The Role of Dietary Factors in Prevention of Age-Related Cognitive Impairment: A Descriptive Literature Review

Introduction: No effective pharmaceutical treatment for age-related cognitive impairment and dementia is available nowadays, so prevention plays a key role. Objective: To summarize published data on the influence of various dietary factors on cognitive functions and associated pathological processes. Materials and Methods: We searched for publications on the topic issued over the previous 36 years in the MEDLINE and Google Scholar electronic databases, selected 72 studies containing an empirical assessment of the role of nutritional factors in preventing age-related cognitive disorders, and performed their descriptive analysis. Results: Excessive intake of added and refined sugars is associated with impaired cognitive performance; increased intake of omega-3 polyunsaturated fatty acids is associated with a lower risk of age-related cognitive decline while saturated fats pose a higher risk. High protein intake has been shown to correlate with better cognitive outcomes. Tyrosine and tryptophan have a positive effect on memory and reaction time so their high intake mitigates the risks of cognitive decline and Alzheimer’s disease by reducing oxidative stress. Vitamin D deficiency is linked to an increased risk of cognitive impairments. Adequate polyphenol intake demonstrates neuroprotective, neuroplastic, and anti-inflammatory effects. Dietary adherence determines cognitive outcomes: commitment to the Mediterranean diet is associated with a lower risk of mild cognitive impairment and Alzheimer’s disease. The Mediterranean-DASH Diet Intervention for Neurodegenerative Delay was developed by scientists to reduce the risk of cognitive impairments, as well as to slow brain aging and prevent Alzheimer’s disease. The ketogenic/low-carbohydrate diet improves memory. The Western-style diet is associated with accelerated cognitive decline and an increased risk of dementia; it enhances inflammation and vascular-metabolic risk factors. Conclusions: Most studies suggest potential benefits of consuming certain micronutrients for cognitive health and lower risks of age-related cognitive disorders in different groups of population. Changes in modifiable lifestyle factors and, above all, nutrition are key strategies for maintaining brain health in aging.