Vitamin B3 (niacin)

Part of NAD/NADP for energy production, repair and cell metabolism.

Swiss reference value

Switzerland age 18–65: 1.6 mg niacin equivalents per MJ.

Good food sources

Meat, fish, peanuts, whole grains and mushrooms; also made from tryptophan.

When intake or status is low

Pellagra with dermatitis, diarrhoea and neurological/mental changes; severe deficiency can be fatal.

Long-term health connections

Now rare except with severe malnutrition, malabsorption or specific disease.

Skin, hair and nails

Symmetric sun-exposed dermatitis can be a sign but requires medical assessment.

Who is more at risk

Severe malnutrition, alcohol dependence, malabsorption and Hartnup disease.

How to assess it

Clinical picture and diet; laboratory testing is not always routinely available.

Supplements: when to consider

Not a general longevity supplement. Pharmacological nicotinic acid requires medical supervision because of adverse effects.

Too much and safety

High doses can cause flushing, itching, raised glucose and liver injury.

International reference systems