DNA test results can become a ‘self-fulfilling prophecy’

Scientists are warning that a DNA test can make people develop physical problems if they are falsely told they have bad fitness genes. Scientists at Stanford University conducted the study on more than 200 people and took DNA samples to test for genes linked to exercise and fullness. They then gave some people the wrong information about their genetic risk. People told they had bad genes for keeping fit became worse at running, and their lung capacity reduced. Conversely, people told they were less prone to obesity were said to feel fuller after eating, and actually produced more of a hormone which tells them they have eaten enough. The scientists conclude that DNA tests can become a ‘self-fulfilling’ prophecy.

The study, published in the journal Nature Human Behaviour, says giving someone the results of a genetic test can change their ‘mindset’ and make them feel they are no longer in control of their health. DNA testing for an obesity and exercise gene was selected in this study because these traits are not as ’emotionally charged’ as genes linked to cancer and Alzheimer’s disease. Previous research had showed that people told they are at genetic risk of Alzheimer’s disease start performing worse in memory tests.

Dr Alia Crum, Assistant Professor of Psychology at Stanford, who led the study, said: “Receiving genetic information doesn’t just make you more informed. What this study shows is that it can also have a physiological impact on your body in a way that actually changes your overall risk profile.”

Care needed when delivering DNA test results

The researchers found that some people wrongly told they had certain genes could show physical symptoms even more dramatic than those actually caused by those genes. Out of a group of 116 people, those told to run on a treadmill gave up 22 seconds earlier than they had done previously if told their genes made exercise harder. Their lung capacity was reduced by 2 liters/minute.

In another experiment, 107 people were given the same meal: once before getting their genetic test result and then a week later after receiving their results. Those told a ‘protective’ gene made it harder for them to get fat produced 2.5 times the amount of fullness hormones during the second meal. They felt 40% more full, despite nothing having changed.

Co-author Bradley Turnwald said: “What was consistent in both studies was that those informed that they had the high-risk gene always had a worse outcome than those informed that they had the protective gene, even though we essentially drew out of a hat which information people received.”

Information can now be garnered on about 10,000 conditions using DNA testing. And advocates of genetests say they can help people live more healthily. But Dr Crum said: “The take-home message here is that the mindset that you put people in when you deliver genetic risk information is not irrelevant. The mindset of being genetically at risk or protected can alter how we feel, what we do and, as thisstudy shows, how our bodies respond. AlphaBiolabs’ DNA testing services are for relationship testing only. To find out about our range call us now on 727-325-2902 or email info@alphabiolabsusa.com.