What is epigenetics, and can you influence your own genes?
Epigenetics determines which genes are active and is, in principle, open to influence. In medicine, epigenetic mechanisms are already being successfully targeted in some blood cancers, but evidence for self-directed change through lifestyle remains limited in people.
DNA methylation, histone modification and microRNA are the three main epigenetic mechanisms. They determine which genes are switched 'on' or 'off', without changing the DNA sequence itself. Think of it like sticky notes on a book: the text stays the same, but the markings decide which passages actually get read. This kind of control is largely passed down through generations and applies to every cell in your body.
Epigenetic disruptions have a demonstrated role in the development of disease. When these systems go out of balance, they contribute to autoimmune diseases, cancer and other conditions. In breast cancer, for example, shifts in the epigenome can cause tumour cells to become resistant to hormonal treatment. In asthma, cell-specific methylation patterns have been found that are linked to lung function, though it is not yet fully clear whether those patterns cause the disease or are a consequence of it.
The good news is that epigenetic disruptions are, in principle, reversible. That is a crucial difference from genetic mutations, which permanently alter your DNA. This reversibility is what makes epigenetics an interesting target for medicines. Drugs that act on epigenetic mechanisms have already been proven effective in people with certain lymphomas and a precursor condition to leukaemia. For solid tumours the picture also looks promising, but the evidence there is still thinner.
Ageing is accompanied by measurable shifts in your epigenome, particularly in how your DNA is marked. These changes are linked to how quickly you age biologically and how long you stay healthy. Researchers are testing ways to slow this process, but the results so far come mainly from animal studies and early studies in people. It is therefore too soon to say that you can actively steer your own epigenetic ageing.
Claims are based on five to nine sources, including review articles on the basic biology of epigenetics, studies in people on epigenetic drugs for blood cancers, and early mechanistic research into epigenetic ageing. Strongest evidence: the basic workings of the mechanisms and their clinical use in blood cancers. Weakest evidence: rejuvenating interventions in people.
Can you repair DNA damage, or can you only prevent it?
Your body actively repairs DNA damage through multiple well-studied mechanisms, but that repair is not always perfect and becomes less effective when the cell is under excessive strain or grows older.
Can you read your disease risks from your DNA?
Your DNA and certain proteins in your blood give a useful picture of your predisposition to heart disease and other common conditions, but in people of non-European descent those scores are less reliable.
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.
Can you protect your DNA from damage through diet?
Diet can both protect and damage your DNA, but the protective effects of supplements often fall short in practice. Make sure you are not deficient in zinc, folate and selenium, eat plenty of vegetables and fruit, and avoid supplements containing high doses of beta-carotene, especially if you smoke.
Can DNA damage in your cells repair itself?
Your cells repair DNA damage continuously and systematically, but the system is not infallible: chronic overload or a defect in the repair routes increases the risk of cancer and age-related diseases.
Can you lengthen or restore your telomeres?
Healthy adult body cells cannot lengthen their own telomeres, and no proven safe way to do so from the outside yet exists. Be sceptical of supplements or therapies that promise otherwise.