Can Probiotics Help Your Brain, Too?

Wednesday Aug 7 | BY |
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New research discovered that probiotics, like those found in yogurt,
may help relieve stress and anxiety.

A recent study has provided more evidence to support the old adage, “you are what you eat.”

While most of us know that probiotics are friendly bacteria that help us enjoy a healthy digestive system, researchers have now found that these same bacteria in the gut may affect brain function, as well.

We’re not talking about increasing your intelligence here—though that may be possible, too—but making changes in the emotional area of the brain. Would you like to experience less stress and anxiety? It could be that you would feel happier if you supplemented your diet with probiotics.

What are Probiotics?

Considered one of the “new” health miracles, probiotics are friendly bacteria that naturally live in the digestive system and provide health benefits. Their presence in the colon helps keep “bad” bacteria from proliferating and causing problems. They also help stimulate the body’s own immune responses, essentially helping to boost the immune system. (Dr. Williams writes more about gut bacteria in a former post.)

So far, scientists have found that probiotics help maintain healthy bowel activity, synthesize certain nutrients, help in nutrient and mineral absorption, and stimulate our defenses. They may also help prevent colon cancer, reduce cholesterol levels, and even prevent dental caries.

New Study Gives Women Yogurt

For this new study, researchers split 36 healthy women, ages 18 to 50 with no gastrointestinal or psychiatric symptoms into three groups:

  1. The first received a fermented milk product with a probiotic (yogurt with live probiotic cultures)
  2. The second received a nonfermented milk product (yogurt without live cultures)
  3. The third received nothing

The groups that received the milk products consumed them twice daily for four weeks, 125 grams at each serving. The yogurt with live cultures included probiotics B. lactis CNCM I-2494, L. bulgaricus, S.Thermophilus, and L. lactis.

The women also had MRIs taken before and after the four-week period, to measure brain response to an emotional activity and to study resting brain activity.

Study Results Show Multiple Effects

To measure the women’s emotional responses, researchers showed them pictures of angry or frightened faces and had them match them to other faces with the same expressions. While they were performing this task, scientists measured their response to the visual stimulus.

They found that during this task, those who had consumed the probiotic yogurt experienced less activity in both the insula and the somatosensory cortex, which processes internal body sensation.

These women also had decreased activity in the emotion-, cognition-, and sensory-related areas of the brain, compared to the women in the other two groups. In addition, in the resting state, the women consuming probiotics showed more connectivity between the brainstem region called the “periaqueductal grey” and other areas of the prefrontal cortex responsible for cognition.

What does all this mean?

Interpreting the Results

A way to summarize the findings is to say that women consuming the probiotic yogurt showed lower levels of activity in areas of the brain associated with emotion and pain, and higher levels of activity in areas associated with decision making. The researchers noted that this may suggest that probiotics could have health benefits such as relieving anxiety, stress, and other mood symptoms over time.

“Our study shows that the gut-brain connection is a two-way street,” said Dr. Kirsten Tillisch of UCLA’s School of Medicine, who led the study.

This isn’t the first study to indicate that probiotics may affect the brain—though it is the first human study. Previous animal studies have also shown that altering gut bacteria can produce more anxious or bold characteristics. A 2011 study found that probiotics seemed to reduce physiological stress responses of mice, and also lowered their levels of stress hormone, compared with mice not fed probiotics.

While the scientists admit that more research needs to be done, the implications are exciting. Maybe the next time you’re feeling a little low, you should try a cupful of yogurt, kefir, miso, tempeh, or sauerkraut!

Do you find that probiotics help your mood? Please share your thoughts.

* * *

Melanie Hall, “Eating probiotic yoghurt relieves anxiety, study says,” Telegraph, May 30, 2013,

Kirsten Tillisch, et al., “Consumption of Fermented Milk Product with Probiotic Modulates Brain Activity,” Gastroenterology, 144(7):1394-1401.e4, June 2013,

Rachel Reilly, “Could eating yoghurt help treat depression?” Daily Mail, May 29, 2013,

“Dietary Changes to Gut Bacteria Can Affect Brain Functioning, Study Suggests,” Huffington Post, June 17, 2013,

Colleen M. Story

Colleen M. Story

Colleen M. Story, a northwest-based writer, editor, and ghostwriter, has been creating non-fiction materials for individuals, corporations, and commercial magazines for over 17 years. She specializes in the health and wellness field, where she writes and ghostwrites books, e-books, blogs, magazine articles, and more.

Colleen is the founder of Writing and Wellness. Her fantasy novel, “Rise of the Sidenah,” was released with Jupiter Gardens Press in September 2015. Her literary novel, “Loreena’s Gift,” is forthcoming in spring 2016 from Dzanc Books. She lives in Idaho.


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  1. David Morgan says:

    Thanks Colleen for sharing this post. Probiotics are good bacterias for our health. Probiotic bacterias are mainly reduced the diarrhea. I have no ideas that they are good for our brain also. Thanks again.

  2. John Russell says:

    Do probiotics have the capacity for dealing with mental disorders or emotional problems brought about by physilogical deficits? By the way, this was actually covered in the book “Cultured”. Fermented foods can actually affect your mood.

  3. Frank says:

    I haven’t had enough long-term experience with probiotics yet to determine whether they help my mood, but I’m giving it a shot. I’ve been looking into probiotics a bunch recently to decide which to buy and read this post on the bulletproof exec about why you want to avoid certain strains of probiotic that are histamine-producing:
    After reading it I found these probiotics which have 2 of the histamine degrading strains (Bifidobacterium longum, Lactobacillus plantarum) and none of the histamine producing strains, so if that’s a concern of yours too, these should work well! They come in 30bn and 100bn versions for $35 and $63, respectively:
    Xymogen ProbioMax DF – 100 Billion CFU Probiotic – 30 vcaps
    XYMOGEN ProbioMax Daily DF 30 billion CFU probiotic 30 vege caps

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