Summary:
Dementia and Alzheimer’s disease represent a growing public health concern worldwide, prompting interest in lifestyle factors that may help reduce risk. Diet has increasingly been recognised as an important influence on brain health. Nutrients such as healthy fats, antioxidant compounds, and molecules found in food may support neuronal function and reduce inflammation within the nervous system. Dietary patterns that include regular fish intake, such as Mediterranean-style or Nordic diets, have been associated with better cognitive outcomes. Fish has been of particular interest because of its omega-3 fatty acids and other compounds that may have anti-inflammatory and neuroprotective effects. This study is a systematic review and meta-analysis of observational studies that investigated the relationship between fish consumption and cognitive health outcomes, including cognitive decline, dementia, and Alzheimer’s disease. The analysis included 35 studies and found that higher fish consumption was associated with a lower likelihood of cognitive impairment or cognitive decline. Similar associations were observed for dementia and Alzheimer’s disease, although the strength of evidence varied across outcomes. Further analyses suggested that increasing fish intake was linked with progressively lower risk of cognitive problems, with benefits observed at higher consumption levels. Overall, this study indicates that higher fish intake may be associated with reduced risk of cognitive decline, with evidence suggesting a dose-response pattern.
Abstract:
Background: Cognitive impairment is projected to affect a preponderant proportion of the aging population. Lifelong dietary habits have been hypothesized to play a role in preventing cognitive decline. Among the most studied dietary components, fish consumptionhas been extensively studied for its potential effects on the human brain. Aims: To perform a meta-analysis of observational studies exploring the association between fish intake and cognitive impairment/decline and all types of dementia. Methods: A systematic search of electronic databases was performed to identify observational studies providing quantitative data on fish consumption and outcomes of interest. Random effects models for meta-analyses using only extreme exposure categories, subgroup analyses, and dose-response analyses were performed to estimate cumulative risk ratios (RRs) and 95% confidence intervals (CIs). Results: The meta-analysis comprised 35 studies. Individuals reporting the highest vs. the lowest fish consumption were associated with a lower likelihood of cognitive impairment/decline (RR = 0.82, 95% CI: 0.75, 0.90, I2 = 61.1%), dementia (RR = 0.82, 95% CI: 0.73, 0.93, I2 = 38.7%), and Alzheimer’s disease (RR = 0.80, 95% CI: 0.67, 0.96, I2 = 20.3%). The dose-response relation revealed a significantly decreased risk of cognitive impairment/decline and all cognitive outcomes across higher levels of fish intake up to 30% for 150 g/d (RR = 0.70, 95% CI: 0.52, 0.95). The results of this relation based on APOE ε4 allele status was mixed based on the outcome investigated. Conclusions: Current findings suggest fish consumption is associated with a lower risk of cognitive impairment/decline in a dose-response manner, while for dementia and Alzheimer’s disease there is a need for further studies to improve the strength of evidence.
Article Publication Date: 20/08/2024
DOI: 10.1007/s40520-024-02823-6
