The role of dietary fatty acids in children's behaviour and learning

Three Effective Ways to Nurture Our Brain

Abstract. A growing body of research suggests that physical activity, healthy eating, and music can, either directly or indirectly, have positive effects on our brain and cognition. More specifically, exercising and eating seem to enhance cognitive abilities, such as memory, creativity, and perception. They also improve academic performance and play a protective role from many degenerative diseases, including Alzheimer’s disease. Concerning music, research has shown that there exists a general positive relation between music aptitude and cognitive functioning. Furthermore, the presence of music seems to create a positive mood and a higher arousal, which translates into better performance in many cognitive tasks. This literature review provides an overview of the major empirical findings in this domain. Studies on both healthy and clinical individuals are reviewed and discussed. We conclude with suggestions for educators, policymakers, people in helping professions, and any others interested in making informed decisions about possible ways to nurture their own brain or the brain of the people they are trying to help. We also provide suggestions for additional research on this important topic.

Polyunsaturated fatty acids (PUFAs) for children with specific learning disorders

BACKGROUND

About 5% of school children have a specific learning disorder, defined as unexpected failure to acquire adequate abilities in reading, writing or mathematics that is not a result of reduced intellectual ability, inadequate teaching or social deprivation. Of these events, 80% are reading disorders. Polyunsaturated fatty acids (PUFAs), in particular, omega-3 and omega-6 fatty acids, which normally are abundant in the brain and in the retina, are important for learning. Some children with specific learning disorders have been found to be deficient in these PUFAs, and it is argued that supplementation of PUFAs may help these children improve their learning abilities.

OBJECTIVES

1. To assess effects on learning outcomes of supplementation of polyunsaturated fatty acids (PUFAs) for children with specific learning disorders.2. To determine whether adverse effects of supplementation of PUFAs are reported in these children.

SEARCH METHODS

In November 2015, we searched CENTRAL, Ovid MEDLINE, Embase, PsycINFO, 10 other databases and two trials registers. We also searched the reference lists of relevant articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing PUFAs with placebo or no treatment in children younger than 18 years with specific learning disabilities, as diagnosed in accordance with the fifth (or earlier) edition of theDiagnostic and Statistical Manual of Mental Disorders (DSM-5), or the 10th (or earlier) revision of the International Classification of Diseases (ICD-10) or equivalent criteria. We included children with coexisting developmental disorders such as attention deficit hyperactivity disorder (ADHD) or autism.

DATA COLLECTION AND ANALYSIS

Two review authors (MLT and KHT) independently screened the titles and abstracts of articles identified by the search and eliminated all studies that did not meet the inclusion criteria. We contacted study authors to ask for missing information and clarification, when needed. We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Two small studies involving 116 children, mainly boys between 10 and 18 years of age, met the inclusion criteria. One study was conducted in a school setting, the other at a specialised clinic. Both studies used three months of a combination of omega-3 and omega-6 supplements as the intervention compared with placebo. Although both studies had generally low risk of bias, we judged the risk of reporting bias as unclear in one study, and as high in the other study. In addition, one of the studies was funded by industry and reported active company involvement in the study.None of the studies reported data on the primary outcomes of reading, writing, spelling and mathematics scores, as assessed by standardised tests.Evidence of low quality indicates that supplementation of PUFAs did not increase the risk of gastrointestinal disturbances (risk ratio 1.43, 95% confidence interval 0.25 to 8.15; two studies, 116 children). Investigators reported no other adverse effects.Both studies reported attention deficit hyperactivity disorder (ADHD)-related behaviour outcomes. We were unable to combine the results in a meta-analysis because one study reported findings as a continuous outcome, and the other as a dichotomous outcome. No other secondary outcomes were reported.We excluded one study because it used a cointervention (carnosine), and five other studies because they did not provide a robust diagnosis of a specific learning disorder. We identified one ongoing study and found three studies awaiting classification.

