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The health benefits of omega-3 fatty acid (FA) supplementation on inflammatory gene expression (IGE) and multiple sclerosis (MS) are becoming more evident. However, an overview of the results from randomized controlled trials is lacking. This study aimed to conduct a meta-analysis to evaluate the effect of omega-3 fatty acid intake on MS (based on the criteria of the Expanded Disability Status Scale (EDSS)) and inflammatory gene expression (IGE). A search was conducted of PubMed, EMBASE, and Web of Science for cohort studies published from the inception of the database up to May 2022 that assessed the associations of omega-3 polyunsaturated fatty acids (n-3 PUFAs), docosahexaenoic acid (DHA), α-linolenic acid (ALA), and eicosapentaenoic acid (EPA) with EDSS and inflammatory gene expression (peroxisome proliferator-activated receptor gamma (PPAR-γ), tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and interleukin-8 (IL-8)) outcomes. For the highest vs. lowest comparison, the relative risk (RR) estimates with a 95% confidence interval (CI) were pooled using the random-effect model. In total, 13 cohort studies with 1353 participants were included in the meta-analysis during periods of 3 to 144 weeks. A significant inverse relationship was found between DHA and EDSS scores (RR: 1.05; 95% CI: 0.62, 1.48; p < 0.00001). Our results also showed that omega-3 FAs significantly upregulated the gene expression of PPAR-γ (RR: 0.95; 95% CI: 0.52, 1.38; p < 0.03) and downregulated the expression of TNF-α (RR: −0.15; 95% CI: −0.99, 0.70; p < 0.00001) and IL-1 (RR: −0.60; 95% CI: −1.02, −0.18; p < 0.003). There was no clear evidence of publication bias with Egger’s tests for inflammatory gene expression (p = 0.266). Moreover, n-3 PUFAs and EPA were not significantly associated with EDSS scores (p > 0.05). In this meta-analysis of cohort studies, blood omega-3 FA concentrations were inversely related to inflammatory gene expression (IGE) and EDSS score, which indicates that they may hold great potential markers for the diagnosis, prognosis, and management of MS. However, further clinical trials are required to confirm the potential effects of the omega-3 FAs on MS disease management.

Cognitive decline induced by oxidative brain damage is the critical pathological hallmark of Alzheimer's disease. Studies have shown that individual administration of Boswellia serrata Roxb (BS), Zingiber officinale Roscoe (ZO) and Ginkgo biloba L. (GB) extracts improved memory and learning through a different mechanism of actions. This study aims to compare the individual effects of each extract with their co-administration on memory impairment induced by scopolamine in mice. Memory dysfunction was induced by a single dose of scopolamine (1 mg/kg, i.p) and extracts were administered intraperitoneally in different doses for one week. Memory performance of the mice was evaluated using the object recognition task (ORT) and passive avoidance test (PAT). The outcomes from ORT demonstrated that, ZO and GB extracts at 200 mg/kg and BS extract just in combination group significantly enhanced (by 95%) the memory loss induced by scopolamine (P < 0.05). On the other hand, PAT results revealed that BS extract at 60 and 90 mg/kg, ZO and GB extracts at 200 mg/kg and their combinations noticeably improved the latency time (by 80%). Although in PAT, co-administration of extracts was more effective than either alone doses in augmenting of the memory function, ORT results showed no considerable differences.