Vitamin-mineral supplement fails to improve IQ of mentally retarded young adults.

Twenty mentally retarded persons participated in a study to determine the effect of large doses of vitamin-mineral supplements on IQ, educability, electrophysiological responsiveness, and pyridoxine metabolism. Using a double-blind matched group experimental design, we administered supplements and placebos for 6 months. Pre- and postmeasurements showed no significant effects on any of the measured variables.