Scientific Study

Context: The consumption of nuts has beneficial effects on cardiovascular health, body composition, cognitive functions, the intestinal microbiota, and satiety control, but how nuts and their nutrients impact related gene expression is unclear. Objective: We analyzed the effects of nut consumption on human gene expression as investigated in controlled clinical trials. Data Sources: This systematic review was conducted according to the PRISMA guidelines. The databases used in the search were MEDLINE/PubMed, Embase, and the Cochrane Library. Data Extraction: Randomized and nonrandomized controlled trials conducted to date that evaluated the effect of nut consumption on the mRNA expression of human genes were evaluated according to eligible criteria. Two authors screened and determined the quality of the studies; disagreements were resolved by the third author between May and June 2024. All authors were involved in analyzing the compiled data. Data Analysis: We selected 13 original articles. Most studies evaluated the effects of Brazil nuts, followed by studies using combinations of two or more nuts, with an interventional duration of six weeks to one year. The consumption of hazelnuts and Brazil nuts increased expression in antioxidant-related genes, while beneficial regulation of proinflammatory pathways (tumor necrosis factor - TNF, interleukin-6 - IL-6, and toll-like receptors 2 and 4 - TLR2 and TLR4) was reported after consumption of Brazil nuts. Genes involved in vascular inflammation (eg, ciclooxygenase-2 - COX-2) were downregulated after the consumption of mixed nuts, and the expression of selenoprotein - SELENOP and glutathione peroxidase 1 - GPX1 were regulated according to the presence of single nucleotide polymorphisms after the consumption of Brazil nuts. Finally, pistachio consumption reduced telomere oxidation (telomerase reverse transcriptase - TERT and WD repeat containing antisense to TP53 - WRAP53) and downregulated resistin and IL-6 genes. Conclusion: The consumption of nuts has beneficial effects on human health, modulating gene expression involved in the progression of chronic diseases, with emphasis on the pathways of inflammation, oxidative stress, and cardiovascular health.

https://doi.org/10.1093/nutrit/nuaf023