Various dietary patterns (DPs) may benefit or harm cognitive status through their components. Publications assessing the impact of DPs on cognitive scores using neuropsychological tests have often led to less promising results. Recently, numerous meta-analyses and systematic reviews have utilized neuroimaging to identify more subtle brain-associated alterations related to cognition. Combining neuroimaging methods with neuropsychological assessments could clarify these findings. This umbrella review was conducted to systematically explore evidence on the impact of DPs on neuroimaging biomarkers in older adults with cognitive disorders. Scientific databases, including Scopus, PubMed, and Web of Science, were comprehensively searched from the earliest available data until May 11, 2024. Out of 89 papers, 15 meta-analyses and systematic reviews were included in our umbrella review. These selected papers addressed 27 DPs and their impact on neuroimaging biomarkers. Most selected papers were of moderate quality. Studies revealed that greater adherence to the Mediterranean diet (MedDiet) correlated with increased cortical thickness, improved glucose metabolism in the brain, and reduced amyloid-beta and tau deposition, as evidenced by magnetic resonance imaging and other neuroimaging techniques. Higher adherence to healthy DPs, such as the MedDiet, reduced the risk of Alzheimer's disease and mild cognitive impairment. In contrast, Western and high glycemic diets were associated with increased cognitive decline.

Background: Multiple sclerosis (MS) is a multifaceted neurodegenerative disorder influenced by genetics and lifestyle. This systematic literature review investigates the role of six obesity‐associated genes, including fat mass and obesity‐associated (FTO), FAS apoptosis inhibitory molecule 2 (FAIM2), Niemann–Pick disease type C1‐like 1 (NPC1), glucosamine‐6‐phosphate deaminase 2 (GNPDA2), melanocortin‐4 receptor (MC4R), and brain‐derived neurotrophic factor (BDNF) in the context of MS.Methods: A literature search was executed using Embase, Scopus, Cochrane, Web of Science, and PubMed databases from inception to July 2024. The related keywords employed during the search process are “fas apoptotic inhibitory molecule 2,” “Niemann–Pick disease type C1,” “fat mass and obesity‐associated,” “melanocortin‐4 receptor,” “brain‐derived neurotrophic factor,” “glucosamine‐6‐phosphate deaminase 2,” and “multiple sclerosis.”Results: Out of 2108 papers, 27 were entered into the present systematic literature review. The FTO gene may affect MS susceptibility through metabolic and inflammatory pathways. FAIM2 and NPC1 genes may contribute to MS pathogenesis, though their precise roles are still being elucidated. The GNPDA2 gene may have some connections with MS but requires further clarification. MC4R has demonstrated significant neuroprotective and anti‐inflammatory effects, suggesting its potential impact on MS progression. BDNF plays a complex role in neuronal survival and repair and may influence the risk of MS.Conclusion: Our findings demonstrated that obesity‐related genes may have a significant impact on MS risk and disease course, revealing novel insights into the genetic underpinnings of MS.