Biochemistry mnemonic; Folate deficiency, Niacin deficiency, Infantile Beriberi symptoms

Folate deficiency: causes

A FOLIC DROP:

Alcoholism
Folic acid antagonists
Oral contraceptives
Low dietary intake
Infection with Giardia
Celiac sprue
Dilatin
Relative folate deficiency
Old
Pregnant

Niacin deficiency: signs and symptoms

The famous 4 D's:

Diarrhoea
Dermatitis
Dementia
Death (if untreated) 

Infantile Beriberi symptoms

Restlessness
Sleeplessness
Breathlessness
Soundlessness (aphonia)
Eatlessness (anorexia)
Great heartedness (dilated heart)