Fish consumption and cognitive function in aging: a systematic review of observational studies

Area of Science:

• Neuroscience
• Nutritional Epidemiology
• Gerontology

Background:

• Higher fish intake is linked to slower cognitive decline and reduced dementia risk.
• Observational studies provide evidence for this association, but findings vary.

Purpose of the Study:

• To systematically review observational studies on fish consumption and cognitive function in older adults.
• To identify cognitive domains most consistently associated with fish intake.

Main Methods:

• Systematic review of 25 observational studies (8 cross-sectional, 17 prospective).
• Analysis of studies assessing various cognitive domains including global cognition, memory, executive function, attention, and processing speed.
• Inclusion of studies with diverse participant demographics and assessment tools.

Main Results:

• Regular fish intake (≥1-2 servings/week) was linked to preserved cognitive performance.
• Processing speed, executive functioning, semantic memory, and global cognitive ability showed the most consistent positive associations.
• Associations with verbal memory were less uniform and often attenuated by adjustments.
• Null findings were observed for reaction time and verbal-numerical reasoning in some adjusted models.

Conclusions:

• Evidence suggests regular fish intake supports cognitive health in older adults.
• Specific cognitive domains like processing speed and executive function appear most responsive.
• Further research is needed to clarify inconsistent findings and optimal intake levels.