N-3 Polyunsaturated Fatty Acids in Elderly with Mild Cognitive Impairment: A Systemic Review and Meta-Analysis

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., Aβ 40, Aβ 42) 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.

Can Nutrition Contribute to a Reduction in Sarcopenia, Frailty, and Comorbidities in a Super-Aged Society?

“…The Mediterranean diet has the potential in preventing heart failure [87,89], the impairment of glycemic control in diabetes mellitus patients [137,138,141], dementia [174,175], and fractures [206,207]. Omega-3 fatty acids, which is abundant in fish oil, may be beneficial in reducing heart failure [88] and dementia [177,178] risk. Additionally, the supplementation of vitamins may contribute to the prevention of various diseases, including vitamin E [132] and folate [133] for glycemic control and insulin resistance in diabetes mellitus patients; vitamin B complex [148] and vitamin E [150] for stroke risk; vitamin B complex, vitamin C, vitamin E and folate [172] for cognitive impairment; vitamin C [214] and vitamin K2 [200] for osteoporosis; and vitamin A [212] and vitamin C [213] for fractures.…”

“…The effect of nutritional interventions containing omega-3 fatty acid, represented by DHA and EPA, on cognitive function, blood amyloid-β-related biomarkers and inflammatory factors was controversial [176][177][178][179]. The effect of supplementing a single vitamin to enhance or maintain cognitive function was also still unclear [180].…”

Can Nutrition Contribute to a Reduction in Sarcopenia, Frailty, and Comorbidities in a Super-Aged Society?

“…The Mediterranean diet has the potential in preventing heart failure [87,89], the impairment of glycemic control in diabetes mellitus patients [138,139,142], dementia [175,176], and fractures [209,210]. Omega-3 fatty acids, which is abundant in fish oil, may be beneficial at reducing heart failure [88] and dementia [178,179] risk. Additionally, the supplementation of vitamins may contribute to the prevention of various diseases, including vitamin E [133] and folate [134] for glycemic control and insulin resistance in diabetes mellitus patients, vitamin B complex [149] and vitamin E [151] for stroke risk, vitamin B complex, vitamin C, vitamin E and folate [173] for cognitive impairment, vitamin C [217] and vitamin K2 [203] for osteoporosis, and vitamin A [215] and vitamin C [216] for fractures.…”

“…The effect of nutritional interventions containing omega-3 fatty acid, represented by DHA and EPA, on cognitive function, blood amyloid-β-related biomarkers and inflammatory factors was controversial [177][178][179][180]. The effect of supplementing a single vitamin to enhance or maintain cognitive function was also still unclear [181].…”

The role of nutrition in the prevention of cognitive decline

“…Some meta-analyses of interventional studies have reported significant benefits for individuals with Alzheimer's disease [17] and MCI [18,19 ▪▪ ] (Table 1). However, there is no supporting evidence that omega-3 LC-PUFA supplementation provides cognitive benefits for either older or younger nondemented individuals [14 ▪▪ ,20,21].…”