logologo

Popular Boards

1 Mentions
Lei Yang, Fengxue Zhao, Yadi Sun | Journal of Alzheimer s Disease | (2023)
Primary Link Archive Pubmed DOI Openalex Full text (OA)

Key Takeaways

Plain English Takeaway

Taking certain fish oil supplements may help older adults with mild memory problems think more clearly, but it probably doesn't help with mood or specific memory skills.

Study Aim

The main goal of this paper is to find out if taking n-3 polyunsaturated fatty acids (n-3PUFAs), specifically docosahexaenoic acid (DHA) and/or eicosapentaenoic acid (EPA), can help older adults with mild cognitive impairment (MCI) improve their thinking abilities, mood, and certain blood markers linked to dementia. Simply put: The study wants to see if fish oil supplements can help older people with early memory problems think better.

Study Design

The authors conducted a systematic review and meta-analysis, which means they searched eight large databases for all randomized controlled trials (RCTs) up to January 2022 that tested DHA and/or EPA supplements in people aged 60 or older with mild cognitive impairment (MCI). They included 12 studies with a total of 1,124 participants. The researchers compared the effects of these supplements to a placebo on overall thinking skills, specific mental abilities, mood, and blood markers. They used statistical methods to check for differences, possible biases, and the reliability of their results. Simply put: The researchers looked at many studies where older adults with memory problems took fish oil pills or a fake pill, and then checked if their thinking improved.

Findings

The review shows that taking DHA and/or EPA supplements led to a small but significant improvement in overall thinking ability in older adults with mild cognitive impairment, compared to those who took a placebo. However, the supplements did not make a clear difference in specific skills like memory, language, or planning, nor did they help with depression. Some studies suggest these supplements might lower certain blood markers linked to dementia and inflammation, but there were too few studies to be sure. The authors recommend more research to understand how these supplements work and who might benefit most. Simply put: Fish oil supplements may help with general thinking in older adults with mild memory loss, but they don't seem to help with mood or specific memory skills.

Abstract

Background: Mild cognitive impairment (MCI) is the prodromal stage of dementia. In this stage, reasonable intervention measures can help to delay the decline of cognitive function. Supplementation of n-3 polyunsaturated fatty acids (n-3PUFAs) may be beneficial to delay the decline of cognitive function in the elderly. Objective: To investigate the effectiveness of docosapentaenoic acid (DHA) or/and eicosapentaenoic acid (EPA) supplements in the elderly with MCI. Methods: Eight electronic databases, PubMed, Cochrane Library, Embase, VIP, SinoMed, Web of Science, CNKI, and WANFANG DATA, were searched for related articles from inception until January 2022. Subgroup analyses and sensitivity analyses were performed to detect confounding variables. Standardized mean differences (SMD) with 95% confidence intervals (CI) were determined. Heterogeneity was evaluated by I2 statistics. Publication bias was detected using funnel plots. Stata12.0 was used for Begg's and Egger's test to quantify whether publication bias. Linear relationship between global cognition and covariates was examined in meta-regression analysis. Results: Twelve studies (n = 1,124) were included. The methodological quality of research is mostly medium. Compared with placebo, n-3PUFAs supplements have benefits on global cognition [SMD = 0.51, 95% CI(0.12, 0.91), p = 0.01]. No significant differences were observed between intervention group and placebo on language fluency, executive functions, and depression. Conclusion: Our findings indicated DHA and/or EPA supplements have benefits on global cognition, and it may also reduce the level of blood amyloid-β (Aβ)-related biomarkers (e.g., Aβ40, Aβ42) and inflammatory factors (e.g., 1L-6, 1L-10). Since there are only two relative articles, more research is needed in the future to clarify the relationship.

Referenced In

Lee Johnson
a month ago
Neurodegenerative Diseases and Brain Aging

N-3 Fatty Acids and Cognitive Decline: New Evidence and Old Questions

A new study published last week in the American Journal of Clinical Nutrition purported to find benefits of a peptide and fatty-acid supplement on cognitive function in older adults, stirring up a long-running debate.

Does eating or supplementing with n-3 polyunsaturated fatty acids (PUFAs) help to slow cognitive decline? Could they help prevent or treat conditions like Alzheimer’s?

New Study Suggests Fish Hydrolysate Improves Episodic and Working Memory

The study randomized 53 healthy older adults to receive either fish hydrolysate or a placebo, and tracked their cognitive performance for three months.

Fish “hydrolysate” is a supplement containing low molecular weight peptides and n-3 PUFAs. Two of the study’s authors worked for a company manufacturing such products.

They found:

  • People taking the supplement performed better on a test of visuospatial learning and episodic memory.  

  • The supplementation group performed better on some measures of working memory, with no differences on others.

The authors mention that larger-scale trials often find no impact of PUFAs on global cognition or in specific areas, but that results are inconsistent. However, with its small sample size, this study doesn’t clear much up.

Do n-3 PUFAs Have Cognitive Benefits?

There are other suggestions that PUFAs may have benefits. In fact, two systematic reviews and meta-analyses found a benefit for mild cognitive impairment.

One 2024 review included 12 studies with 1,124 participants in total. They found evidence of a benefit relative to placebo on global cognition, but noted no differences in language fluency or executive functions. The authors also pointed out that more evidence is needed.

Another review from 2019 looked at 7 randomized controlled trials with 434 participants in total, and found improvements in cognition among elderly adults with mild cognitive impairment. In this (and the previous) review, the authors noted that results varied substantially between studies.

A More Complicated Picture

Evidence for specific conditions like Alzheimer’s is less convincing. For example, one longitudinal study looking at 819 people with Alzheimer’s disease found that omega-3 PUFA supplementation actually accelerated cognitive decline.

The authors of this study point to another review which noted improvements at lower dosages but issues at higher dosages.

Overall, while n-3 fatty acids may help mild cognitive impairments at lower doses, the evidence is shakier for more serious issues and higher dosages.

Read Full Post
0