A deficiency of the B vitamin nicotinic acid (niacin), marked by weakness, gastrointestinal disturbances, skin disorders, and neurological symptoms, such as apathy, confusion, disorientation, and neuritis.

Pellagra

According to the APA, dementia is a generalized, pervasive deterioration of memory and at least one other cognitive function, such as language and an executive function, due to a variety of causes. The loss of intellectual abilities is severe enough to interfere with an individual’s daily functioning and social and occupational activity.

Dementia

Deficiency in niacin (vitamin B3), is said to cause Pellagra with dementia as a result.

Saint Louis University

Highest impairments in cognition are caused by deficiencies in:
- Vitamin B12
- Thiamine
- Folic Acid 
- Niacin

Vitamin Deficiencies & Mental Health

Adan, R. A., van der Beek, E. M., Buitelaar, J. K., Cryan, J. F., Hebebrand, J., Higgs, S., ... & Dickson, S. L. (2019). Nutritional psychiatry: Towards improving mental health by what you eat. European Neuropsychopharmacology, 29(12), 1321-1332.

Nutrition Psychiatry: Towards Improving Mental Health by What You Eat

Stated by researchers to cause: 
- Fatigue
- Lethargy 
- Depression
- Poor memory 
- & is associated with mania and psychosis

Vitamin B12 Deficiency

Deficiency in thiamine (vitamin B1), is stated by researchers to cause beriberi with numbness as CNS symptom (which disrupts motor functioning) as well as Wernicke’s encephalopathy.

Thiamine Deficiency

According to researchers, folic acid (vitamin B9) deficiency has detrimental effects on neurodevelopment in utero and in infancy; and deficits are associated with a greater risk of depression during adulthood.

Learn Before

Related

Learn After