Diet has a profound impact on brain health, particularly in middle-aged and older adults, who are at increased risk of cognitive decline and neurodegenerative diseases. Various dietary patterns, including the Mediterranean diet (MedDiet), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets, have been linked to improved cognitive function. While the relative effectiveness of these diets on brain health is generally supported by evidence, variability in study results suggests that further research is needed to fully understand their effects across diverse populations. The objective of this descriptive narrative review is to examine the role of dietary patterns in supporting brain health in aging populations and to propose practical dietary strategies for promoting cognitive well-being. A comprehensive review of the existing literature was conducted on PubMed in October 2024, with no restrictions on language, publication date (1966–2024), or geographic location. A total of 18 articles were included in this review, covering the years 2013–2023. Studies assessing the impact of the MedDiet, DASH, MIND, and Western diets on cognitive function in middle-aged and older adults were prioritized. The research findings were synthesized to identify common and unique recommendations across these dietary patterns. The MedDiet consistently showed beneficial effects on cognitive health, including improved memory, processing speed, and long-term protection against neurodegenerative conditions. The DASH and MIND diets demonstrated potential benefits, particularly for specific cognitive domains, but the results were more mixed and inconclusive. In contrast, adherence to a Western diet was associated with negative cognitive outcomes, including cognitive decline and smaller brain volumes. These findings underscore the importance of adopting healthy dietary patterns as a modifiable lifestyle factor to support cognitive aging and inform future public health strategies and clinical guidelines.