No abstract

This review considers the research to date on the role of nutrition in cognitive development in children, with a particular emphasis on the relatively neglected post-infancy period. Undernutrition and deficiencies of iodine, iron, and folate are all important for the development of the brain and the emergent cognitive functions, and there is some evidence to suggest that zinc, vitamin B12, and omega-3 polyunsaturated fatty acids may also be important. Considerations for future research include a focus on the interactions between micronutrients and macronutrients that might be influential in the optimization of cognitive development; investigation of the impact of nutritional factors in children after infancy, with particular emphasis on effects on the developing executive functions; and selection of populations that might benefit from nutritional interventions, for example, children with nutrient deficiencies or those suffering from attention deficit-hyperactivity disorder and dyslexia.

The pattern of normal foetal brain development has been described for the Merino sheep. Controlled flock matings were used and foetuses removed by hysterotomy at 40, 54, 67, 81, 90, 95, 109, 121 and 150 days of gestation. Lambs at 7 days after birth and adults were also studied. The CNS was dissected, separated and weighed as four segments--cerebral hemispheres, brain stem, cerebellum and spinal cord. Determinations of DNA, RNA, protein, cholesterol and water content were subsequently carried out on each segment. Brain weight increased from 0.264 g (40 days) to 52.74 g at 150 days. The ratio to body weight decreased from 6.7% (40 days) to 1.5% (150 days). DNA increased more rapidly from 40 to 90 days in the cerebral hemispheres and brain stem than in the cerebellum and spinal cord and this increase preceded the main increase in weight. Increases in cholesterol and decreases in water content were also more marked in the cerebral hemispheres and brain stem. Increase in brain weight occurred in two phases, one up to 90 days followed by a more rapid and larger increase after 90 days which continued to birth. These two phases appear to reflect an increase in neuroblast multiplication followed by neuroglial multiplication and myelination respectively. At birth, brain weight had reached 50% of adult size, the cerebral hemispheres 52% of adult size, the cerebellum 40% and spinal cord 40%. The relative maturity of the brain at birth justifies the classification of the sheep as a prenatal brain developer.

In a population-based case-control study carried out in Adelaide, South Australia, during the years 1984-1987, the diets of 104 cases of cancer of the pancreas 1 year prior to diagnosis were compared with the diets of 253 community controls. A quantitative food-frequency questionnaire was used to assess usual dietary intakes of 179 food items. Cases were compared with controls in terms of both the amounts of individual food items consumed and the estimated contributions of 48 nutrients to the diet. Food items consumed more by cases than controls included boiled eggs and omelettes as well as a number of items that could be collectively described as sweet and fatty. Food items consumed less by cases than controls included several vegetables and fruits. Conditional logistic regression analysis of nutrient intake adjusted for total energy and for alcohol and tobacco usage yielded an estimate of relative risk of 3.19, with a 95% confidence interval of 1.58-6.47 for the highest quartile of cholesterol intake (relative to the lowest quartile). For the top quartile of refined sugar intake, the estimated relative risk was 2.21 (95% confidence interval 1.07-4.55). Several nutrients derived principally from plant foods were statistically significantly associated with lower risks. Alcohol consumption was significantly lower among cases than controls. Current smokers had a relative risk of 1.76 (95% confidence interval 0.93-3.34) relative to those who had never smoked. There was no association of pancreatic cancer with coffee drinking.