Omega-3 fatty acids and stress-induced changes to mood and cognition in healthy individuals

• Omega-3 fatty acids (n-3 PUFAs) have equivocal effects on depressive mood.
• Whether n-3 PUFAs influence stress-related mood in healthy individuals is unknown.
• Evaluated how n-3 PUFA intake influences mood and cognition in times of stress
• n-3 PUFA intake stabilized feelings of anger and confusion during stress.
• n-3 PUFA intake exerted few effects in stressful and non-stressful situations.

Omega-3 fatty acid (n-3 PUFA) intake is associated with improved mood and cognition, but randomized controlled trials addressing the causal nature of such relationships are less clear, especially in healthy, young adults. Stress is one potential mechanism by which n-3 PUFAs may influence mood. Thus the present aim is to evaluate the influence of n-3 PUFA supplementation on stress-induced changes to mood, cognition, and physiological stress markers in healthy, young adults. Using a double-blind, placebo-controlled design, 72 young adults were randomized to receive 2800 mg/day fish oil (n = 36, 23 females) or olive oil control (n = 36, 22 females) for 35 days. Subjects completed measures of mood and cognition before supplementation, and two times after supplementation: following an acute stressor or non-stressful control task. The stress induction was effective in that the stressor impaired mood, including augmenting feelings of tension, anger, confusion and anxiety, reduced accuracy on a cognitive task measuring attentional control and the ability to regulate emotion, and increased salivary cortisol and pro-inflammatory cytokine interleukin-1β (IL-1β). Rated anger and confusion increased with stress in the olive oil group, but remained stable in the fish oil group. However, fish oil had no further effects on mood, cognitive function, cortisol, or IL-1β. Fish oil exerted few effects in stressful and non-stressful situations, consistent with findings showing little influence of n-3 PUFA supplementation on mood and cognition in young, healthy individuals. Potential target populations who would more likely benefit from increased n-3 PUFA intake are discussed.