What do mitochondrial mutations mean for how fast you age?
Mutations in the DNA of your cells' energy-producing structures build up as you age and disrupt how those cells make energy. Which inherited variants you carry matters: some are linked to a longer lifespan.
Mitochondria are the power generators of your cells. They carry their own DNA, and when that DNA accumulates mutations, the energy-production system works less well. This disrupted energy production affects almost every cell function and is seen as one of the core processes of ageing.
As you get older, small fragments of lost DNA from your cells' energy-producing structures build up in muscle cells. That build-up goes hand in hand with more internal inflammation and reduced protein production, two patterns typical of aged tissue. Whether these mutations cause ageing or are simply a consequence of it has not yet been proven. Eating less, specifically a 25% reduction in calories for two years, did not noticeably reduce that build-up in muscle cells.
Not all inherited variations in mitochondrial DNA are harmful. Certain variants appear unusually often in centenarians in Japan, China, Turkey and India. One variant in a gene involved in energy transfer (the ATP6 gene) is linked not only to a longer lifespan but also to a lower risk of Parkinson's disease, and it has not been connected to known illnesses. That makes it relatively interesting, though these are associations, not proven causes.
At a molecular level there are also protective processes: young cells contain large amounts of a particular type of molecule that helps the cells' energy-producing structures work properly. In old cells, those molecules are far less abundant. When the protein that keeps them stable disappears, cell ageing visibly accelerates, at least in laboratory studies. This is promising but still a long way from practical applications.
NAD supplements, which support energy production inside cells, are being studied as a way to slow the decline of those energy-producing structures. Animal studies and early studies in people show positive signals, but long-term data from people are largely lacking. There are also possible risks: a build-up of waste products, and in theory the promotion of tumour growth or accelerated cell ageing. If you are considering NAD supplements because of an underlying condition, discuss this with your doctor.
This answer draws on two combined reviews of previously published studies, plus three additional studies not yet further classified. The findings on mutation build-up and disrupted energy production are supported by multiple sources. The findings on specific variants and centenarians, on protective RNA molecules, and on NAD supplements rest on a thinner base: small studies, animal research, or a single theoretical model. For most findings, cause and effect have not been established; they are associations seen in people or effects observed only in the laboratory or in animals.
Does chronic inflammation accelerate the ageing of your cells?
Chronic inflammation demonstrably accelerates cellular ageing through a negative spiral that is difficult to break. The best evidence-based approach to tackling that spiral is through lifestyle factors that dampen low-grade inflammation, such as sufficient exercise and a diet low in ultra-processed products.
Can meditation do anything about ageing at the cellular level?
Meditation appears to activate an enzyme that protects chromosome caps from ageing, although the studies are still too small to draw firm conclusions. Meditation is in any case safe and has positive effects beyond cell biology, so the barrier to trying it is low.
What do zombie cells do to your ageing?
Zombie cells accumulate as you age and accelerate ageing through inflammatory signals; how to tackle them is promising but still very much under investigation.
Why do some cells stop dividing as you age?
Cells stop dividing because their chromosome tips wear down and they accumulate DNA damage: a protective mechanism that in later life becomes harmful precisely because the stalled cells build up. Treatments that address this are still under active investigation and are not ready for self-application.
What is the role of inflammation in cellular ageing?
Inflammation and cellular senescence reinforce each other in two vicious cycles, leading to tissue damage and age-related diseases. Both protecting your cells against oxidative damage (think sun protection and lifestyle) and future targeted therapies aim to break this cycle.
What exactly does senescence do to your cells as you age?
Senescent cells stop dividing and secrete inflammatory substances that damage tissues over time. They are necessary in youth, but when they accumulate they accelerate ageing and disease.