Unpicking the links between dietary restriction and ageing

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The effects of reduced food consumption and lifespan extension have been observed in many species, including primates, but the biology behind how this is achieved is poorly understood. Researchers at the Max Planck Institute for Biology of Ageing, Cologne, Germany, the Cluster of Excellence for Aging Research CECAD, Cologne, Germany and the Babraham Institute, Cambridge, UK, have found that in mice, dietary restriction is strongly protective against age-related changes to our DNA. The results, published in Genome Biology, pave the way for understanding how age-related alterations to our epigenomes may have long-term consequences for gene expression and organ function, and how dietary restriction may prevent these changes.

We are more than our genomes – the order of the letters (ATGC), known as bases, in our DNA. On top of this sequence is another layer of control - our epigenome -  which, by a process of adding or removing tags to our DNA and by altering DNA packaging inside our cell nuclei, controls which genes are on or off in different cell types. Our epigenome is known to be influenced by external factors including diet, making it a prime candidate linking dietary restriction and longevity.

The researchers found that restricting the food intake of mice to 40% of their counterparts resulted in a 30% increase in lifespan. They looked across the whole mouse genome to profile the epigenetic changes to DNA occurring in response to this dietary restriction and which might explain the lifespan extension. They found that dietary restriction controlled genes involved in establishing one type of epigenetic change – the tagging of specific DNA bases with a small chemical group (called DNA methylation). The result was that age-related changes to DNA methylation across the genome were substantially prevented by dietary restriction.

Oliver Hahn, PhD Student in the Partridge Group at the Max Planck Institute for the Biology of Ageing and lead author of the study said “Our research has identified physiologically meaningful epigenetic changes occurring during ageing. Dietary restriction partially protects against age-induced methylation changes whilst simultaneously instigating the reprogramming of lipid metabolism genes which seems to result in beneficial changes to which help our bodies function better”.

In addition to profiling the effects of dietary restriction on age-related changes to DNA methylation, the researchers also discovered a link between dietary restriction and the epigenetic repression of genes involved in lipid metabolism. Physiologically, the reprogramming of lipid metabolism caused by dietary restriction protected organisms against age-related increases of fat deposits in the liver and the development of hepatic insulin resistance, a feature of age-related type 2 diabetes.

Professor Wolf Reik, Head of the Epigenetics programme at the Babraham Institute, said:
“This work significantly advances our understanding of epigenetic regulation of ageing and dietary restriction by connecting the epigenome more directly with lipid changes associated with healthy ageing. Future work may reveal if dietary restriction leaves a long term epigenetic memory in the genome.”

Original publication:
Oliver Hahn, Sebastian Grönke, Thomas M. Stubbs, Gabriella Ficz, Oliver Hendrich,  Felix Krueger, Simon Andrews, Qifeng Zhang, Michael J. Wakelam, Andreas Beyer, Wolf Reik,  Linda Partridg
Dietary restriction protects from age-associated DNA methylation and induces epigenetic reprogramming of lipid metabolism.
Genome Biology, March 2017