Background: The global increase in life expectancy has led to a higher prevalence of age-related cognitive decline, highlighting the need for effective non-pharmacological interventions. This systematic review aimed to evaluate the potential effects of olive oil, particularly its bioactive compounds and fatty acid profile, on cognitive function in adults Methods: A comprehensive literature search was conducted in PubMed, Scopus, and EBSCO in accordance with PRISMA 2020 guidelines, including peer-reviewed studies published in English between 2015 and 2025. A total of six studies met the inclusion criteria and were included in the final qualitative synthesis, comprising five randomized controlled trials and one prospective cohort study. Risk of bias was assessed using the Cochrane Risk of Bias tool (RoB 2) and the Newcastle–Ottawa Scale. Results: The findings suggest that consumption of extra virgin olive oil (EVOO), particularly high-phenolic varieties, may be associated with improvements in cognitive domains such as memory, attention, executive function, and global cognition. However, the evidence is derived from a limited number of heterogeneous studies with relatively small sample sizes. Most of the available data relate to high-phenolic EVOO and olive-derived bioactive compounds, while studies directly examining the role of fatty acid composition remain limited. Proposed mechanisms include reduced blood–brain barrier permeability, enhanced brain functional connectivity, and the neuroprotective effects of compounds such as hydroxytyrosol and oleuropein. Conclusions: While the findings suggest potential cognitive benefits of EVOO, the current evidence remains preliminary and insufficient to establish causality. Therefore, results should be interpreted with caution. Further large-scale, well-designed randomized controlled trials are required to confirm these associations and clarify the specific contributions of fatty acids and bioactive compounds.

The Mediterranean diet is recognised as one of the healthiest dietary patterns worldwide; however, adherence has declined even within Mediterranean populations. This study investigated Mediterranean diet adherence and examined its associations with preferences for traditional dairy products and olive-related products among adults participating in a study in Cyprus. A cross-sectional online survey was conducted among 273 adults using a structured questionnaire that included sociodemographic and lifestyle characteristics, the 14-item Mediterranean Diet Adherence Screener (MEDAS), and questions assessing preferences for and consumption of dairy products, olive oil, olive-derived products, and foods prepared with olive oil. Descriptive statistics, principal component analysis, and multiple linear regression were performed. The mean MEDAS score was 8.1 ± 2.6; using study-specific descriptive categories, 40.0% of participants had scores classified as good to excellent adherence. Olive oil was the most preferred and most frequently consumed olive-related product, with 75.1% of participants reporting that they “liked very much” olive oil and 49.8% consuming it daily. In the primary multivariable analysis, older age, greater traditional dairy preference, greater olive-related preference, and more frequent olive-related consumption were associated with higher MEDAS scores, whereas sex, body mass index, smoking status, and physical activity were not significantly associated with MEDAS score. However, in a sensitivity analysis excluding the two olive-oil-related MEDAS components, the olive-related preference and consumption associations were no longer statistically significant. Overall, traditional food preferences were associated with Mediterranean diet adherence within this convenience sample; however, the olive-related findings should be interpreted cautiously because of potential construct and measurement overlap. Given the cross-sectional design and demographic characteristics of the sample, these findings do not establish temporality or causality and should not be considered representative of the general adult population of Cyprus.