Association Between Omega-3 Supplement Use and Cognitive Function in Korean Older Adults: An 8-Year Longitudinal Cohort Study

Abstract

Objectives: South Korea has a relatively high baseline omega-3 fatty acids (O3FA) status due to dietary patterns. However, evidence on additional benefits of O3FA supplementation remains limited. This study examined the 8-year longitudinal effects of O3FA supplement use on cognitive performance among community-dwelling older adults in South Korea. Design: Prospective longitudinal cohort study. Setting and participants: Data were from the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD). A total of 4,949 adults aged >= 60 years (mean age = 69.55 +/- 6.56; 44.2% men) were included, and 2,053 completed the 8-year follow-up (2010-2012 to 2018-2020). Measurements: O3FA supplement use was assessed through structured questionnaires on regular intake of omega-3 or fish oil supplements. Cognitive performance was assessed using the Korean version of Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet Neuropsychological Assessment Battery (CERAD-K[N]), and total and memory domain scores were analyzed. Longitudinal changes were examined using repeated measures analysis of covariance and linear mixed-effects models (LMMs; unweighted and weighted), adjusting for potential covariates. Results: Over the 8 years, CERAD-K[N] (t = -2.686, p = .007) and memory domain (t = -4.026, p < .001) scores significantly improved among O3FA users. In the weighted LMM, significant time x supplement duration interactions were observed (CERAD-K[N]: beta = 2.398, 95% CI 1.207-3.589, p < .001; memory: beta = 1.050, 95% CI 0.643-1.456, p < .001), indicating greater improvement in long-term users. Conclusion: O3FA supplement use was associated with better maintenance of cognitive function over eight years. These findings suggest a potential role of O3FA supplementation in supporting cognitive health during aging.