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.
Yes, you can. The most widely used method is the polygenic risk score: the effects of sometimes more than a million small DNA variations are added together into a single number. The higher that number, the greater your genetic predisposition. For heart disease, the 20% of people with the highest score had a more than fourfold higher risk than the 20% with the lowest score. For five conditions at once, including atrial fibrillation, type 2 diabetes and breast cancer, such a score could identify 1 to 8 percent of the population with a more than threefold elevated risk.
There are two serious limitations, however. Most scores have been built using data from people of European descent. In people with a different background they are less accurate and can sometimes even be misleading. In addition, they always express probabilities, never certainties: a high score does not mean you will definitely develop the disease.
Beyond DNA, you can also measure proteins in your blood. Proteins are the substances your genes produce, and their presence reflects what is happening inside your organs. Measuring 5 to 20 proteins turned out to predict the 10-year risk of 67 different diseases better than standard medical information alone. The same approach can also reveal which organs are ageing faster than expected. Nearly 20% of people have one organ that is ageing at a strongly accelerated rate, which raises the risk of death by 20 to 50%. When the heart ages faster than expected, the risk of heart failure rose by as much as 250%.
DNA and proteins together produce even sharper predictions. In people with type 2 diabetes, a model based on nine proteins linked to both diabetes and heart disease predicted future heart disease better than DNA or medical data on their own.
A completely different application is reading the full DNA of newborns to detect rare, serious mutations in a single gene. This can be useful, but interpretation is complicated: by no means do all variants found have a clear meaning, and it is ethically difficult to decide what to report back to parents when risks only become relevant later in life. Research in this area is still at an early stage.
Based on 7 claims with PMIDs: 30309464, 30104762, 31765077, 39039249, 38057571, 40087642, 30576641. Three claims rest on large studies following people for many years (strong quality of evidence), two on moderate evidence, and two on moderate evidence with ethical considerations. All findings concern associations; none of the DNA or protein measurements has been proven to be a cause in an interventional sense.
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 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 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 smoking permanently damage your DNA?
Smoking damages your DNA in multiple ways simultaneously, and some of that damage is permanent; quitting genuinely helps, but does not erase earlier mutations.
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.
What does chronic stress do to your DNA?
Chronic stress accelerates the wear on your DNA protectors (telomeres) in a way that corresponds to years of extra cellular ageing. You cannot prevent this entirely, but limiting prolonged stress is probably one of the most direct ways to slow biological ageing.