Eat Less Food, Epigenetic Drift May Extend Lifespan

Lewis Katz School of Medicine at Temple University (LKSOM) have discovered “age-related methylation drift.”

For over a hundred years, scientists have known that excessive calorie intake and obesity decreases our life-span, and conversely lowered caloric intake could extend both quality and quantity of life.

Jean-Pierre Issa, MD, senior investigator and Director of the Fels Institute for Cancer Research at LKSOM, stated “Our study shows that epigenetic drift, which is characterized by gains and losses in DNA methylation in the genome over time, occurs more rapidly in mice than in monkeys and more rapidly in monkeys than in humans. Methylation patterns drift steadily throughout life, with methylation increasing in some areas of the genome, and decreasing in others.”

DNA methylation is the suppression of gene expression through the addition of methyl groups to DNA. The researchers looked at DNA methylation patterns in cord blood at birth from mice, monkeys, and humans, at different ages. The results revealed increases in methylation in older animals and people, compared to unmethylated sites in younger individuals at the same genome site. They reported that, “Epigenetic drift is conserved across species and the rate of drift correlates with lifespan when comparing mice, rhesus monkeys, and humans.”

In areas with increased methylation there were dramatic losses in gene expression as the animals got older. Inversely, genes with reduced methylation revealed increased gene expression. The researchers discovered that the greater the epigenetic change, the faster it happened; which resulted in a shorter lifespan. “We propose that epigenetic drift is a determinant of lifespan in mammals,” they said.

In addition, they wondered if they could increase longevity through manipulating the epigenetic drift through caloric restriction, which is known to increase lifespan in most mammal species.

Researchers cut calorie intake by 40 percent mice and by 30% in middle-aged monkeys, resulting in major decreases in epigenetic drift. With this modification of calories, the DNA methylation changes in older animals were very similar to those of younger animals of the same species. “The impacts of calorie restriction on lifespan have been known for decades, but thanks to modern quantitative techniques, we are able to show for the first time a striking slowing down of epigenetic drift as lifespan increases,” Dr. Issa said.

There is much more investigation to do regarding methylation drift in DNA to see how it effects aging and life extension. Other areas of research for drift may relate to various age-related diseases such and cancer, heart disease and diabetes.