Zinc Deficiency in Children with Dyslexia: Concentrations of Zinc and other Minerals in Sweat and Hair

Grant ECG, Howard JMH, Davies S, Chasty H, Hornsby B, Galbraith J Brit. Med. J. 1988;296:607-609 Developmental dyslexia is estimated to affect about 10% of 10 year olds. Studies of mineral concentrations in hair have found that children with impaired learning and those with behaviour disorders tend to have higher concentrations of toxic metals, especially copper, lead and cadmium. Although animal studies have shown that zinc is essential for brain development and function, controversy has arisen about the extent and severity of zinc deficiency in clinical practice because a simple, reliable and sensitive test is not yet in routine use. Sweat zinc concentrations are decreased in zinc deficient states. They may be a more useful guide to clinical zinc deficiency than either hair or serum concentrations. Therefore we compared concentrations of minerals in sweat and hair in children with dyslexia and a control group.