AUTHORS' CONCLUSIONS

Evidence is insufficient to permit any conclusions about the effect of PUFAs on the learning abilities of children with specific learning disorders. Well-designed RCTs with clearly defined populations of children with specific learning disorders who have been diagnosed by standardised diagnostic criteria are needed.

Fish oil improves learning impairments of diabetic rats by blocking PI3K/AKT/nuclear factor-κB-mediated inflammatory pathways

Previous research has demonstrated that diabetes induces learning and memory deficits. However, the mechanism of memory impairment induced by diabetes is poorly understood. Dietary fatty acids, especially polyunsaturated fatty acids, have been shown to enhance learning and memory and prevent memory deficits in various experimental conditions. The present study investigated the effects of fish oil supplementation on the lipid peroxidation, inflammation and neuron apoptosis in the hippocampus of streptozotocin (STZ)-induced diabetes rats. The effects of diabetes and fish oil treatment on the spatial learning and memory were also evaluated using the Morris Water Maze. STZ-induced diabetes impaired spatial learning and memory of rats, which was associated with the inflammation, oxidative stress and apoptosis of hippocampal neurons. Fish oil administration ameliorated cognitive deficit, reduced oxidative stress and tumor necrosis factor α (TNF-α), protected the hippocampal neurons by increasing Protein Kinase B (AKT) phosphorylation and decreasing caspase-9 expression. These results suggested that the principle mechanisms involved in the antidiabetic and neuroprotective effect of fish oil were its antioxidant, anti-inflammatory and anti-apoptosis potential, supporting a potential role for fish oil as an adjuvant therapy for the prevention and treatment of diabetic complications.

Self-reported learning difficulties and dietary intake in Norwegian adolescents

Aim: The academic performance of children impacts future educational attainment which may increase socioeconomic status which again influences their health. One of several factors that might affect academic performance is the diet. The aim of this study was to investigate the cross sectional relation between diet and self-reported reading-, writing-, and mathematical difficulties in Norwegian adolescents. Methods: In total, 475 ninth- and tenth-grade students out of 625 eligible ones from four different secondary schools in three different municipalities in Vest-Agder County, Norway, participated, giving a participation rate of 77%. The students filled in a questionnaire with food frequency questions of selected healthy and unhealthy food items, questions of meal frequency and different learning difficulties. Results: Regular breakfast was significantly associated with decreased odds of both writing and reading difficulties (OR: 0.44 (0.2–0.8), p = 0.01) and mathematical difficulties (OR: 0.33 (0.2–0.6), p ≤ 0.001). In addition, having lunch, dinner and supper regularly were associated with decreased odds of mathematical difficulties. Further, a high intake of foods representing a poor diet (sugar-sweetened soft drinks, sweets, chocolate, savory snacks, pizza and hot dogs) was significantly associated with increased odds of mathematical difficulties. Conclusions: Having a less-frequent intake of unhealthy foods and not skipping meals are associated with decreased odds of self-reported learning difficulties in Norwegian adolescents in this study. The results of this study support the need for a larger study with a more representative sample.

Polyunsaturated fatty acids (PUFAs) for children with specific learning disorders

BACKGROUND

About 5% of schoolchildren have a specific learning disorder, defined as an unexpected failure to acquire adequate abilities in reading, writing or mathematic skills not as a result of reduced intellectual ability, inadequate teaching or social deprivation. Of these, 80% are reading disorders. Polyunsaturated fatty acids (PUFAs), in particular omega-3 and omega-6 fatty acids, which are found abundantly in the brain and retina are important for learning. Some children with specific learning disorders have been found to be deficient in these PUFAs, and it is argued that supplementation of PUFAs may help these children improve their learning abilities.

OBJECTIVES

To assess the effects of polyunsaturated fatty acids (PUFAs) supplementation for children with specific learning disorders, on learning outcomes.

