Breast-feeding and cognitive development: A meta-analysis
ABSTRACT Although the results of many clinical studies suggest that breast-fed children score higher on tests of cognitive function than do formula-fed children, some investigators have suggested that these differences are related to confounding covariables such as socioeconomic status or maternal education.
Our objective was to conduct a meta-analysis of observed differences in cognitive development between breast-fed and formula-fed children.
In this meta-analysis we defined the effect estimate as the mean difference in cognitive function between breast-fed and formula-fed groups and calculated average effects using fixed-effects and random-effects models.
Of 20 studies meeting initial inclusion criteria, 11 studies controlled for >/=5 covariates and presented unadjusted and adjusted results. An unadjusted benefit of 5.32 (95% CI: 4.51, 6.14) points in cognitive function was observed for breast-fed compared with formula-fed children. After adjustment for covariates, the increment in cognitive function was 3.16 (95% CI: 2.35, 3.98) points. This adjusted difference was significant and homogeneous. Significantly higher levels of cognitive function were seen in breast-fed than in formula-fed children at 6-23 mo of age and these differences were stable across successive ages. Low-birth-weight infants showed larger differences (5.18 points; 95% CI: 3.59, 6.77) than did normal-birth-weight infants (2.66 points; 95% CI: 2.15, 3.17) suggesting that premature infants derive more benefits in cognitive development from breast milk than do full-term infants. Finally, the cognitive developmental benefits of breast-feeding increased with duration.
This meta-analysis indicated that, after adjustment for appropriate key cofactors, breast-feeding was associated with significantly higher scores for cognitive development than was formula feeding.
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ABSTRACT: The proposal that dietary docosahexaenoic acid (DHA) enhances neurocognitive functioning in term infants is controversial. Theoretical evidence, laboratory research and human epidemiological studies have convincingly demonstrated that DHA deficiency can negatively impact neurocognitive development. However, the results from randomized controlled trials (RCTs) of DHA supplementation in human term-born infants have been inconsistent. This article will (i) discuss the role of DHA in the human diet, (ii) explore the physiological mechanisms by which DHA plausibly influences neurocognitive capacity, and (iii) seek to characterize the optimal intake of DHA during infancy for neurocognitive functioning, based on existing research that has been undertaken in developed countries (specifically, within Australia). The major observational studies and RCTs that have examined dietary DHA in human infants and animals are presented, and we consider suggestions that DHA requirements vary across individuals according to genetic profile. It is important that the current evidence concerning DHA supplementation is carefully evaluated so that appropriate recommendations can be made and future directions of research can be strategically planned.Frontiers in Human Neuroscience 11/2013; 7:774. DOI:10.3389/fnhum.2013.00774 · 2.90 Impact Factor
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ABSTRACT: Maternal care involves the consistent and coordinated expression of a variety of behaviours over an extended period of time, and adverse changes in maternal care can have profound impacts on the CNS and behaviour of offspring. This complex behavioural pattern depends on a number of integrated neuroendocrine mechanisms. This review will discuss the use of animal models in the study of the role of maternal care in shaping CNS function, the contributions of corticosteroid releasing hormone, vasopressin, oxytocin, and prolactin in this process, the molecular mechanisms involved, and the translational relevance of this research.Neuropeptides 10/2013; DOI:10.1016/j.npep.2013.10.013 · 2.55 Impact Factor
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ABSTRACT: Nutrition is crucial to the initial development of the central nervous system (CNS), and then to its maintenance, because both depend on dietary intake to supply the elements required to develop and fuel the system. Diet in early life is often seen in the context of "programming" where a stimulus occurring during a vulnerable period can have long-lasting or even lifetime effects on some aspect of the organism's structure or function. Nutrition was first shown to be a programming stimulus for growth, and then for cognitive behavior, in animal studies that were able to employ methods that allowed the demonstration of neural effects of early nutrition. Such research raised the question of whether nutrition could also programme cognition/brain structure in humans. Initial studies of cognitive effects were observational, usually conducted in developing countries where the presence of confounding factors made it difficult to interpret the role of nutrition in the cognitive deficits that were seen. Attributing causality to nutrition required randomized controlled trials (RCTs) and these, often in developed countries, started to appear around 30 years ago. Most demonstrated convincingly that early nutrition could affect subsequent cognition. Until the advent of neuroimaging techniques that allowed in vivo examination of the brain, however, we could determine very little about the neural effects of early diet in humans. The combination of well-designed trials with neuroimaging tools means that we are now able to pose and answer questions that would have seemed impossible only recently. This review discusses various neuroimaging methods that are suitable for use in nutrition studies, while pointing out some of the limitations that they may have. The existing literature is small, but examples of studies that have used these methods are presented. Finally, some considerations that have arisen from previous studies, as well as suggestions for future research, are discussed.Frontiers in Human Neuroscience 08/2013; 7:445. DOI:10.3389/fnhum.2013.00445 · 2.90 Impact Factor