[Nut consumption and cognitive function: a systematic review]

Antioxidant-rich diet patterns could contribute to the prevention and treatment of early stages of dementia. Nuts have an appreciable antioxidant load and there is evidence of their positive effects on several chronic diseases incidence and death rates. Moreover, they are rich in polyunsaturated fatty acids, which might also play a positive role in neurogenesis. The aim of this systematic review was to summarize the evidence from studies related to the effects of nut consumption on cognitive function among adults. We conducted a systematic search of articles published in PubMed, Scopus and Web of Science. A total of 19 articles met the inclusion criteria (seven cross-sectional, four prospective cohorts and eight experimental); these were independently extracted and reviewed by two reviewers. The evidence from the cross-sectional and cohort studies was uncertain, due to the disparity of results and risk of bias. However, in most experimental studies a protective effect of nut consumption on some dimension of cognitive function was observed and the methodological quality of these studies was acceptable. In addition, the effects appear to be independent of nut type, amount of intake, age and baseline status of subjects. In summary, these results suggest that the inclusion of daily nut consumption in the healthy diet pattern of adults could have positive effects on their cognitive function. Nevertheless, more well-designed longitudinal and experimental studies are needed to provide strength to this suggestive evidence.