ABSTRACT. It is estimated that by 2030 there will be 82 million people in the world with dementia. Objective: To evaluate the effect of dietary interventions on the cognitive performance of individuals with Alzheimer’s disease (AD). Methods: A systematic review of randomized controlled trials (RCT) was conducted in the Scopus, PubMed, and Cochrane databases. Thirty-two RCT were included. Results: Omega-3 fatty acid showed positive effects at different doses. Fortasyn Connect seemed to be effective in the early stages of the disease. Probiotic, Ginseng, Inositol and specialized nutritional formulas seemed to have a positive effect on cognition. Most of the primary studies presented poor methodological quality, included patients with mild AD, small samples, and did not obtain significative results for all the cognitive outcomes. Conclusions: The effect of most dietary interventions on cognition in AD patients remains inconclusive, however, several nutrients, isolated or not, show potential to improve cognitive function in AD, especially in its early stages.