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 further increasing the risk of fall and bone fractures in adults. Ultraviolet B rays from sunlight is a large source of vitamin D. Fatty fish such as salmon, herring, and mackerel are also sources of vitamin D. Milk is often fortified with vitamin D and sometimes bread, juices, and other dairy products are fortified with vitamin D as well. Many multivitamins now contain vitamin D in different amounts. Vitamin D deficiency is typically diagnosed by measuring the concentration of the 25-hydroxyvitamin D in the blood, which is the most accurate measure of stores of vitamin D in the body. Vitamin