Vitamin therapy and children with Down syndrome: a review of research.

The claim that large doses of vitamin-mineral supplements benefit mentally retarded children has captured the attention of the general public and the medical profession. A study by Harrell, Capp, Davis, Pearless, and Ravitz (1981) reported increases in IQ and improvements in behavior among mentally retarded subjects (one third of whom were children with Down syndrome) receiving nutritional supplementation. However, subsequent studies, focusing exclusively on children with Down syndrome and using less flawed research designs, have demonstrated that vitamin therapy is not useful for members of this population.