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?
There are cautious indications that meditation favourably influences the activity of the telomere-repairing enzyme, but whether this truly keeps your cells younger has not yet been convincingly proven. Meditation for stress reduction has a considerably stronger evidence base in any case, and an indirect effect on cellular ageing via that pathway is plausible.
Does clearing senescent cells with senolytics help against ageing?
Senolytics show impressive results in mouse studies, but in humans the evidence is too thin for use outside clinical trials. Self-medication with Dasatinib is inadvisable due to its side effects and cancer-biology risks.
What exactly does senescence do to your cells as you age?
Senescent cells stop dividing, accumulate with age and cause damage throughout the body through a constant stream of inflammatory substances. They are both a protector (a brake on cancer) and a cause of damage, and that makes targeted intervention more complex than it appears.
What do mitochondrial mutations mean for how quickly you age?
Mitochondrial mutations likely contribute to ageing, but exactly how large that contribution is, and through which mechanism, has not yet been definitively established. At this time, there are no proven interventions that can be taken on this basis.
Does caloric restriction actually make your cells younger?
Caloric restriction slows ageing processes in cells, but whether your cells actually become younger as a result has not yet been proven in humans. The metabolic benefits, such as improved insulin sensitivity, have been demonstrated in human studies.
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.