Which matters most - genes or lifestyle?
Do the choices you make every day really improve your chance of a long and healthy life, or is your health written in your genes?
The news is full of reports that scientists have found 'the gene for obesity' or other genes that affect health. So is there any point in exercising and eating your greens?
Definitely, say the experts. Health comes down to a mix of factors - the genes you inherit from your parents play a part, but how you look after your body matters more.
Genes, environment and lifestyle
UK Biobank is a huge research project set up to answer some of the questions about genes versus lifestyle. It has collected data on half a million people in the UK, including their genetic profiles, lifestyles, diet, activity levels, occupation and health history. So far, says director Professor Rory Collins, scientists have discovered that inherited genes have a fairly small effect for most people.
"What is emerging is a lot of genetic variations that produce a small effect on the risk of disease. With certain diseases and certain genetic abnormalities, they will have a big effect. But the vast majority will have small effects," he says.
One study from the UK Biobank data looked at which pieces of information about a person could predict most strongly whether they would die during the next 5 years. The information included family history - which could point to the effects of inherited genes - and lifestyle factors such as diet, smoking and exercise.
Leaving aside obvious things like age and already being ill, the single thing that had the biggest effect on people's chances of living beyond 5 years was whether or not they smoked. Overall, lifestyle factors were much more likely to predict who survived and who died than family history. You can calculate your own risk of death in the next 5 years by answering a few questions on the researcher's website and also see how different factors affect this risk.
Chris Allen, senior cardiac nurse at the British Heart Foundation, said it was difficult to tell whether a family history of heart disease was down to inherited genes, or to people in the same family sharing the same habits - for example, how much they exercise, whether they have a healthy weight, and what they eat. Although some people do have inherited conditions - for example a condition called familial hypercholesterolaemia, which means you have much higher than usual cholesterol in your blood - there is still something you can do about it.
"You can take control of risk factors [such as smoking, diet and exercise] and give yourself a better chance. It's very rare to have people who have a strong family history of disease and don't have any risk factors that they can take care of," says Chris.