[Note: Even in healthy young subjects without diagnosed anxiety disorders, this trial demonstrated that higher levels of dietary omega-3 fish oil (2.5 grams a day) supported significant reduction of anxiety symptoms and the pro-inflammatory cytokines that accompany depression, stress, and many age-associated sources of death and disability. Further, the authors have noted that the medical students as a group already tended to eat foods supporting a much healthier omega-3 to omega-6 ratio than the US population overall. The researchers therefore suggest that even greater benefits might be derived from omega-3 supplementation by individuals with less healthful diets and/or anxiety, stress, and other inflammation-related disorders.]
Observational studies have linked lower omega-3 (n-3) polyunsaturated fatty acids (PUFAs) and higher omega-6 (n-6) PUFAs with inflammation and depression, but randomized controlled trial (RCT) data have been mixed.
To determine whether n-3 decreases proinflammatory cytokine production and depressive and anxiety symptoms in healthy young adults, this parallel group, placebo-controlled, double-blind 12-week RCT compared n-3 supplementation with placebo.
The participants, 68 medical students, provided serial blood samples during lower-stress periods as well as on days before an exam. The students received either n-3 (2.5 g/d, 2085 mg eicosapentaenoic acid and 348 mg docosahexanoic acid) [fish oil] or placebo capsules that mirrored the proportions of fatty acids in the typical American diet.
Compared to controls, those students who received n-3 [fish oil] showed:
• A 14% decrease in lipopolysaccharide (LPS) stimulated interleukin 6 (IL-6) production [inflammatory markers]
• And a 20% reduction in anxiety symptoms, without significant change in depressive symptoms.
Individuals differ in absorption and metabolism of n-3 PUFA supplements, as well as in adherence; accordingly, planned secondary analyses that used the plasma omega-3 to omega-6 ratio in place of treatment group showed that decreasing omega-3 to omega-6 ratios led to lower anxiety and reductions in stimulated IL-6 and tumor necrosis factor alpha (TNF-alpha) production, as well as marginal differences in serum TNF-alpha.
These data suggest that n-3 supplementation can reduce inflammation and anxiety even among healthy young adults.
The reduction in anxiety symptoms associated with n-3 supplementation provides the first evidence that n-3 may have potential anxiolytic [anxiety-reducing] benefits for individuals without an anxiety disorder diagnosis.
ClinicalTrials.gov identifier: NCT00519779
Source: Brain, Behavior, and Immunity, online Jul 16, 2011. Kiecolt-Glaser JK, Belury MA, Andridge R, Malarkey WB, Glaser R. Institute for Behavioral Medicine Research, and Departments of Psychiatry, Internal Medicine, Molecular Virology, Immunology, and Medical Genetics, Ohio State University College of Medicine; Department of Human Nutrition, Ohio State University, Columbus, Ohio, USA. [E-mail: Janice.Kiecolt-Glaser@osumc.edu]