Each week, we read what's going on the world of science and bring the wildest findings straight to you. Here's the latest:
Just being told DNA test results can change your body, even if they’re not true
It’s easier than ever to get personalized DNA information—perhaps you’ll even give or receive a 23andMe-like kit this holiday season. These tests might inform you about small variations in your DNA that are associated with either positive or negative health effects, but what if simply receiving these genetic results was enough to change your health?
In a new study published in Nature Human Behavior, the findings suggest that genetic information can affect us in this way. Study participants’ bodies changed in ways that mirrored whatever genetic information they were told about, regardless of their real genetic risk profiles.
“Receiving genetic information doesn’t just make you more informed,” says Alia Crum, assistant professor of psychology at Stanford University, and senior author of the new study, in a release. “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.”
The researchers took DNA samples from people who were told that the study was about the relationship between DNA and diet. Then, some of the subjects did an exercise test and some ate a meal, while also being tested for a gene associated with obesity and for a gene associated with exercise capacity.
Next, participants were told what their genetic risks were—but only some of the people were told accurate information. “Some of those with genes that protect them from obesity or gave them higher exercise capacity were told they had a higher risk version of the gene, and vice versa,” the press release explains.
When they repeated the meal and exercise tests, the subjects who were told they had a gene that made them predisposed to feeling full, actually did feel more full, whether or not they truly had that gene. (Those participants felt more full compared to their own ratings of their fullness a week before, before they “knew” of their genetic results.)
Amazingly, these responses went beyond a perception of fullness; they had an immediate physical response too: A fullness protein called glucagon-like peptide 1 was released into the blood at a level 2.5 times greater than before they were told about their genetic risk.
“Interestingly, these effects were greater than the effects due to people’s actual genetic risk,” first author and graduate student Bradley Turnwald tells me. “This means that the risk level that we randomly chose to tell people was more influential for their feelings of fullness and their gut peptide response than people’s actual genetic risk in this case.”
The people who were told that they were genetically at risk for poor exercise capacity showed reduced lung capacity and couldn’t run as long as they could before they were told about their “risk.” They also had a decreased ability to exchange CO2 buildup for oxygen.
The results show how powerfully a person’s mindset can affect their body, and how mindsets can be changed with new information, like genetic “results.” We know this already from placebo and nocebo studies, Turnwald tells me, but the effect may be more pronounced with genetic information. People tend to think of genes as permanent and unchanging compared to many other markers of health, like cholesterol or blood pressure.
It’s important for clinicians and scientists to recognize how genetic results can affect a person who is receiving them, and for us to remember that genes are certainly not everything. “Information should be given in a way that maximizes the potential benefits on physiology for those who learn that they are protected, and minimizes potentially negative effect of the mindset that one is at risk,” Turnwald says.
Gratitude meditation might make stress harder to handle for new meditators
Meditation and mindfulness are often promoted as a treatment for all kinds of mental and health problems, but it doesn’t always work for everyone. This might be because there are many forms of meditation, and different styles can lead to different benefits. Yet it’s still most often recommend as one monolithic practice.
In a new study in PLOS One, researchers examined different types of mindfulness-based interventions to see what kinds of distinct outcomes they had in people with no previous experience with meditation. “Understanding more about the specific impact of different practices may help us design better interventions and potentially predict who will respond positively or negatively to a given practice type, especially upon introduction,” says first author Matt Hirshberg, a postdoctoral research associate at the Center for Healthy Minds at University of Wisconsin Madison.
They looked at mindfulness-based interventions like breath awareness, loving-kindness, gratitude practices, and attention control. These were chosen because they are all commonly used, but thought to have different benefits. Hirshberg was surprised to find that the gratitude practice enhanced the negativity response to a stressor compared to the other kinds of meditation.
The stressor was called a “the cold pressor test”— people were asked to keep their hand up to the elbow in an ice bath for three minutes “while being observed at a close distance by an unexpressive experimenter wearing a white laboratory coat recording time,” the paper says. It induces both psychological and physical stress.
