Saturday November 17, 2018

Microbes May Be Stirring Up Anxiety And Depression In Obese People

To test the theory, Kahn and colleagues fed mice a high-fat diet and studied their behavior as the animals became obese

0
//
Microbes May Be Stirring Up Anxiety And Depression In Obese People
Microbes May Be Stirring Up Anxiety And Depression In Obese People, Pixabay
Republish
Reprint

Microbes may be helping stir up anxiety and depression in obese people, if results from a new mouse study hold true in humans.

The authors link the effects to how the brain responds to insulin, the hormone that regulates sugar levels in the blood.

The research raises questions about whether changing gut microbes, or changing diet, could help treat these conditions.

Mood, microbes and metabolism

Obesity triggers changes in metabolism — for example, making liver, muscle, fat and other tissues less responsive to insulin. Left untreated, these changes can lead to diabetes.

Obese people also have higher rates of anxiety and depression.

“One could say, ‘Maybe that’s just because they’re obese,’ ” said Harvard Medical School diabetes researcher Ronald Kahn, “but others could say, ‘Maybe there’s a metabolic link.’ ”

“And we asked the question, ‘Maybe the metabolic link is at least partly fueled by the microbiome,’ ” the community of microbes living in a person’s gut, he added.

Those microbes change with diet, and Kahn said different microbes might respond differently to the foods we eat.

To test the theory, Kahn and colleagues fed mice a high-fat diet and studied their behavior as the animals became obese.

They used common tests to gauge anxious and depressed behavior in rodents — for example, how much time the animals spent hiding in a dark box versus exploring a brightly lit area. The more anxious the mouse, the less time it will spend in the light.

Obese mice spent about 25 percent less time in the light than animals on a normal diet, and they scored higher on the other anxiety and depression tests, too.

obesity
obesity, Pixabay

Return to normal

But those differences disappeared when obese mice were given antibiotics, even though their weight didn’t change much.

“That really says there’s probably something about the microbiome,” Kahn said.

The researchers then tested how the animals’ microbiomes affected mice raised in a sterile environment with no microbes of their own.

Bacteria from obese rodents made these germ-free mice more anxious than microbes from normal mice.

But when germ-free mice got microbes from obese animals that had been given antibiotics, they behaved like normal mice.

To see what parts of the brain might be responsible for the effects, the researchers focused on two regions involved in metabolism and responses to rewards. They found these regions were less responsive to insulin in the obese mice compared with normal-weight animals.

Again, antibiotics returned those responses to normal.

The research appears in the journal Molecular Psychiatry.

“It was actually quite a surprise,” Kahn said. “Even though we had seen some effects on metabolism in the rest of the body, I was very surprised how dramatic and how clear the effects were also on the brain and on behavior.”

Into the unknown

That doesn’t mean antibiotics are the cure for depression, Kahn warned. The drugs kill good and bad microbes indiscriminately, and taking the medication unnecessarily can contribute to the rising threat of antibiotic resistance.

Also, what happens in mice does not necessarily happen in humans, he added, or it may happen for only some people. So far, there is not much evidence that probiotics help anxious people.

scale
scale, Pixabay

“The difficulty is, both of these things — depression and obesity — are complicated things that have multiple, multiple factors influencing them,” said mental health researcher Gregory Simon at Kaiser Permanente Washington Health Research Institute, who was not part of the study.

Microbes are likely just one factor, along with environment, genetics, social influences and more, Simon added.

But Kahn said his group’s research raised interesting questions about how food affects our behavior.

“I think now we can get some idea that there are a lot of things that are being metabolized by gut bacteria that could affect brain function,” he said.

And he said there might be ways to change brain function by changing those bacteria, by eating helpful microbes or by eating foods that sustain them.

Also read: Two New Ways To Prevent Cholera: Microbes Fighting Microbes

He and his colleagues are working to figure out exactly which of the hundreds of species of gut bacteria are responsible. At the moment, it’s a mystery. (VOA)

Click here for reuse options!
Copyright 2018 NewsGram

Next Story

Loneliness And Depression Can Be Linked to Social Media: Study

It is unclear if the depressing effects of social media will cross generational lines to older or younger people

0
Social Media,
This photo taken March 22, 2018, shows apps for WhatsApp, Facebook, Instagram and other social networks on a smartphone. VOA

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.

Social media. Offensive Speech
An iPhone with Twitter, Facebook and other apps, May 21, 2013. U.S. internet companies are taking a harder look at their policies that have promoted free expression around the world.. VOA

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.

Social Media
Chiara Valenzano, right, photographs her food as she has lunch with her friend Giulia Terranova at the ‘This is not a Sushi bar’ restaurant, in Milan, Italy, Oct. 16, 2018. At the restaurant, payment can be made according to the number of Instagram followers one has. VOA

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.

Social Media
The study was conducted with 143 participants, who before they began, completed a mood survey Pixabay

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?

social media
A girl uses her mobile phone in Jakarta, Indonesia, July 5, 2017. A researcher in Britain says her findings suggest young girls who are more active on social media have lower levels of well-being in their teens. VOA

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.

Also Read: Childhood Violence May Spur Puberty, Depression: Study

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)