Abstract
Background: Mood disturbances, often accompanied by cognitive deficits, represent a major public health challenge. Diet is increasingly recognized as a modifiable factor in mental health, with specific nutrients such as omega-3 polyunsaturated fatty acids (PUFAs) showing therapeutic potential. This study investigated whether dietary omega-3 intake moderates variations in cognitive performance associated with psychological symptoms in non-clinical samples. Method: A total of 313 healthy adults completed a food frequency questionnaire (FFQ) to assess dietary intake. Psychological symptoms were measured using the depression screening questionnaire (PHQ-9) and the stress assessment instrument (PSS-10), while cognitive performance, including short-term and episodic memory, was evaluated using Sternberg and Old/New recognition tests. A subgroup of 52 older adults completed a detailed in-person FFQ to enable the precise quantification of EPA, DHA, and alpha-linolenic acid (ALA) intake. Results: Diets rich in omega 3, particularly nuts, seeds, fish and seafood, were associated with lower depression and stress scores. EPA and DHA, but not ALA, were specifically linked to those mood benefits. However, dietary omega-3 intake was not significantly associated with cognitive performance and did not moderate the relationship between mood and memory. Self-reported omega-3 supplementation was linked to fewer depressive symptoms and better episodic memory. Conclusions: While dietary omega-3 is associated with improved well-being, its role in cognition in healthy adults is not well-established and warrants further investigation.