SEARCH METHODS

We searched the following databases in April 2012: CENTRAL (2012, Issue 4), MEDLINE (1948 to April Week 2 2012), EMBASE (1980 to 2012 Week 16), PsycINFO (1806 to April 2012), ERIC (1966 to April 2012), Science Citation Index (1970 to 20 April 2012), Social Science Citation Index (1970 to 20 April 2012), Conference Proceedings Citation Index-Science (1970 to 20 April 2012), Conference Proceedings Citation Index-Social Sciences and Humanites (1970 to 20 April 2012), Cochrane Database of Systematic Reviews (2012, Issue 4), DARE (2012, Issue 2) , ZETOC (24 April 2012) and WorldCat (24 April 2012). We searched the WHO International Clinical Trials Registry Platform and ClinicalTrials.gov on 24 April 2012. We also searched the reference lists of relevant articles identified by the searches.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing polyunsaturated fatty acids (PUFAs) with placebo or no treatment in children aged below 18 years with specific learning disabilities diagnosed using DSM-IV, ICD-10 or equivalent criteria. We intended to include participants with co-existing developmental disorders such as attention deficit hyperactivity disorder (ADHD) or autism.

DATA COLLECTION AND ANALYSIS

Two authors (ML and KH) independently screened the titles and abstracts of the search results and eliminated all studies that did not meet the inclusion criteria. Authors were contacted for missing information and clarifications when needed.

MAIN RESULTS

We did not find any studies suitable for inclusion in the review. One study is awaiting classification as we were unable to get any information from the study author.

AUTHORS' CONCLUSIONS

There is insufficient evidence to draw any conclusion about the use of PUFAs for children with specific learning disorders. There is a need for well designed randomised studies to support or refute the use of PUFAs in this group of children.

Fish oil supplementation and physical exercise program: distinct effects on different memory tasks

Both fish oil supplementation and physical exercise are able to induce benefits to mental health by providing an improvement in cognitive performance and enhancing neuroplasticity and protection against neurological lesions. The aim of the present study was to investigate the cognitive effects in rats of the: (1) a diary and prolonged fish oil supplementation (85 mg/kg/day) initiated from prenatal period to the midlife (300 day/old); (2) moderate physical exercise in treadmill initiated from adolescent period to midlife and (3) association of fish oil supplementation and moderate physical exercise protocol during the same period. Animals were submitted to the habituation in the open-field, object recognition and to the plus-maze discriminative avoidance tasks. Our results demonstrated that a diary and prolonged fish oil supplementation can facilitate the persistence of the long-term habituation and recognition memories without, however, affecting the discriminative avoidance memory. Conversely, although the program of physical exercise exerted no effects on habituation or objects recognition, it was able to potentiate the persistence of the discriminative avoidance memory. Such promnestic effects (induced by both fish oil supplementation and physical exercise) were not accompanied by alterations in emotionality or locomotor activity. Our findings suggest that fish oil supplementation, initiated from prenatal period to midlife, and physical exercise program applied throughout the life induced distinctly a better cognitive performance.

Dietary omega-3 fatty acid supplementation for optimizing neuronal structure and function

Direct actions of omega-3 polyunsaturated fatty acids (PUFAs) on neuronal composition, neurochemical signaling and cognitive function constitute a multidisciplinary rationale for classification of dietary lipids as "brain foods." The validity of this conclusion rests upon accumulated mechanistic evidence that omega-3 fatty acids actually regulate neurotransmission in the normal nervous system, principally by modulating membrane biophysical properties and presynaptic vesicular release of classical amino acid and amine neurotransmitters. The functional correlate of this hypothesis, that certain information processing and affective coping responses of the central nervous system are facilitated by bioavailability of omega-3 fatty acids, is tentatively supported by developmental and epidemiological evidence that dietary deficiency of omega-3 fatty acids results in diminished synaptic plasticity and impaired learning, memory and emotional coping performance later in life. The present review critically examines available evidence for the promotion in modern society of omega-3 fatty acids as adaptive neuromodulators capable of efficacy as dietary supplements and as potential prophylactic nutraceuticals for neurological and neuropsychiatric disorders.

