A child's diet should be enough for him or her to get all the vitamins and minerals he or she needs while eating balanced meals regularly. However, some children, such as picky eaters, kids with chronic illness, vegetarians, or particularly active children, might need vitamins in certain cases. Consult with a pediatrician about which vitamins your child might be missing in his or her diet and choose a supplement accordingly. Pay close attention to the levels of vitamins A, B, C, and D, as well as calcium and iron, as these are widely regarded as the most important for development and growth.
Deficiencies of vitamins are classified as either primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a "lifestyle factor", such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of 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 .