Skip to content
Deals

Omega-3 (DHA and EPA) and memory: grade C

Limited evidence. Direction: Benefit.

Educational guidance, not medical advice

Why this grade

Rubric condition met: Results mainly in older adults with memory complaints being extrapolated to healthy adults, plus one RCT in young adults with low DHA intake; pooled estimates mixed

Alex 2020 found a mild memory benefit (g = 0.31) in non-demented adults, but Mazereeuw 2012 found no effect on composite memory in healthy subjects. Positive trials are in older adults with memory complaints or below-age-norm memory (MIDAS, Martek-affiliated) or small (n = 44), and the memory meta-analysis was written by DSM-employed or DSM-paid authors. A 12-month fish oil plus cocoa trial in older adults with memory complaints was null. In young adults with low habitual DHA intake, one 6-month RCT (Stonehouse 2013, n = 176, 1.16 g DHA/d, funding not stated in the record) found faster reaction times on episodic and working memory tasks, with effects that differed by sex; Cooper 2015 found improved short-term memory in a low n-3 status subgroup, and an exploratory MAPT analysis in adults aged 70+ with a low omega-3 index found a difference on one verbal fluency test only.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)2010201520202025Meta-analysisRCTDouble-blind plac…Yurko-Mauro 2010, 2010: RCT, n = 485, result not recordedVauzour 2023, 2023: RCT, n = 259, result not recordedHooper 2017, 2017: RCT, n = 183, result not recordedStonehouse 2013, 2013: RCT, n = 176, result not recordedImpact of Omega-3 Fatty 2016, 2016: double-blind placebo-controlled proof-of-concept trial (26 weeks), n = 44, result not recordedYurko-Mauro 2015, 2015: meta-analysis, n not recorded, result not recordedMazereeuw 2012, 2012: meta-analysis, n not recorded, result not recordedCooper 2015, 2015: meta-analysis, n not recorded, result not recordedAlex 2020, 2020: meta-analysis, n not recorded, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Yurko-Mauro 20102010RCT485result not recorded
Mazereeuw 20122012meta-analysisnot recordedresult not recorded
Stonehouse 20132013RCT176result not recorded
Yurko-Mauro 20152015meta-analysisnot recordedresult not recorded
Cooper 20152015meta-analysisnot recordedresult not recorded
Impact of Omega-3 Fatty 20162016double-blind placebo-controlled proof-of-concept trial (26 weeks)44result not recorded
Hooper 20172017RCT183result not recorded
Alex 20202020meta-analysisnot recordedresult not recorded
Vauzour 20232023RCT259result not recorded

Cognitive Changes with Omega-3 Polyunsaturated Fatty Acids in Non-Demented Older Adults with Low Omega-3 Index.

Hooper C, De Souto Barreto P, Coley N. Cognitive Changes with Omega-3 Polyunsaturated Fatty Acids in Non-Demented Older Adults with Low Omega-3 Index J Nutr Health Aging, 2017. PMID 29083439

Result not recorded
Design
Secondary exploratory analysis of a randomized placebo-controlled trial (MAPT), 3 years
Sample
n = 183
Population
Adults aged 70 or over with subjective memory complaints and a low omega-3 index
Funding
not stated

A combined DHA-rich fish oil and cocoa flavanols intervention does not improve cognition or brain structure in older adults with memory complaints: results from the CANN randomized, controlled parallel-design study.

Vauzour D, Scholey A, White DJ. A combined DHA-rich fish oil and cocoa flavanols intervention does not improve cognition or brain structure in older adults with memory complaints: results from the CANN randomized, controlled parallel-design study Am J Clin Nutr, 2023. PMID 37315924

Result not recorded
Design
Randomized placebo-controlled trial (12 months), fish oil combined with cocoa flavanols
Sample
n = 259
Population
Older adults with subjective or mild cognitive impairment (clinical population)
Funding
University of Illinois Urbana-Champaign; Abbott Nutrition; Lundbeck Foundation (Crossref/Europe PMC)

Impact of Omega-3 Fatty Acid Supplementation on Memory Functions in Healthy Older Adults.

Külzow N, Witte AV, Kerti L. Impact of Omega-3 Fatty Acid Supplementation on Memory Functions in Healthy Older Adults J Alzheimers Dis, 2016. PMID 26890759

Result not recorded
Design
Double-blind placebo-controlled proof-of-concept trial (26 weeks)
Sample
n = 44
Population
Cognitively healthy adults aged 50-75
Funding
not stated

DHA supplementation improved both memory and reaction time in healthy young adults: a randomized controlled trial.

Stonehouse W, Conlon CA, Podd J. DHA supplementation improved both memory and reaction time in healthy young adults: a randomized controlled trial Am J Clin Nutr, 2013. PMID 23515006

Result not recorded
Design
Randomized, placebo-controlled, double-blind trial (6 months)
Sample
n = 176
Population
Healthy nonsmoking adults aged 18-45 with low habitual DHA intake
Funding
not stated

Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline.

Yurko-Mauro K, McCarthy D, Rom D. Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline Alzheimers Dement, 2010. PMID 20434961

Result not recorded
Design
Randomized, double-blind, placebo-controlled trial at 19 US sites (24 weeks)
Sample
n = 485
Population
Healthy adults aged 55 and over with age-related cognitive decline (memory scores below younger adults)
Funding
not stated in PubMed or Crossref record

Docosahexaenoic acid and adult memory: a systematic review and meta-analysis.

Yurko-Mauro K, Alexander DD, Van Elswyk ME. Docosahexaenoic acid and adult memory: a systematic review and meta-analysis PLoS One, 2015. PMID 25786262

Result not recorded
Design
Systematic review and meta-analysis of trials, plus review of observational studies
Population
Healthy adults aged 18 and older, with or without mild memory complaints
Funding
not stated; see COI

Effects of ω-3 fatty acids on cognitive performance: a meta-analysis.

Mazereeuw G, Lanctôt KL, Chau SA. Effects of ω-3 fatty acids on cognitive performance: a meta-analysis Neurobiol Aging, 2012. PMID 22305186

Result not recorded
Design
Meta-analysis of 10 randomized double-blind placebo-controlled trials
Population
Healthy adults, adults with cognitive impairment no dementia, and people with Alzheimer's disease
Funding
Canadian Institutes of Health Research

Omega-3 polyunsaturated fatty acid supplementation and cognition: A systematic review and meta-analysis.

Cooper RE, Tye C, Kuntsi J. Omega-3 polyunsaturated fatty acid supplementation and cognition: A systematic review and meta-analysis J Psychopharmacol, 2015. PMID 26040902

Result not recorded
Design
Systematic review and meta-analysis of 24 RCTs
Population
Healthy adults and school-aged children, plus children with ADHD and related disorders
Funding
not stated

Long-chain omega-3 polyunsaturated fatty acids and cognitive decline in non-demented adults: a systematic review and meta-analysis.

Alex A, Abbott KA, McEvoy M. Long-chain omega-3 polyunsaturated fatty acids and cognitive decline in non-demented adults: a systematic review and meta-analysis Nutr Rev, 2020. PMID 31841161

Result not recorded
Design
Systematic review and meta-analysis of 25 RCTs (PROSPERO CRD42017078664)
Population
Non-demented adults, including people with mild cognitive impairment
Funding
International Postgraduate Research Scholarship (Crossref funder)

Search and history

Search (): (omega-3[ti] OR docosahexaenoic[ti] OR DHA[ti]) AND (memory[ti]) AND (meta-analysis[pt] OR systematic review[pt])

  • Graded C (awaiting approval)
  • C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page