Intermittent fasting diets are all the rage these days. We are seeing everything from the conservative 5:2 diet to more extreme fasting methods gaining prominence in Silicon Valley circles, but while there has been plenty of observational research pointing out the correlation between fasting and positive health outcomes, we still don't have a good understanding of any underlying biological mechanism at play.

A new study from Harvard researchers has now shown how fasting can increase lifespan, slow aging and improve health by altering the activity of mitochondrial networks inside our cells.

"Although previous work has shown how intermittent fasting can slow aging, we are only beginning to understand the underlying biology," says William Mair, senior author on the study.

Mitochondria are a little like tiny power plants inside our cells. Last year a team of researchers led by Newcastle University successfully showed how mitochondria are fundamental to the aging of cells. The new research from Harvard shows how the changing shapes of mitochondrial networks can affect longevity and lifespan, but more importantly the study illustrates how fasting manipulates those mitochondrial networks to keep them in a "youthful" state.

Inside cells mitochondrial networks generally alternate between two states: fused and fragmented. Using nematode worms, an organism useful for studying longevity as it only lives for two weeks, the study found that restricted diets promotes homeostasis in mitochondrial networks allowing for a healthy plasticity between these fused and fragmented states.

Above we can see mitochondrial cells in muscle tissue from the nematode worms Harvard Chan School

"Our work shows how crucial the plasticity of mitochondria networks is for the benefits of fasting. If we lock mitochondria in one state, we completely block the effects of fasting or dietary restriction on longevity," says Mair.

The study also found that fasting enhances mitochondrial coordination with peroxisomes, a type of organelle that can increase fatty acid oxidation, a fundamental fat metabolism process. In the study's experiments, the lifespan of the worm was increased by simply preserving mitochondrial network homeostasis through dietary intervention. These results help shed light on how fasting can increase longevity and promote healthy aging.

"Low-energy conditions such as dietary restriction and intermittent fasting have previously been shown to promote healthy aging. Understanding why this is the case is a crucial step toward being able to harness the benefits therapeutically," explains Heather Weir, lead author of the study.

"Our findings open up new avenues in the search for therapeutic strategies that will reduce our likelihood of developing age-related diseases as we get older."

The study was published in the journal Cell Metabolism.

Source: Harvard University