The apparent brain-boosting benefits of fish oil are related the combination of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), which calls into question the use of pure EPA supplements in some mental health studies.
For the new study, fish oil supplements were associated with improvements in scores on the Geriatric Depression Scale (GDS) and verbal fluency.
The new study – published in the British Journal of Nutrition – adds to an every growing body of science supporting the potential cognitive benefits of fish oil and the omega-3 fatty acids it contains.
Consumer interest in omega-3 has led to a blossoming market, recently valued at almost $8 billion (€5.57 billion) by Packaged Facts.
The majority of the science focuses on heart health, but an increasing number of studies have reported benefits for mood, behavior, and mental function.
Such is the interest in the area of omega-3 and brain health that the US Army is studying the effects of omega-3 status on suicide rates of troops and service personnel (Journal of Clinical Psychiatry, doi: 10.4088/JCP.11m06879), and how omega-3 supplementation may improve mental health and stress resilience.
Researchers from the University of South Australia and the Queensland University of Technology recruited 50 people over the age of 65 to participate in their six-month double-blind, randomized controlled trial.
Participants received daily supplements of EPA- or DHA-rich fish oil, or the omega-6 linoleic acid (LA, 2.2 grams per day). The EPA-rich supplement provided 1.67 grams of EPA and 0.16 grams of DHA, while the DHA-rich supplement provided 1.55 grams of DHA and 0.40 grams of EPA.
Led by Dr Natalie Sinn from the University of South Australia, the researchers reported that, compared with the group receiving the LA supplements, the EPA and DHA groups both showed improved GDS scores following 6-months of supplementation, and these improvements were more pronounced in the DHA group.
“These results indicate that DHA-rich and EPA-rich fish oils may be effective for depressive symptoms and health parameters, exerting variable effects on cognitive and physical outcomes,” wrote the researchers.
“The present findings suggest that pure EPA supplements employed in some mental health studies may not be the optimal choice.
“Future research should further investigate this in larger, clinically depressed samples of people with MCI and conduct longitudinal follow-up to assess whether the risk of progression to dementia is reduced in these populations,” they concluded.
Source: British Journal of Nutrition
Published online ahead of print, FirstView Article, DOI:10.1017/S0007114511004788
“Effects of n-3 fatty acids, EPA v. DHA, on depressive symptoms, quality of life, memory and executive function in older adults with mild cognitive impairment: a 6-month randomised controlled trial”
Authors: N. Sinn, C.M. Milte, S.J. Street, J.D. Buckley, A.M. Coates, J. Petkov, P.R.C. Howe