Abstract
Epidemiological studies have presented inconsistent evidence of the correlation between a fish-oriented dietary intake (FDI) and the risk of cognitive decline. To address these controversies, we performed this systematic review of prospective studies published in December 2016 and earlier using PubMed, Embase, and Web of Science. Two independent researchers conducted the eligibility assessment and data extraction; all discrepancies were solved by discussion with a third researcher. The pooled relative risks (RRs) focused on the incidence of events were estimated with 95% confidence intervals (CIs). Overall, nine studies containing 28,754 subjects were analyzed. When the highest and lowest categories of fish consumption were compared, the summary RR for dementia of Alzheimer type (DAT) was 0.80 (95%CI = 0.65–0.97); i.e., people with a higher intake of fish had a 20% (95%CI = 3–35%) decreased risk of DAT. Additionally, the dose-response synthesized data indicated that a 100-g/week increase in fish intake reduced the risk of DAT by an additional 12% (RR = 0.88, 95%CI = 0.79–0.99). Non-significant results were observed for the risk of dementia of all causes (DAC) and mild cognitive impairment (MCI). Limited evidence involving heterogeneity was found within subgroups or across studies. In conclusion, this review confirmed that a higher intake of fish could be correlated with a reduced risk of DAT. Further research, especially prospective studies that specifically quantify FDI, will help find a more accurate assessment of the different levels of dietary intake.
Highlights
As the population ages worldwide, it is expected that the prevalence of cognitive disorders, including dementia of Alzheimer type (DAT), mild cognitive impairment (MCI), and dementia of other causes, might increase in future decades [1,2]
Regarding the role of nutrition in the prevention of cognitive disorders, increased hope has focused on a fish-oriented dietary intake (FDI), since fish is an important source of omega-3 fatty acids (n-3 FAs) [4,5]
The results showed no definite correlation between Eicosapentaenoic acid (EPA) intake and the risk of dementia of all causes (DAC) (RR, 0.97 [95% confidence intervals (CIs), 0.77-1.22])
Summary
As the population ages worldwide, it is expected that the prevalence of cognitive disorders, including dementia of Alzheimer type (DAT), mild cognitive impairment (MCI), and dementia of other causes, might increase in future decades [1,2]. Other studies reported that a diet enriched with DHA could lessen the www.impactjournals.com/oncotarget neurodegenerative pathology and protect from cognitive decline in aged rats [8,9]. Given the uncertain evidence regarding the roles of an FDI and the risk of cognitive decline, we performed this updated systematic review by searching and analyzing published studies. This meta-analysis was limited to prospective cohort studies because casecontrolled studies might contain bias, especially when it comes to recalling previous dietary habits after cognitive disorders have been diagnosed. It was assumed that the heterogeneity among results might be much smaller when similar study designs are considered
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
