Food and Behaviour Research

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

Stonehouse W, Conlon CA, Podd J, Hill SR, Minihane AM, Haskell C, Kennedy D. (2013) Am J Clin Nutr.  May;97(5) 1134-43. doi: 10.3945/ajcn.112.053371. Epub 2013 Mar 20. 

Web URL: View this and related abstracts via PubMed here.



Docosahexaenoic acid (DHA) is important for brain function, and its status is dependent on dietary intakes. Therefore, individuals who consume diets low in omega-3 (n-3) polyunsaturated fatty acids may cognitively benefit from DHA supplementation. Sex and apolipoprotein E genotype (APOE) affect cognition and may modulate the response to DHA supplementation.


We investigated whether a DHA supplement improves cognitive performance in healthy young adults and whether sex and APOE modulate the response.


Healthy adults (n = 176; age range: 18-45 y; nonsmoking and with a low intake of DHA) completed a 6-mo randomized, placebo-controlled, double-blind intervention in which they consumed 1.16 g DHA/d or a placebo. Cognitive performance was assessed by using a computerized cognitive test battery. For all tests, z scores were calculated and clustered into cognitive domains as follows: episodic and working memory, attention, reaction time (RT) of episodic and working memory, and attention and processing speed. ANCOVA was conducted with sex and APOE as independent variables.


RTs of episodic and working memory improved with DHA compared with placebo (mean difference (95% CI): -0.18 SD (-0.33, -0.03 SD) (P = 0.02) and -0.36 SD (-0.58, -0.14 SD) (P = 0.002), respectively)

Sex × treatment interactions occurred for episodic memory (P = 0.006) and the RT of working memory (P = 0.03). Compared with the placebo, DHA improved episodic memory in women (0.28 SD (0.08, 0.48 SD); P = 0.006) and RTs of working memory in men (-0.60 SD (-0.95, -0.25 SD); P = 0.001)

APOE did not affect cognitive function, but there were some indications of APOE × sex × treatment interactions.


DHA supplementation improved memory and the RT of memory in healthy, young adults whose habitual diets were low in DHA. The response was modulated by sex.

This trial was registered at the New Zealand Clinical Trials Registry ( as ACTRN12610000212055.


This clinical trial involving healthy yound adults found that supplementation with long-chain omega-3 fatty acids led to measurable improvements in memory and reaction time.

Many controlled trials have already shown that omega-3 supplementation can improve aspects of attention and memory in children or adults with developmental or mental health conditions such as ADHD or depression. See:

However, this is the first such trial showing benefits for cognition in the wider general population.