Twelve weeks of supplementation was also associated with a significant reduction in a range of inflammatory marker compounds: A beneficial result considering that inflammation is reported to be a major factor in many age-associated sources of death and disability, note the Ohio State scientists.
“The reduction in anxiety symptoms associated with [omega]-3 supplementation provides the first evidence that [omega]-3 may have potential [anti-anxiety] benefits for individuals without an anxiety disorder diagnosis,” wrote the authors in Brain, Behavior, and Immunity .
The study adds to the ever growing body of science supporting the potential health benefits of omega-3. The majority of the science has focused on the cardiovascular benefits of the oils, but an increasing number of studies are reporting the potential cognitive effects related to mood and behavior.
The health benefits of omega-3 fatty acids have been well communicated to consumers and this has led to a buoyant market for omega-3 products, recently valued at almost $8 billion (€5.57 billion) by Packaged Facts.
According to the report, the market grew 17% from 2009 and such growth is predicted to continue, said the market researcher.
The US dominates with sales of $4bn (€2.78bn) in foods and drinks compared to $1.3bn (€900m) for dietary supplements, with much of the food and beverage figure accounted for by omega-3 fortified infant foods and formulas.
“Observational studies have linked lower omega-3 polyunsaturated fatty acids (PUFAs) and higher omega-6 PUFAs with inflammation and depression, but randomized controlled trial (RCT) data have been mixed,” explained the researchers.
In order to provide RCT data, the Ohio State researchers recruited 68 medical students to participate in their parallel group, placebo-controlled, double-blind trial. The med students were given either placebo capsules or omega-3 capsules containing 2085 mg of EPA (eicosapentaenoic acid) and 348 mg DHA (docosahexanoic acid). The supplements and placebo were provided by OmegaBrite and the study was supported financially by a grant from the National Institutes of Health.
Results showed a 14% reduction in levels of the production of pro-inflammatory interleukin 6 (IL-6), as well as a 20% reduction in anxiety symptoms in the omega-3 group, compared to the placebo group.
“The reduction in anxiety symptoms associated with omega-3 supplementation provides the first evidence that omega-3s may have potential [anti-anxiety] benefits for individuals without an anxiety disorder diagnosis,” wrote the researchers.
“Proinflammatory cytokines promote secretion of corticotropin-releasing hormone (CRH), a primary gateway to hormonal stress responses; CRH also stimulates the amygdala, a key brain region for fear and anxiety. Accordingly, alterations in inflammation could also influence anxiety.”
However, the researchers noted no effect on symptoms of depression, which they add agrees with results from a meta-analysis (American Journal of Clinical Nutrition, 2010, Vol. 91, pp. 757-770).
Source: Brain, Behavior, and Immunity
Published online ahead of print, doi:10.1016/j.bbi.2011.07.229
“Omega-3 supplementation lowers inflammation and anxiety in medical students: A randomized controlled trial”
Authors: J.K. Kiecolt-Glaser, M.A. Belury, R. Andridge, W.B. Malarkey, R. Glaser