Dyslexia and learning difficulties
From The Nutritional Health Bible by Linda Lazarides (1997). This free database is provided for interest only. Linda's later writings refer to more up-to-date research.
Some causative factors- Essential fatty acid deficiency
- Food intolerance
- Heavy metal toxicity
- Vitamin deficiencies
- Zinc and other mineral deficiencies
Grant EC et al: Zinc deficiency in children with dyslexia: concentrations of zinc and other minerals in sweat and hair. Br Med J: Clin Res 296(6622):607-9, 1988.
There is a steady accumulation of evidence that iron deficiency limits physical performance, reduces work productivity and impairs cognitive (thinking) processes. In children it leads to lower mental developmental test scores, failure to respond to test stimuli, short attention span, unhappiness, and increased fearfulness and tension. Lozoff B: Iron and learning potential in childhood. Bull NY Acad Med 65(10):1050-66, 1989.
An analysis of the literature confirms that exposure to lead in small amounts impairs children's IQ. Needleman HL et al: Low-level lead exposure and the IQ of children. a meta-analysis of modern studies. JAMA 263(5):673-8, 1990.
Young adults who had had higher lead levels in milk teeth shed at ages 6 or 7 were still more likely to have a reading disability, lower vocabulary, poorer co-ordination and longer reaction times than those with lower levels. Needleman HL et al: The long-term effects of exposure to low levels of lead in childhood. An 11-year follow-up report. N Engl J Med 322(2):83-8, 1990.
Zinc, calcium, lead and cadmium status was assessed from hair samples in 146 children aged 5-16, and measures of cognitive function were collected. Higher zinc levels appeared to protect against the harmful effects of cadmium on verbal IQ and reading performance. Higher calcium levels seemed to protect against harmful lead effects on performance IQ. Lester ML et al: Protective effects of zinc and calcium against heavy metal impairment of children's cognitive function. Nutrition and Behaviour 3:145-61, 1986.
Behaviour, learning and health problems were compared between boys with high and low intakes of essential fatty acids. More behavioral problems were found in those with lower omega-3 intakes, and more learning and health problems were found in those with lower omega-6 intakes. Stevens LJ et al: Omega-3 fatty acids in boys with behavior, learning and health problems. Physiol Behav 59(4-5):915-20, 1996.
Promising nutritional researchOf 27 pupils with learning problems, 18 showed a rise of 1-5 and 6 showed a rise of 6-15 points in their IQ after beginning a food elimination and replacement programme free of sugar and refined foods. Hyperactivity was reduced and behaviour and concentration as assessed by the teachers improved. Borok G et al: Atopy: the incidence in chronic recurrent maladies. XVI European Congress of Allergology and Clinical Immunology, Madrid, 1995.
127 young adults took either 10 times the RDA of 9 vitamins, or a placebo, in a double-blind trial. After 12 months better performance on two measures of attention was found in the women only. Benton D et al: The impact of long-term vitamin supplementation on cognitive functioning. Psychopharmacology 117(3):298-305, 1995.
A multivitamin/mineral preparation or placebo was administered double-blind for 8 months, resulting in a significant increase in non-verbal intelligence. Benton D et al: Effect of vitamin and mineral supplementation on intelligence of a sample of schoolchildren. Lancet Jan 23:140-143, 1988.