Epigenetics and Dietary Phytochemicals: Modulating Gene Expression for Disease Prevention

Abstract

Epigenetics refers to changes in chromatin organisation and gene expression that occur without alteration of the DNA sequence. This review discusses how dietary phytochemicals and nutritional states may influence epigenetic mechanisms relevant to disease prevention. The manuscript focuses on DNA methylation, histone acetylation, histone methylation, histone biotinylation and microRNA-mediated regulation, and describes how these processes can be affected by nutrients, methyl donors and bioactive plant compounds. Evidence discussed in the review indicates that nutrition during maternal, paternal, periconceptional and postnatal periods can influence methylation patterns, gene expression and metabolic outcomes in offspring. The review also examines selected phytochemicals, including genistein, curcumin, sulforaphane, epigallocatechin-3-gallate and diallyl sulfide, with emphasis on their reported interactions with DNA methyltransferases, histone deacetylases, histone methyltransferases and microRNAs in experimental models. The selected examples show how these compounds may influence tumour-suppressor genes, oncogenic pathways, inflammatory responses and metabolic regulation through epigenetic mechanisms. The role of nutritional imbalance is considered alongside evidence for dietary patterns that may contain multiple bioactive components. Additional sections consider the epigenetic implications of overnutrition, high-fat diets, the Southern European Atlantic Diet and historical exposures to famine, starvation and obesity-related risk in South Asian populations. Overall, the evidence presented suggests that diet may contribute to gene-expression regulation through reversible epigenetic mechanisms and may therefore represent a modifiable factor in disease prevention. However, the review also recognises that the specificity, safety and long-term consequences of dietary epigenetic modulation require further clarification, particularly because bioactive compounds may act through multiple molecular targets and may vary in effect according to dose, exposure period and biological context.