Manipulating the mitochondrial network that resides inside our cells, either by dietary restriction or genetic manipulation, may promote health and even increase lifespan, according to new research from the Harvard T.H. Chan School of Public Health.
Recently published in Cell Metabolism, the study highlights the biology involved in cells’ declining ability to process energy over time, a decline that eventually leads to various age-related diseases. It also explores how periods of intermittent fasting can promote healthier aging and thus longevity.
How Does This Process Work?
Mitochondria are the structures in your cells that produce energy, and they exist in networks that change shape depending on the energy demand they face. This elasticity declines with age, however, and the reason why this happens has been a mystery, at least until now. In this new study, researchers were able to show a casual link between the changes in mitochondrial network shape and longevity.
Using nematode worms, which have a lifespan of only two weeks, researchers were able to study aging in real-time in the lab. While mitochondrial networks usually alternate between fragmented and fused states, researchers found that by restricting the worms’ diet and mimicking dietary restriction by using an energy-sensing protein called AMP-activated protein kinase (AMPK), they could maintain the fused mitochondrial networks — those in a more “youthful” state. They also determined that these more youthful networks increased lifespan by directly communicating with organelles called peroxisomes to modulate fat metabolism.
“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,” said Heather Weir, lead author of the study, who conducted the research while at Harvard Chan School. “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.”
“Although previous work has shown how intermittent fasting can slow aging, we are only beginning to understand the underlying biology,” said William Mair, associate professor of genetics and complex diseases at Harvard Chan School and senior author of the study. “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.”
They then explored the role that mitochondrial networks have in the effect of fasting in mammals, and whether mitochondrial inflexibility might explain the association between obesity and the risk of age-related diseases.
So, What Is Intermittent Fasting, and Can It Help You?
Intermittent fasting is the process of restricting your eating to an 8-10 hour period. So, if you choose to eat from 12 p.m. – 8 p.m., you must fulfil all your caloric needs within this window and refrain from eating the rest of the day. If you are thinking this sounds difficult, it’s because it goes against much of what we have been taught to believe about our energy needs, including the notion that breakfast is the most important meal of the day. Transitioning to this schedule may be difficult at first, since it marks a dramatic change from what most of us are used to, but it is possible to adapt with time. There is also a good chance you will start to notice the benefits quickly, which will motivate you to stay on track.
It should be noted that most people recommend a wider fasting window for women — 14-16 hours — so a woman’s fasting schedule will look a little different. Our hormones function differently and therefore our bodies have different requirements, too.
This isn’t the first study to show the benefits of intermittent fasting, which include weight loss and immune system regeneration, and we have covered this topic extensively in the past.