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 D deficiency D levels falling within this normal range prevent clinical manifestations of vitamin D insufficiency as well as vitamin D toxicity from taking in too much vitamin D. Vitamin D deficiency can be asymptomatic, but may also cause several problems including: Vitamin D deficiencies are often caused by decreased exposure of the skin to sunlight. People with a darker pigment of skin or increased amounts of melanin in their skin may have decreased production of Vitamin D. Melanin absorbs ultraviolet B radiation from the sun and reduces vitamin D production. Sunscreen can also reduce vitamin D production. Medications may speed up