Probiotics Shown to Alleviate Anxiety

In a new meta-analysis of ten studies, probiotics are proving useful in decreasing symptoms of anxiety. 


Our stomach is a fascinating place. With all the advancements being made in neuroscience, the complexities of digestion have not been well understood, the dark matter of our body’s galaxy. That is changing, quickly. 

Part of the challenge is complexity: there are 100,000 times more microbes in your gut than humans on this planet, writes Emeran Mayer in The Mind-Gut Connection. There are also more immune cells inside of our stomachs than in blood and bone marrow, which makes what we put into our mouths so important. Our diets might affect our brains more than the other way around. As Mayer puts it,

Your gut microbes are in a prime position to influence your emotions, by generating and modulating signals the gut sends back to the brain. 

Humans are collectively experiencing increased rates of anxiety, which is now the planet’s most pervasive psychological disorder. Increased stress has numerous destructive tendencies in our guts, including the alteration of contractions, transit rates between our stomach and large intestine, and blood flow. When that blood is transporting extra cortisol due to an increase in our corticotropin-releasing factor (CRF), the result is increased storage of visceral fat, decreased function of our immune system, and, of course, anxiety. 

While there are a number of means for altering your gut environment—a healthier diet with less sugar; stress-reducing techniques like meditation; regular exercise; therapy—one of the most prominent is the intake of probiotics, as new research published in Neuropsychiatry (London) shows.

Our guts are filled with microbes. I remember my high school biology teacher trying to gross us out by informing us that if she were to zap us so that only living microorganisms would remain, a few pounds would end up next to each of our desks. Turns our these critters are necessary for survival; how we treat them affects how they treat us. 

Probiotics are, in the words of the World Health Organization, “live micro-organisms which, when administered in adequate amounts, confer a health benefit on the host.” In 2010 the organization began developing guidelines for probiotics in food, which is tricky for a number of reasons. First off, each host has a different gut environment; what works for you might not work for me. Second, dosage amounts are also relative for each host. Constructing widespread guidelines on what needs to be individualized prescriptions is challenging. 

Thirdly, the FDA is notoriously inefficient when screening health claims. There’s a world of difference between refrigerated and room temperature probiotics, one that extends well beyond price. Yet this barely-regulated industry is difficult to navigate. Stated benefits exceed actual benefits, as often happens with medicine masquerading as nutritional supplements. 

The research team above, led by Ruixue Huang at the Xiangya School of Public Health in Hunan, China, searched seven academic databases and chose ten studies that showed probiotics’ efficacy in reducing anxiety. Importantly, the team recognizes crosstalk between gut and brain:

The gut-brain relationship is bidirectional, meaning that changes in microbial flora can affect behaviour, and behavioural changes can affect the gut flora.

The team had been searching for a meta-analysis on probiotics and anxiety disorders, which they were unable to find. Their requirements included studies on human subjects with anxiety disorders, a variety of probiotic sources (fermented yogurt; powders; oil suspensions; capsules), and studies from unique test groups, to avoid overlap. They did not include studies on mice and rats, case reports, or incomplete data. 

Huang’s team collected research from Japan, Spain, Ireland, Iran, the UK, Sweden, France, and Canada, all of which showed beneficial effects from a variety of probiotics, including popular and readily available strains such as Lactobacillus acidophilus and Lactobacillus casei. A total of 660 human subjects were included in their final results: 

Meta-analysis results indicated that probiotics significantly decreased anxiety compared to controls. These results are consistent with some previous studies showing that probiotics on anxiety are effective.

As Mayer concludes in his book, however, there is no “one-size fits all recommendation” for probiotics. He continues, 

We cannot expect that any simple intervention by itself, such as a particular diet, will optimize your gut microbiome, while not paying attention to all the other factors that influence gut microbial function, like the influence of unhealthy gut reactions associated with stress, anger, and anxiety at the same time. 

So while probiotics might not cure your anxiety in one shot, they can play an important role in the process. Understanding strains and dosage is an exciting field of research that is certain to yield critical advancements in the near future. 

--

Derek is the author of Whole Motion: Training Your Brain and Body For Optimal Health. Based in Los Angeles, he is working on a new book about spiritual consumerism. Stay in touch on Facebook and Twitter.

LinkedIn meets Tinder in this mindful networking app

Swipe right to make the connections that could change your career.

Getty Images
Sponsored
Swipe right. Match. Meet over coffee or set up a call.

No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.

Keep reading Show less

Think you’re bad at math? You may suffer from ‘math trauma’

Even some teachers suffer from anxiety about math.

Image credit: Getty Images
Mind & Brain

I teach people how to teach math, and I've been working in this field for 30 years. Across those decades, I've met many people who suffer from varying degrees of math trauma – a form of debilitating mental shutdown when it comes to doing mathematics.

Keep reading Show less

A world map of Virgin Mary apparitions

She met mere mortals with and without the Vatican's approval.

Strange Maps
  • For centuries, the Virgin Mary has appeared to the faithful, requesting devotion and promising comfort.
  • These maps show the geography of Marian apparitions – the handful approved by the Vatican, and many others.
  • Historically, Europe is where most apparitions have been reported, but the U.S. is pretty fertile ground too.
Keep reading Show less

How KGB founder Iron Felix justified terror and mass executions

The legacy of Felix Dzerzhinsky, who led Soviet secret police in the "Red Terror," still confounds Russia.

Getty Images
Politics & Current Affairs
  • Felix Dzerzhinsky led the Cheka, Soviet Union's first secret police.
  • The Cheka was infamous for executing thousands during the Red Terror of 1918.
  • The Cheka later became the KGB, the spy organization where Russia's President Putin served for years.
Keep reading Show less