Nutrition, epigenetics and ageing

Dietary practices can determine health outcome throughout the lifecourse and this introduces questions regarding the mechanisms through which exposures to certain nutritients are retained. Epigenetics involves changes to the genome that do not involve the primary DNA sequence. These changes are marks upon the genome, such as DNA methylation, histone modifications and noncoding microRNAs, which are copied from one cell generation to the next. Involved in gene expression, epigenetic marks are important in maintaining cellular health and it is thought that instability of these marks may contribute to aberrant gene expression and a decline in optimal health, contributing to the ageing process. DNA methylation has been mainly shown to decrease in its content across the genome with ageing contributing to instability of the chromosome and tumour formation. On the other hand, typically unmethylated domains can undergo an age-related increase in methylation with a loss of expression of particular genes to the detriment of cell health. Mounting evidence suggests that dietary factors, including specific nutrients, can shape the epigenome. Dietary exposures such as high fat, low protein or energy restriction and, more specifically, variation of particular micronutrients or non-nutrient components of the diet (i.e. folate or polyphenols) can alter epigenetic activity. To a large extent, the relationship between nutrition and ageing through epigenetics remains undiscovered; however, the introduction of novel model organisms such as the honeybee may contribute to elucidation of the fundamental mechanistic relationships and generate potential epigenetic biomarkers translatable to humans. Unlocking the key to the epigenome and its complex interaction with nutritional factors may facilitate dietary recommendations to promote healthy ageing.