Vitamin the vitamin. People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency. In contrast, restrictive diets have the potential to cause prolonged vitamin deficits, which may result in often painful and potentially deadly diseases. Well-known human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra), vitamin C (scurvy), and vitamin D (rickets). In much of the developed world, such deficiencies are rare; this is due to (1) an adequate supply of food and (2) the addition of vitamins and minerals to common foods (fortification). In addition to these classical vitamin deficiency diseases, some evidence has also suggested
Vitamin D deficiency the metabolism of vitamin D, causing a deficiency. Some types of liver diseases and kidney diseases can decrease vitamin D production leading to a deficiency. The liver is required to transform vitamin D into 25-hydroxyvitamin D. This is an inactive metabolite of vitamin D but is a necessary precursor (building block) to create the active form of vitamin D. In liver disease, the 25-hydroxyvitamin D may not be formed, leading to a vitamin D deficiency. The kidneys are responsible for converting 25-hydroxyvitamin D to 1,25-hydroxyvitamin D. This is the active form of vitamin D in the body. Kidney disease often