Omega-3 fatty acids: a comprehensive review of their role in health and disease

Omega-3 fatty acids (omega-3 FAs) are essential fatty acids with diverse biological effects in human health and disease. Reduced cardiovascular morbidity and mortality is a well-established benefit of their intake. Dietary supplementation may also benefit patients with dyslipidaemia, atherosclerosis, hypertension, diabetes mellitus, metabolic syndrome, obesity, inflammatory diseases, neurological/ neuropsychiatric disorders and eye diseases. Consumption of omega-3 FAs during pregnancy reduces the risk of premature birth and improves intellectual development of the fetus. Fish, fish oils and some vegetable oils are rich sources of omega-3 FAs. According to the UK Scientific Advisory Committee on Nutrition guidelines (2004), a healthy adult should consume a minimum of two portions of fish a week to obtain the health benefit. This review outlines the health implications, dietary sources, deficiency states and recommended allowances of omega-3 FAs in relation to human nutrition.

Mouse models of Rett syndrome: from behavioural phenotyping to preclinical evaluation of new therapeutic approaches

Rett syndrome (RTT) is a neurodevelopmental disorder, primarily affecting girls. RTT causes severe cognitive, social, motor and physiological impairments and no cure currently exists. The discovery of a monogenic origin for RTT and the subsequent generation of RTT mouse models provided a major breakthrough for RTT research. Although the characterization of these mutant mice is far from complete, they recapitulate several RTT symptoms. This review provides an overview of the behavioural domains so far investigated in these models, including the very few mouse data concerning the developmental course of RTT. Both clinical and animal studies support the presence of early defects and highlight the importance of probing the presymptomatic phase for both the precocious identification of biomarkers and the early assessment of potential therapies. Preclinical evaluations of pharmacological and nonpharmacological interventions so far carried out are also illustrated. In addition, genetic manipulations are reported that demonstrate rescue from the damage caused by the absence of the methyl-CpG-binding protein 2 (MeCP2) gene even at a mature stage. Given the rare occurrence of RTT cases, transnational collaborative networks are expected to provide a deeper understanding of aetiopathology and the development of new therapeutic approaches.

Brain foods: the effects of nutrients on brain function

It has long been suspected that the relative abundance of specific nutrients can affect cognitive processes and emotions. Newly described influences of dietary factors on neuronal function and synaptic plasticity have revealed some of the vital mechanisms that are responsible for the action of diet on brain health and mental function. Several gut hormones that can enter the brain, or that are produced in the brain itself, influence cognitive ability. In addition, well-established regulators of synaptic plasticity, such as brain-derived neurotrophic factor, can function as metabolic modulators, responding to peripheral signals such as food intake. Understanding the molecular basis of the effects of food on cognition will help us to determine how best to manipulate diet in order to increase the resistance of neurons to insults and promote mental fitness.

Nutritional factors in a mouse model of Rett syndrome

Environmental factors such as nutrition and housing can influence behavioral and anatomical characteristics of several neurological disorders, including Rett syndrome (RTT). RTT is associated with mutations in the X-linked gene encoding MeCP2, a transcriptional repressor that binds methylated DNA. While direct genetic intervention in humans is impossible at this time, motor and cognitive deficits in RTT may be ameliorated through manipulations of epigenetic/environmental factors. For example, studies in rodents suggest that choline nutrient supplementation during critical periods of brain development enhances cholinergic neurotransmission, alters neuronal size and distribution, and facilitates performance of memory and motoric tasks. Recent work in a mouse model of RTT shows that enhancing maternal nutrition through choline supplementation improves both anatomical and behavioral symptoms in the mutant offspring. We describe here cellular and molecular mechanisms that may underlie this specific enhancement and may provide more general insights into mechanisms underlying gene-environment interactions in neurological disorders.