Answer: Yes, and here’s why:
Children generally need more nutrient-dense foods in their diets due to the fact that they tend to consume smaller amounts of food at meals. A child's diet may lack essential nutrients for a number of reasons. For example, there are very few natural dietary sources of vitamin D other than fatty fish and liver, which are uncommon in a young child’s diet. Not surprisingly, children tend to avoid nutritious foods. They commonly gravitate toward empty-calorie foods such as cookies, crackers and candy. Eating this type of food generally depresses a child's appetite for healthier foods. Children who do not receive proper levels of all nutrients do not have the full potential to develop and function optimally.
More info
Although vitamin deficiency is uncommon in the United States, insufficiency or marginal deficiency is widespread and could have profound health consequences later in life. Children with substandard daily diets find it difficult to produce academic performance equal to their counterparts who consume diets that come closer to the suggested RDAs. A daily multivitamin and mineral formula (MVM) helps children receive the nutrients their diet may lack. In a well-designed study by Schoenthaler et. al., children using a multivitamin and mineral supplement (MVM) that raised their nutrient intake to the equivalent of a well-balanced diet increased their I.Q. compared to the placebo group by an average of 2.5 points. In one-fifth of the participants, the MVM raised their I.Q. 16 points, presumably because this group of children ate a poorer diet. A very recent study in the British Journal of Nutrition found that 12 weeks of multivitamin and mineral supplementation in normal, healthy 8-14 year-olds significantly improved their cognitive/brain functioning, thus validating the already strong argument for the daily use of a MVM for all but especially during developing years. See our Position on Vitamin and Mineral Supplementation.
Note to parents
Providing your child a daily multivitamin does not decrease the importance of eating healthy foods and establishing good eating patterns, nor can a multivitamin and mineral formula replace the nutritional value of food, but it can supplement a diet lacking essential nutrients. The American Academy of Pediatrics now recommends that infants, children and adolescents obtain 400 international units (IU) of vitamin D every day, which is double the previous recommendation. This guideline is based on recent evidence that children and adolescents may not be getting enough of this vitamin and the occurrence of extreme vitamin D deficiency (rickets) among infants and adolescents in the United States is of particular concern. The safety of giving infants and children 400 IU of vitamin D per day has also been established, and research indicates that getting enough calcium and vitamin D throughout childhood reduces the risk of osteoporosis and other diseases later in life.