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 production in extreme northern and southern latitudes. Rates of vitamin D deficiency are higher among people with untreated celiac disease, inflammatory bowel disease, exocrine pancreatic insufficiency from cystic fibrosis, and short bowel syndrome, which can all produce problems of malabsorption. Vitamin D deficiency is also more common after surgical procedures that reduce absorption from the intestine, including weight loss procedures. Vitamin D deficiency is associated with increased mortality in critical illness. People who take vitamin D supplements before being admitted for intensive care are less likely to die than those who do not take vitamin D supplements. Additionally, vitamin D