(See also: RCT at bottom of this page disagrees with this conclusion)
Omega-3 fatty acids and risk of cognitive decline in the elderly: a meta-analysis of randomized controlled trials
Aging Clinical and Experimental Research. May 2015
Xiao-Wei Zhang, Wen-Shang Hou, Min Li, Zhen-Yu Tang
Evidence has demonstrated that omega-3 fatty acids intake may be associated with age-related cognitive decline. However, randomized controlled trials (RCTs) have drawn inconsistent conclusions. We performed a meta-analysis to assess the association between omega-3 fatty acids and risk of cognitive decline in the elderly. A strategic literature search of PubMed, EMBASE, and Cochrane Library (updated to December 2014) was performed. We retrieved six randomized controlled studies as eligible for our meta-analysis.
Among these six studies, the duration time ranged from 3 to 40 months. The dose of omega-3 fatty acids (DHA + EPA) ranged from 400 to 1800 mg. The result of our meta-analysis expressed that omega-3 fatty acids statistically decrease the rate of cognitive decline in MMSE score (WMD = 0.15, [0.05, 0.25]; p = 0.003).
In conclusion, our meta-analysis indicated that omega-3 fatty acids may help to prevent cognitive decline in the elderly.
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No Effect of Omega-3 Fatty Acid Supplementation on Cognition and Mood in Individuals with Cognitive Impairment and Probable Alzheimer’s Disease: A Randomised Controlled Trial
Int. J. Mol. Sci. 2015, 16(10), 24600-24613; doi:10.3390/ijms161024600 Oct 2015
Michelle A. Phillips 1,*, Caroline E. Childs 2, Philip C. Calder 2,3 and Peter J. Rogers 1
1 School of Experimental Psychology, University of Bristol, Bristol BS8 1TU, UK; E-Mail: peter.rogers at bristol.ac.uk
2 Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK; E-Mails: cch at mrc.soton.ac.uk (C.E.C.); pcc at soton.ac.uk (P.C.C.)
3 NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton SO16 6YD, UK
- Author to whom correspondence should be addressed; E-Mail: michelle.brown at bristol.ac.uk; Tel.: +44-117-928-8588; Fax: +44-117-928-8584.
Academic Editors: Cenk Suphioglu and Maurizio Battino
Findings from epidemiological and observational studies have indicated that diets high in omega-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) may reduce the risk of cognitive decline and Alzheimer’s disease (AD). To determine if increasing intake of DHA and EPA through supplementation is beneficial to cognition and mood in individuals with cognitive impairment no dementia (CIND) or Alzheimer’s disease (AD) a four month, randomised, double-blind, placebo controlled study was conducted. Fifty-seven participants with CIND and nineteen with AD were randomised to receive either omega-3 PUFAs (600 mg EPA and 625 mg DHA per day) or placebo (olive oil) over a four month period. Elevating depleted levels of EPA and DHA through supplementation in individuals with CIND or AD was found to have negligible beneficial effect on their cognition or mood. These findings confirm an overall negligible benefit of omega-3 PUFA supplementation for those with cognitive impairment and dementia. More intervention studies need to be undertaken with longer study durations and larger sample sizes. It may prove fruitful to examine effects of different doses as well as effects in other dementia subtypes.