Do sirtuins actually do anything against ageing?
Sirtuins play a clear role in ageing in animal research, but whether they are of any benefit to humans (through supplements or other means) remains unknown. Wait for human evidence before acting on any sirtuin-based claims.
Sirtuins are a family of seven proteins that have a hand in many ageing processes: they regulate metabolism, protect DNA, suppress inflammation and safeguard the stability of genetic material. In yeast and other simple organisms they demonstrably slow ageing, but whether that also holds true in humans has not yet been proven.
Of the seven, SIRT1 and SIRT6 have been studied the most. Animal studies and laboratory research show that SIRT1 is active in the cell nucleus and regulates metabolism, and may be protective for the heart, blood vessels and nervous system. SIRT6 safeguards the stability of genetic material and suppresses inflammation. Animal research points to therapeutic potential, but convincing evidence in humans is still lacking. Furthermore, the role of SIRT1 in DNA repair is a double-edged sword: it activates some repair processes while suppressing others. That nuances the picture of it being 'simply protective'.
Sirtuins are also regarded as the link that explains why eating less extends lifespan in animal models. They become more active during caloric restriction and appear to relay those effects to blood vessels, muscles and the nervous system. But even this connection is disputed in yeast, and it has never been demonstrated in humans. The hypothesis that exercise works in part through sirtuin-regulated pathways (energy metabolism, antioxidant activity, the brain) is biologically plausible, but here too the exact contribution of sirtuins has not been established.
Resveratrol, the compound found in red grape skins, is being investigated as a means of activating sirtuins. The evidence for this is limited and controversial: studies still contradict each other too much to say anything meaningful about it at this stage. SIRT4 has barely been studied. SIRT7 protects genomic integrity in animal and cell studies, but human evidence is scarce here as well. An added complication: the effect of sirtuins on lifespan appears to vary by tissue type and by protein quantity, which makes translating findings into a treatment particularly difficult.
All sources are reviews; no randomised trials or meta-analyses are available. The mechanistic and animal-experimental evidence is relatively robust, but human evidence is largely absent.
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.
Does clearing out senescent cells with senolytics help against ageing?
Senolytics show impressive results in animal studies, but in people the evidence is too thin for use outside a research setting. Self-medicating with Dasatinib is inadvisable given its side effects and the risks around tumour growth.
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.
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.
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.
Can you counteract DNA damage from ageing through your lifestyle?
Quitting smoking, exercising regularly and eating plenty of vegetables demonstrably reduce DNA damage; antioxidant supplements are unlikely to help with this.