Megavitamin Treatment of Mental Retardation in Children: A Review of Effects on Behavior and Cognition

Abstract

Many forms of vitamin supplementation have been proposed for the treatment of behavioral and cognitive disorders in children with mental retardation. Except for nutrient deficiencies and selected inborn errors of metabolism, the efficacy of these treatments has not been established. Therapeutic supplementation with vitamin B(6) in Down syndrome and folie acid in fragile X syndrome was attempted following the identification of apparent biochemical aberrations involving the nutrients. Double-blind controlled trials have revealed no evidence that B(6) treatment was effective in Down syndrome. Very limited evidence, only among prepubertal subjects, suggested that behaviors improved with folie acid treatment in fragile X syndrome. There is less clarity of the scientific rationales for various combinations of vitamins (or vitamins and minerals) that have been promoted according to the concept of orthomolecular medicine. Well-designed controlled studies, with data presented in conformity with generally accepted scientific standards, have not supported the efficacy of megadose supplementation with 1) multivitamins in cognitive disabilities or attention deficit disorders, or 2) multivitamins and minerals in Down syndrome or other forms of mental retardation. Insufficient data are available to support claims made for vitamin B(6) and magnesium supplementation in autism. Research in the larger field of nutrient-behavior research has reinforced the need for studies to be more rigorously designed and to draw on the expertise of multiple disciplines. Evidence of toxic effects of nutrients continues to accrue, reinforcing the fact that megadoses should not be used indiscriminately or without physician monitoring. For children with mental retardation generally, assuring that established nutritional needs are met warrants primary consideration.

Personalized Management of Selected Neurological Disorders

“…In 1981, Harrell et al [211] reported that the administration of a megavitamin mineral supplement to a heterogenous group of 16 mentally retarded children, 4 of which had DS, had led to encouraging results. However, controlled double-blind studies on somewhat larger groups using similar megadoses of vitamins and minerals but no thyroid supplementation did not result in any beneficial effects [212][213][214][215][216]. However, these studies were devoid of a detailed theory of the mechanism of action, and the age distribution of the patients was disadvantageous in relation to possible targets in the developing brains.…”

Controversial Practices

“…Vitamin supplementation has been proposed for numerous behavioral and cognitive disorders in children with mental retardation. A review of the literature has shown that vitamin B6 was ineffective in treating children with Down syndrome, folic acid treatment had very limited effects on some children with fragile X syndrome, megadose multivitamin supplements have not been effective with cognitive disorders or attention-deficit disorders, and multivitamins and minerals have not been effective with Down syndrome or other forms of mental retardation (Kozlowski, 1992). To judge the efficacy of diets requires an examination of the primary sources (i.e., the original studies), but the controversy has arisen because of people's interpretations of the pros and cons of a practice.…”