Vitamin B3 deficiency (Pellagra)
Linked to Vitamin B3 (Niacin)
Niacin deficiency causes the classic "three Ds": dermatitis, diarrhoea and dementia.
Where it shows on the body
Rotate the figure and click a red marker to see the affected area. Internal organs open a 3D organ model.
Causes
- Maize-based diets without treatment
- Malnutrition
- Alcohol dependence
- Malabsorption
Symptoms
- Rough, darkened skin in sun-exposed areas
- Diarrhoea
- Confusion and memory loss
- Sore mouth
What happens if untreated
- Progressive dementia
- Can be fatal if untreated
Who is most at risk
- People with very restricted diets
- Heavy drinkers
Prevention & sources
- Meat, fish, peanuts and wholegrains
- Niacin supplements where needed
Correcting it: foods, amounts & timing
Foods that help & safe amounts
- Meat, fish, peanuts, and wholegrains
- Niacin (or nicotinamide) supplements as prescribed
Skin and digestive symptoms often improve within a week or two of treatment.
Sources & references
Symptoms overlap — testing matters
Most deficiency symptoms (fatigue, poor concentration, skin and hair changes) are shared across several nutrients and many unrelated conditions. A symptom on this page is a reason to investigate, not a diagnosis.
A GP can confirm or rule out a deficiency with a blood test and check for underlying causes such as absorption problems. Do not start high-dose supplements on suspicion alone — some nutrients are harmful in excess, and supplementing before testing can mask the underlying result.