Vitamin deficiencies

Vitamin A deficiency (VAD) or hypovitaminosis A is a lack of vitamin A in blood and tissues.

Beriberi refers to a cluster of symptoms caused primarily by thiamine (vitamin B1) deficiency.

Pellagra is a vitamin deficiency disease most frequently caused by a chronic lack of niacin (vitamin B3 or vitamin PP, from pellagra-preventing factor) in the diet.

Korsakoff's syndrome is a manifestation of Wernicke's encephalopathy, also called Wernicke's disease.

Rickets is defective mineralization or calcification of bones before epiphyseal closure in immature mammals due to deficiency or impaired metabolism of vitamin D, phosphorus or calcium, potentially leading to fractures and deformity.

Vitamin E deficiency or hypovitaminosis E is a deficiency of vitamin E.

Bitot's spots are the buildup of keratin located superficially in the conjunctiva, which are oval, triangular or irregular in shape.

Biotin deficiency is a rare nutritional disorder which can become serious, even fatal, if allowed to progress untreated.

Vitamin B12 deficiency, also known as hypocobalaminemia, refers to low blood levels of vitamin B12.

Vitamin D deficiency, or Hypovitaminosis D, can result from inadequate nutritional intake of vitamin D and/or inadequate sunlight exposure (in particular sunlight with adequate ultraviolet B rays), disorders limiting vitamin D absorption, and conditions impairing vitamin D conversion into active metabolites—including certain liver, kidney, and hereditary disorders.

A vitamin deficiency can cause a disease or syndrome known as an avitaminosis or hypovitaminosis.

Folate deficiency is a low level of folic acid in the body.

Vitamin K deficiency or hypovitaminosis K is a form of avitaminosis resulting from insufficient vitamin K1 or vitamin K2 or both.

Wernicke's encephalopathy (or Wernicke's disease) refers to the presence of neurological symptoms caused by biochemical lesions of the central nervous system after exhaustion of B-vitamin reserves, in particular thiamine (vitamin B1).