Nature Human Behaviour

Learning The Results of a DNA Test Could Actually Change The Way Your Body Works

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Last year, uptake of home DNA tests sailed into the stratosphere, giving millions of people around the world a whole new level of insight into the ways their genes work, and helping predict their genetic risk for disease.

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But knowledge is a dangerous thing. New research suggests this kind of genetic knowledge isn’t just informative, but can also be transformative – with DNA results conferring a kind of genetic placebo effect that actually impacts how people’s bodies function.

“Receiving genetic information doesn’t just make you more informed,” explains psychologist and senior researcher of the new study, Alia Crum from Stanford University.

“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.”

In an experiment, the researchers took DNA samples from over 200 participants. Then, the group was divided into two smaller groups, each with more than 100 members.

One of these groups performed an exercise test on a treadmill, while the other group ate a small meal.

A week later, the participants returned for a repeat of their exercise (or meal-eating) experiment, but with a crucial difference. This time, before doing the second test, they were given information on the results of their genetic test – with a catch.

Specifically, instead of telling the participants their real genetic results, they were told random results. The exercise group was informed they either possessed a gene variant associated with poorer aerobic exercise capacity, or a gene that gave them extra endurance.

Similarly, one half of the eating group was randomly informed they could be genetically predisposed to obesity due to a gene variant that made it harder to feel full after eating; the others being told their genes promoted feelings of satiety, helping protect them from obesity.

After being given these deceptive, random results – that bore no relation to the people’s actual genotype – the mere conveyance of this false information affected how they performed in their next tests.

Those on the running machine who had the impression their aerobic capacity was impaired, struggled to run – and quit sooner than on their first test. Those who believed they had the protective gene variant, on the other hand, performed about the same.

In the eating test, those who were told they could be predisposed to obesity did about the same as before, rating their levels of fullness similarly, and producing similar levels of a fullness hormone in their blood.

But the participants who were told they were protected from obesity by virtue of their satiety-promoting gene actually produced about 250 percent more of the fullness hormone in their blood than in the blind test a week before.

“It was really a much stronger and faster physiological satiety signal, and this mapped on to how much more full participants said that they felt,” first author of the study, Bradley Turnwald, explains.

So what does this tell us? The researchers are eager to emphasise it doesn’t mean getting your genome sequenced is a bad idea, but they say people need to be aware that the genetic information itself can have a measurable effect on our physiology, even if we’re not genetically predisposed to certain things.

“The take-home message here is that the mindset that you put people in when you deliver genetic risk information is not irrelevant,” Crum says.

“The mindset of being genetically at risk or protected can alter how we feel, what we do and – as this study shows – how our bodies respond.”

With everything we know about the placebo effect and its mysterious powers over our bodies and minds, it’s no wonder that genetic information can be suggestive too, others have noted.

But given the ongoing explosion in consumer DNA sequencing, this is one important side effect people need to be aware of – after all, nobody reads their genome results in a vacuum.

“Although much remains to be explored, the present research represents a major advance in our understanding of the impact of genetic risk disclosure and suggests that learning of one’s genetic risk of obesity may in fact exacerbate one’s risk,” the authors write.

“The results herein underscore the critical need to accompany biological advances in genetics with an equally sophisticated understanding of the impact of receiving genetic risk information on patient health outcomes.”

The findings are reported in Nature Human Behaviour.

This Is How Much Money You Need to Be Happy, According to Science

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But not too much!

They say money can’t buy happiness, but let’s be honest, they say a lot of things – and they’re not always right.

When it comes to income, scientists say there actually is an ideal yearly amount we can earn to feel emotionally content and satisfied – and believe it or not, if you have too much money, you may actually start creeping back into unhappy territory.

“That might be surprising as what we see on TV and what advertisers tell us we need would indicate that there is no ceiling when it comes to how much money is needed for happiness, but we now see there are some thresholds,” explains psychologist Andrew T. Jebb from Purdue University.

Jebb and his team analysed data from the Gallup World Poll, an international survey of more than 1.7 million individuals from 164 countries.

When they examined participants’ responses on questions relating to life satisfaction and well-being – measures of what’s called subjective well-being (SWB) – they discovered the magic number for ‘income satiation’ is a global phenomenon, but one that varies considerably around the world.

Nonetheless, when you average the results out, we now have a rough idea of just how much $ = 🙂 in US dollars.

“We found that the ideal income point is $95,000 for life evaluation [overall life satisfaction] and $60,000 to $75,000 for emotional well-being [day-to-day happiness],” Jebb says.

“Again, this amount is for individuals and would likely be higher for families.”

Of course, the global average masks how satiation points are significantly higher in some countries than in others, broadly associated with how wealthy each nation is comparatively.

Life satisfaction costs $125,000 in Australia, $105,000 in North America, and $100,000 in Western Europe – but only $70,000 in Southeast Asia, $45,000 in Eastern Europe, and $35,000 in Latin America.

Globally, it’s cheaper for men to be satisfied with their lives ($90,000) than women ($100,000), and for people of low ($70,000) or moderate education ($85,000) than people with higher education ($115,000).

Perhaps the most remarkable thing about the study is how it highlights that once you’ve hit income satiation, you may want to freeze your earning capacity right there.

“Another important phenomenon within our data was the presence of turning points at which income levels after satiation saw consistent decrements in happiness,” the authors explain.

“It has been speculated for some time that very high incomes may lead to reductions in SWB.”

The authors detected this phenomenon in their own results, but noted it was only evident in terms of life evaluation (not emotional well-being), and limited to just five of the nine regions considered in the study: Western Europe/Scandinavia, Eastern Europe/the Balkans, East Asia, Latin America/the Caribbean, and Northern America.

As for why the pattern isn’t found elsewhere, we don’t know for sure, but the researchers speculate it’s associated with the demands that come with higher wages.

“Theoretically, it is presumably not the higher incomes themselves that drive reductions in SWB, but the costs associated with them,” the researchers write.

“High incomes are usually accompanied by high demands (time, workload, responsibility, and so on) that might also limit opportunities for positive experiences (for example, leisure activities).”

If that’s the case, it gels with a lot of other research that’s shown money buys happiness but only if you have free time to enjoy it, by spending it on the right things, and not prioritising money over time.

There’s lots of ways to encourage feelings of happiness in your daily existence, but make sure you don’t buy into the most common misconceptions about where smiles come from.

There’s no enjoyable shortcuts here folks, but the good news is we’re all getting more happy all the time – in a manner of speaking, anyway – because old folks are some of the happiest folks around.

Source:  Nature Human Behaviour.