People in the gratitude meditation group reported that stress was more aversive and had larger increases in negative emotion related to stress. They don’t yet know why a gratitude practice would increase reactivity to stress, Hirshberg says, but one theory is that because gratitude involves remembering a time when you felt grateful, it could increase your inward focus on yourself and your perspective.
“Once stressed, because awareness of self has been centered, the stressful experience may become more entwined with this awareness of self, making the experience even more stressful,” Hirshberg tells me. “We might think of this as akin to the difference between ‘I am so stressed out! When is this going to end!’ versus ‘This is unpleasant.’”
The different types of meditation need to be studied more fully to appreciate all of these subtle differences. But Hirshberg thinks that if you are new to meditation, perhaps you shouldn’t do a gratitude practice if you know you’re going to be facing some stress soon after.
“For example, you may not want to induce a state of gratitude immediately before a high stakes test or a job interview,” he says. “In those cases, you may be better off resting attention on the breath or generating feelings of goodwill towards others, as these techniques may help mitigate the stressful experience rather than heighten it.”
There’s a potential new drug for cannabis use disorder
Cannabis use disorder (CUD) affects around 13 million people worldwide, but many people don’t know it exists. The Diagnostic and Statistical Manual, or DSM5, list several criteria for CUD, including: wanting to cut down or stop using but not being able to, having cravings and urges for weed, not managing to get things done at school, work, or home; continuing to use even when it’s causing problems in your relationships, developing a tolerance to weed and needing to use more to feel high, and getting withdrawal symptoms when you do stop, which are only relieved by using more.
In the US, around a third of all current cannabis users meet these diagnostic criteria, and more than 250,000 people were admitted for treatment of cannabis abuse treatment in 2016.
“That is not a trivial number,” says Deepak Cyril D’Souza, a professor of psychiatry at Yale University School of Medicine. “[The number of treatment admissions] was second only to heroin. However, there are no FDA-approved treatments for CUD, and there are no other existing medications that clinicians have found to be consistently effective or safe in treating CUD.”
In a study published in The Lancet Psychiatry, a phase 2 randomized trial of 70 men showed that a new experimental drug could help reduce withdrawal symptoms and help people with CUD stop using.
The drug is a fatty acid amide hydrolase, or FAAH inhibitor called “PF-04457845.” Basically, the drug blocks the enzyme that breaks down the brain’s own cannabis-like chemical called anandamide. When it blocks this enzyme, it increases anandamide. The people who were given the drug, and not the placebo, had fewer withdrawal symptoms, used cannabis less, had less THC in their urine, better self-reported sleep, and better sleep architecture as measured by brain wave monitoring.
“With the growing legalization of cannabis worldwide, it is only reasonable to assume that the rates of cannabis use disorder will go up,” says D’Souza, the first author of the paper. “The latest survey of high school students by the Substance Abuse Mental Health Treatment Services Administration (2018) showed that cannabis use was highest in those states that legalized cannabis.”
How can we both recognize the potential beneficial and therapeutic effects of cannabis while recognizing the growing risks? D’Souza says that there needs to be more rigorous randomized, double-blind, placebo-controlled with adequate sample sizes to test the effects of cannabis and all its compounds.
“But we need to do those kinds of studies before we can make any conclusions,” he says. “So the bottom line is that like all other potential medicines we need to weigh the risks and benefits of the potential medicine based on scientific evidence, and not public opinion.”
Your weekly health and science reading list
'Before, I was quite a shy person': life after brain damage. By Sirin Kale in The Observer.
The stories of people whose memories, personalities, and experiences change after a brain injury– but not necessarily in a bad way.
Why are so many people getting a meat allergy? By Maryn McKenna in Mosaic.
It’s called ‘alpha-gal allergy,’ it's caused by a tick bite, and it’s turning people into reluctant vegetarians
23andMe Informed Me My Husband and I Are Related. By Liane Kupferberg Carter in The Cut.
“I discovered that my husband Marc and I are related through more than mere marriage. We’re third cousins.”
Is Listening to a Book the Same Thing as Reading It? By Daniel T. Willingham in The New York Times.
I listened to my first audiobook recently, and had a tough time paying attention. Am I just a book snob, or is there a big difference between reading and listening? Willingham explains.
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