RESUMO
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.
RESUMO
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.