.  A Niacin supplement is converted to Nicotinamide by the body.


What role does it play in the body?

Energy and Metabolism

Alongside all the B Vitamins, Vitamin B3 is involved in healthy digestion and the conversion of food to energy.  It basically forms part of our metabolic ‘spark plug’, providing energy from food to get the body moving!

Nervous System

Vitamin B3 plays a role in the healthy functioning of the nervous system and stress response.

Hormone Production

B3 is required for the production of hormones including the sex hormones, thyroid hormone thyroxin and insulin.  Vitamin B3 further assists in stabilising blood sugar levels as a part of glucose tolerance factor (GTF).  Glucose tolerance factor (GTF) works in combination with insulin to help transport glucose to cells efficiently.  This helps to regulate blood sugar (and sugar cravings!) by transporting glucose to cells that require it to be used for energy.

Cardiovascular System

Vitamin B3 in the form of Niacin can help in cholesterol reduction.  It is the metabolic conversion of Niacin to Nicotinamide which exerts this effect.


As the new research shows, B3, alongside the already known vital prenatal nutrient B9 (folate), may play an important role during pregnancy.  It has been shown that lack of Vitamin B3 disrupts the development of an embryo and fetus, which can lead to severe birth defects and miscarriage.


How can I tell if I’m deficient?

Vitamin B3 deficiency is not common in developed countries being more associated with people experiencing chronic malnutrition or alcoholics, as alcohol can deplete all B Vitamins.

Signs and Symptoms

Mild Deficiency Severe Deficiency
Slow metabolism Pellagra
Poor tolerance to cold
Anxiety and Depression
Listlessness/Poor concentration

Symptoms of the severe vitamin B3 deficiency condition Pellagra, include digestive upset, diarrhoea, dermatitis and thickening of the skin and well as spotted ‘necklace’ like lesions around the neck, painful inflamed mouth and tongue as well as mental disturbance including dementia and delirium.  If left untreated, Pellagra can be fatal.


What are the best dietary sources?

Tuna, Turkey, Chicken, Fish, Veal, Beef, Pork, Salmon, Sardines, Scallops, Legumes, Peanuts, Sunflower seeds, Asparagus, Wheatgerm, Brown Rice, Bread, Milk, Yoghurt 


How much do I need?

Infants AI
0 – 6 months 2mg/day
7 – 12 months 4mg/day
Toddlers RDI
1 – 3 years 6mg/day
4 – 8 years 8mg/day
Children RDI
Boys 9 – 13 years 12mg/day
Boys 14 – 18 years 16mg/day
Girls 9 – 13 years 12mg/day
Girls 14 – 18 years 14mg/day
Adults RDI
Men 19 – 70 + years 16mg/day
Women 19 – 70 + years 14mg/day
Pregnancy RDI
14 + years 18mg/day
Lactation RDI
14 + years 17mg/day

There is no recommended Upper Limit (UL) for Vitamin B3 intake

Should I be taking a supplement?

Therapeutic doses of Niacin can be beneficial for those with high cholesterol, particularly high LDL cholesterol.  Vitamin B3 taken in combination with the other members of the B Complex family can be also be useful for those with low energy and/or under high stress as both these conditions utilise and deplete B vitamin stores.

Due to the recent, well publicised research into vitamin B3 and miscarriage, many have leapt to the conclusion that taking vitamin B3 will prevent miscarriage.   The aetiology of miscarriage is multifactorial.  Claims made that a single nutrient can prevent miscarriage would be a miraculous and of course much welcomed discovery but in reality, there are many causes for miscarriage.  Vitamin B3 deficiency is also uncommon in developed countries.  With most people getting the recommended amount of vitamin B3 from their diet as well as most prenatal multivitamins providing the recommended intake of vitamin B3, supplementation beyond recommended dosing is unlikely to be useful.  However, the discover of another factor involved in miscarriage that may be preventable, is very promising.

More research needs to be done to see if this discovery into vitamin B3 and miscarriage, which was done in animal models, translates to humans.  However ensuring a healthy intake of vitamin B3 preconception and during pregnancy as part of a healthy diet is a good start.


Is it possible to have too much?

Treatment doses of Niacin of 1000mg or more, will generally cause some degree of flushing/redness of the face.  This generally subsides after taking this dose for a few weeks.  Excess Niacin can also be associated with headaches and digestive upset.  Niacin can assist glucose tolerance however excess doses can actually upset blood sugar balance in some people, which is particularly important for diabetics.  Therapeutic doses of Niacin should always be taking under the advisement of your Health Care Practitioner.  Taking Vitamin B3 in the form of Nicotinamide is best for general supplementation and will not elicit these toxicity effects and can be combined with a small amount of Nicotinamide (Niacin) for an additional boost.