title: Docosahexaenoic acid and adult memory: a systematic review and meta-analysis.
abstract: BACKGROUND
  Subjective memory complaints are common with aging. Docosahexaenoic acid (DHA; 22:6 n-3) is a long-chain polyunsaturated fatty acid (LCPUFA) and an integral part of neural membrane phospholipids that impacts brain structure and function. Past research demonstrates a positive association between DHA plasma status/dietary intake and cognitive function.
  
  
  OBJECTIVE
  The current meta-analysis was designed to determine the effect of DHA intake, alone or combined with eicosapentaenoic acid (EPA; 20:5 n-3), on specific memory domains: episodic, working, and semantic in healthy adults aged 18 years and older. A secondary objective was to systematically review/summarize the related observational epidemiologic literature.
  
  
  METHODS
  A systematic literature search of clinical trials and observational studies that examined the relationship between n-3 LCPUFA on memory outcomes in healthy adults was conducted in Ovid MEDLINE and EMBASE databases. Studies of subjects free of neurologic disease at baseline, with or without mild memory complaints (MMC), were included. Random effects meta-analyses were conducted to generate weighted group mean differences, standardized weighted group mean differences (Hedge's g), z-scores, and p-values for heterogeneity comparing DHA/EPA to a placebo. A priori sub-group analyses were conducted to evaluate the effect of age at enrollment, dose level, and memory type tested.
  
  
  RESULTS
  Episodic memory outcomes of adults with MMC were significantly (P<.004) improved with DHA/EPA supplementation. Regardless of cognitive status at baseline, > 1 g/day DHA/EPA improved episodic memory (P<.04). Semantic and working memory changes from baseline were significant with DHA but no between group differences were detected. Observational studies support a beneficial association between intake/blood levels of DHA/EPA and memory function in older adults.
  
  
  CONCLUSIONS
  DHA, alone or combined with EPA, contributes to improved memory function in older adults with mild memory complaints.
authors.affiliation: Clinical Research, Nutritional Lipids, DSM Nutritional Products, Columbia, Maryland, United States of America.
authors.forename: Karin
authors.initials: K
authors.lastname: Yurko-Mauro
authors.affiliation: Epidemiology, EpidStat Institute, Evergreen, Colorado, United States of America.
authors.forename: Dominik D
authors.initials: DD
authors.lastname: Alexander
authors.affiliation: Scientific Affairs, Van Elswyk Consulting, Inc., Longmont, Colorado, United States of America.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Van Elswyk
mesh_terms: D000328:Adult; D002986:Clinical Trials as Topic; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D004347:Drug Interactions; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D006801:Humans; D008568:Memory / Q000187:drug effects*; D064887:Observational Studies as Topic
chemical_list: D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid