An exploration of the role of a fish-oriented diet in cognitive decline: a systematic review of the literature

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.

Fish Intake May Affect Brain Structure and Improve Cognitive Ability in Healthy People

“…The findings in our study suggest that people with a good whole brain health condition, measured by FA-BHQ, tend to have lower risks of MCI. Although some previous studies found a direct effect of fish intake on prevention of MCI, the findings were limited and inconsistent (Zeng et al, 2017). Notably, the present study indicates that broader approaches can be used to prevent MCI by focusing on not only dietary factors but also FA-BHQ scores.…”

“…However, some studies have shown that fish consumption does not have a protective effect on MCI. A meta-analysis by Zeng et al (2017) found no statistically significant association between fish intake and the risk of MCI. The inconsistency in the association between fish intake and MCI may be due to indirectness.…”

Adherence to a Mediterranean diet and cognitive function in the Age‐Related Eye Disease Studies 1 & 2

“…The current study adds strength to this potentially important association. Other meta‐analyses have observed that higher fish intake is associated with decreased risk of dementia 58,60 and/or AD 58–61 …”

“…Regarding fish intake, again, multiple systematic reviews have been conducted 17,58–62 . In a recent meta‐analysis of five cohort studies, higher fish intake was associated with slower decline in global cognition, particularly episodic memory 17 .…”

A contemporary view of the possibilities of preventing dementia

“…Регулярное потребление обоих этих жиров может уменьшать эндотелиаль-ную дисфункцию, уровень триглицеридов и оказывать противовоспалительное действие. Систематический обзор проспективных исследований, включавших 28 754 субъекта, при сравнении максимального и наименьшего уровня потребления рыбы выявил суммарный относительный риск для БА, равный 0,80 (95% ДИ = 0,65-0,97), т. е. люди с более высоким потреблением рыбы имели 20%-ное (95% ДИ = 3-35%) снижение риска БА [35].…”