TITLE:
Effects of Food Supplementation with Fish Oil on Cognitive Function in Middle-Aged and Older Adults—A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study
AUTHORS:
Natsuki Matsuoka, Chihiro Fukuzaki, Takumi Morikawa, Shinichiro Takashima, Tomoyasu Kamiya, Kinya Takagaki, Go Maekawa, Yukino Miura, Akari Matsumoto, Kei Kageyama, Moe Koshikawa, Hirona Fukushima, Maoko Tsuchiya, Chihiro Matsushima, Daisuke Tsuge
KEYWORDS:
Fish Oil, Docosahexaenoic Acids, Cognitive Function
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.17 No.3,
March
11,
2026
ABSTRACT: Background: To delay the onset of dementia with age, healthy adults must take preventive measures before cognitive decline occurs. Cognitive decline leads to a decrease in the quality of life (QOL). Fish oil also improves cognitive functions. Therefore, we examined the effects of fish oil intake on the cognitive function and QOL of middle-aged and older adults. Methods: A randomized, double-blind, placebo-controlled, parallel-group study was conducted to evaluate the effects of fish oil on cognitive function and QOL in middle-aged and older participants. One hundred and ten participants were enrolled and randomly divided into active and placebo food groups. Participants consumed either food containing fish oil or food without fish oil for 12 weeks. As the main outcome, cognitive function was assessed before and after ingestion using the Wechsler Memory Scale-Revised and the Stroop test. The secondary outcome, QOL, was also examined using SF-36. Results: The active food group showed statistical significance in the “Logical Memory I” and “Stroop interference rate” compared to the placebo food group (P Conclusions: Overall, fish oil improved cognitive function in middle-aged and older adults.