Gut bacteria plays a key role in infusing negative feelings in the brains of obese people, causing depression and anxiety, researchers say.
The findings showed that mice on a high-fat diet showed significantly more signs of anxiety, depression and obsessive behaviour than animals on standard diets.
In mice with high-fat diets, two areas of the brain, the hypothalamus, which helps to control whole body metabolism, and the nucleus accumbens, important in mood and behaviour, becomes insulin resistant.
“Your diet isn’t always necessarily just making your blood sugar higher or lower; it’s also changing a lot of signals coming from gut microbes and these signals make it all the way to the brain,” said C. Ronald Kahn, from the Joslin Diabetes Centre in the US.
“But all of these behaviours are reversed or improved when antibiotics that will change the gut microbiome were given with the high fat diet,” Kahn added.
In the study, published in the journal Molecular Psychiatry, the team identified the effect of the microbiome by transferring gut bacteria from experimental mice to germ-free mice which did not have any bacteria of their own.
The animals which received bacteria from mice on a high-fat diet began to show increased levels of activity associated with anxiety and obsessive behaviour.
However, those who got microbes from mice on a high-fat diet plus antibiotics did not, even though they did not receive the antibiotics themselves.
University of Pennsylvania researchers say that for the first time they have linked social media use to increases in depression and loneliness.
The idea that social media is anything but social when it comes to mental health has been talked about for years, but not many studies have managed to actually link the two.
To do that, Penn researchers, led by psychologist Melissa Hunt, designed a study that focused on Facebook, Snapchat and Instagram.
The results were published in the November issue of the Journal of Social and Clinical Psychology.
How study worked
The study was conducted with 143 participants, who before they began, completed a mood survey and sent along photos of their battery screens, showing how often they were using their phones to access social media.
“We set out to do a much more comprehensive, rigorous study that was also more ecologically valid,” Hunt said. That term, ecologically valid, means that the research attempts to mimic real life.
The study divided the participants into two groups: The first group was allowed to maintain their normal social media habits. The other, the control group, was restricted to 10 minutes per day on each of the three platforms: Facebook, Snapchat and Instagram.
The restrictions were put in place for three weeks and then the participants returned and were tested for outcomes such as fear of missing out (FOMO), anxiety, depression and loneliness.
Results of study
The results showed a very clear link between social media use and increased levels of depression and loneliness.
“Using less social media than you normally would leads to significant decreases in both depression and loneliness,” Hunt said. “These effects are particularly pronounced for folks who were more depressed when they came into the study.”
She calls her findings the “grand irony” of social media.
What is it about social media that’s just so depressing?
Hunt says that it’s two major things. The first is that social media invites what Hunt calls “downward social comparison.” When you’re online, it can sometimes seem that “everyone else is cooler and having more fun and included in more things and you’re left out,” she said. And that’s just generally demoralizing.
The second factor is a bit more nuanced.
“Time is a zero-sum game,” Hunt told VOA. “Every minute you spend online is a minute you are not doing your work or not meeting a friend for dinner or having a deep conversation with your roommate.”
And these real life activities are the ones that can bolster self-esteem and self worth, Hunt said.
What to learn
So what’s the takeaway?
People are on their devices, and that’s not going to change, she said. But as in life, a bit of moderation goes a long way.
“In general, I would say, put your phone down and be with the people in your life,” she added.
Hunt pointed out a few caveats to the study. First, it was done exclusively with 18- to 22-year-olds, and it is unclear if the depressing effects of social media will cross generational lines to older or younger people, Hunt said. But she expects her results should generalize at least for people through the age of 30.
Hunt says she is now beginning a study to gauge the emotional impact of dating apps. (VOA)