Vitamin deficiency and vitamin K deficiency. In the medical literature, any of these may also be called by names on the pattern of "hypovitaminosis" or "avitaminosis" + "[letter of vitamin]", for example, hypovitaminosis A, hypovitaminosis C, hypovitaminosis D. Conversely hypervitaminosis is the syndrome of symptoms caused by over-retention of fat-soluble vitamins in the body. Vitamin deficiency A vitamin deficiency can cause a disease or syndrome known as an avitaminosis or hypovitaminosis. This usually refers to a long-term deficiency of a vitamin. When caused by inadequate nutrition it can be classed as a "primary deficiency", and when due to an underlying disorder such
Vitamin B12 deficiency Vitamin B12 deficiency Vitamin B deficiency, also known as cobalamin deficiency, is the medical condition of low blood levels of vitamin B. In mild deficiency a person may feel tired and have a reduced number of red blood cells (anemia). In moderate deficiency there may be inflammation of the tongue and the beginning of neurological problems including abnormal sensations such as "pins and needles", while severe deficiency may include reduced heart function and greater neurological problems. Neurological problems may include changes in reflexes, poor muscle function, memory problems, decreased taste, and in extreme cases psychosis. Sometimes temporary infertility may also