Learning One's Genetic Risk Might Affect Eating and Exercise

Posted on February 2, 2019

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Learning and exploring one’s genetic make up has been become increasingly more accessible through commercial companies which leads to its subsequent increase in popularity as well. However, with the rise of precision medicine and a greater public awareness of genetic risk of medical conditions, many are tracking their genetic make up more specifically to learn of their propensity for certain disease and disorders. This can greatly trigger emotional and behavioural changes, affecting one psychologically. On top of that, a recent study has shown that learning about such information can have a physiological influence as well even if what is told is not entirely accurate.

The study was conducted by asking participants to get a baseline measure of their cardiorespiratory physiology through running on a treadmill. A week later they would repeat the treadmill test but some were told they had a high-risk form of a particular gene (CREB1), that linked to poorer aerobic exercise capacity and fewer cardiovascular improvements when working out, while others were told they have the protective form of CREB1. This information was relayed to the participants regardless of what their actual genotypes were. Awareness of this information had the power to influence individuals physiologically such that those who were told they were at high risk displayed significantly physiological change that signalled decrease exercise capacity, and they stopped running significantly earlier than their first run. Psychologically, they also felt more worried and less in control of their exercise capacity. This physiological change was absent in those who were told had they protective gene, but they did run significantly longer than their first test.

As this information were not entirely accurate, the changes observed were subjective in nature. In the protective group, it was a placebo effect while in the high-risk group, it resulted in what is know as a nocebo effect. A nocebo effect is when learning about possible negative outcomes makes them more likely to occur. These effects typically are thought of in terms of taking medication but information itself can result in them as well, affect them not just psychologically but physiologically as well.

The results of this study were replicated in a similar one concerning the FTO gene, a genetic risk factor for obesity where the high-risk form is associated with people feeling full more slowly than others, and lower levels of a gut peptide that signals satiety to the brain (GLP-1). The study structure follows closely to the first, but instead of the treadmill test, participants consumed a 480-calorie meal. Those who were told had the protective form of FTO reported a 1.4-fold increase in how full they felt after eating as compared to their baseline session. The high-risk group did not change as much but similarly felt more worried and less in control over how full they would feel.

These two studies exhibit the power of mindset as just thinking one had a specific genotype resulted in a powerful physiological or behavioural effect than actually having that genotype. This study then highlights the risk of seeking out one’s genetic risk as it shows how easy it can result in a self-fulfilling prophecy. Additionally, it shows the power of language, as the researchers believe that framing low-risk as protective could have been what led to the positive outcomes.

The main takeaway of this study is then not the discourage people from learning about their genetic risk, but more towards shifting the focus on how these genetic risks can be more effectively presented to both high and low/protective risk individuals.

Note: Each participant was full debriefed before leaving the study to minimise the time participants spent believing the potentially false information they were told.

Category(s):Health / Illness / Medical Issues, Health Psychology

Source material from Psychology Today