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Omega-3 Fatty Acids, Effects on Mental Health

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Full Title: Effects of Omega-3 Fatty Acids on Mental Health

July 2005

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Structured Abstract

Objectives: This report addresses:

  1. The efficacy and safety of omega-3 fatty acids as (primary or supplemental) treatment of psychiatric disorders or conditions (e.g., symptoms alone).
  2. The association between intake of omega-3 fatty acids and the onset, continuation, or recurrence of psychiatric disorders or conditions.
  3. The association between the fatty acid content of biomarkers and the onset, continuation, or recurrence of psychiatric disorders or conditions.

Data Sources: Five databases were searched: MEDLINE®, EMBASE®, Cochrane Central Register of Controlled Trials, PsycInfo, and CAB Health. Additional references was sought through manual searches of included studies' references lists and key review articles, and from the files of content experts.

Review Methods: Studies were considered relevant if they described live human populations of any age, investigated the use of any foods or supplements known to contain omega-3 fatty acids, and utilized mental health outcomes. Data were extracted regarding report, study, population, intervention/exposure, comparator(s), cointerventions, discontinuations (and reasons), and outcomes (i.e., clinical, biomarkers, safety). Study quality (internal validity) and applicability (external validity) were appraised.

Results: Question-specific qualitative syntheses of the evidence were derived. Meta-analysis was conducted with data concerning the supplemental treatment of schizophrenia. Limited numbers of studies addressing the other research questions precluded further meta-analysis. Eighty-six reports, describing 79 studies, were deemed relevant for the systematic review, with each of 6 studies described by more than one report.

A notable safety profile for any type or dose of omega-3 fatty acid supplementation was not observed. Overall, other than for the topics of schizophrenia and depression, few studies were identified. Only with respect to the supplemental treatment of schizophrenia is the evidence even somewhat suggestive of omega-3 fatty acids' potential as short-term intervention. However, these meta-analytic results exclusively pertaining to 2 g/d EPA require replication using design and methods refinements. Additional research might reveal the short- or long-term therapeutic value of omega-3 fatty acids.

Conclusions: Nothing can yet be concluded concerning the clinical utility of omega-3 fatty acids as supplemental treatment for any other psychiatric disorder or condition, or as a primary treatment for all psychiatric disorders or conditions, examined in our review. Primary treatment studies were rare. Because of limited study designs, little is known about the relationship between PUFA biomarker profiles and the onset of any psychiatric disorder or condition. Studies examining the possible association between the intake of omega-3 fatty acids, or the PUFA content of biomarkers, and the continuation or recurrence of psychiatric disorders or conditions were virtually nonexistent.

Future research investigating North Americans populations or those exhibiting a high omega-6/omega-3 fatty acid intake ratio similar to what has been observed in the diet of North Americans will likely be needed. It may behoove researchers to investigate the possible therapeutic or preventive value of the dietary omega-6/omega-3 fatty acid intake ratio.

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Effects of Omega-3 Fatty Acids on Mental Health

Evidence-based Practice Center: University of Ottawa
Topic Nominator: Office of Dietary Supplements, National Institutes of Health

Current as of July 2005


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