Cognitive aging is a complex, multifactorial process influenced by genetic, metabolic, and environmental factors. Among modifiable risk factors, nutrition has emerged as a promising target to preserve cognitive function. This review provides a comprehensive overview of the impact of dietary interventions-including specific nutrients and dietary patterns-on cognitive domains (memory, executive function, global cognition) and mental health. Recent findings: multinutrient supplementation, particularly combinations of B vitamins and omega-3 fatty acids, appears beneficial for episodic memory, especially in individuals with metabolic risk or early cognitive impairment. Antioxidant-rich diets and the MIND diet are consistently associated with better memory and global cognitive outcomes in observational studies. Effects on executive function and mental health remain heterogeneous, although subgroups such as those with mild cognitive impairment or depression may derive benefit. Evidence from interventional studies remains limited by methodological variability. In conclusion, dietary interventions offer a safe and promising approach to support cognitive health in aging. Future research should focus on developing personalized, multidomain prevention models tailored to individual risk profiles.