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Are Probiotics the New Prozac?

August 21, 2013

By Dr. Mercola

While many think of their brain as the organ in charge of their mental health, your gut may actually play a far more significant role.

The big picture many of us understand is one of a microbial world that we just happen to be living in. Our actions interfere with these microbes, and they in turn respond having more effects to our individual health as well as the entire environment.

There is some truth to the old expression, having ‘dirt for brains’.  The microbes in our soil, on our plants, in our stomachs are all a result of our actions.  Antibiotics, herbicides, vaccines, and pesticides, and the tens of thousands of synthetic chemicals we’ve created all have impacts and result in reactions from these microbes.

Mounting research indicates that problems in your gut can directly impact your mental health, leading to issues like anxiety and depression.

The gut-brain connection is well-recognized as a basic tenet of physiology and medicine, so this isn’t all that surprising, even though it’s often overlooked. There’s also a wealth of evidence showing intestinal involvement in a variety of neurological diseases.

With this in mind, it should also be crystal clear that nourishing your gut flora is extremely important, because in a very real sense you have two brains, one inside your skull and one in your gut, and each needs its own vital nourishment. A recent article1 titled “Are Probiotics the New Prozac?” reviews some of the most recent supporting evidence.

Probiotics Alter Brain Function, Study Finds

The featured proof-of-concept study, conducted by researchers at UCLA, found that probiotics (beneficial bacteria) actually altered participants’ brain function. The study2 enlisted 36 women between the ages of 18 and 55 who were divided into three groups:

  • The treatment group ate yogurt containing several probiotics thought to have a beneficial impact on intestinal health, twice a day for one month
  • Another group ate a “sham” product that looked and tasted like the yogurt but contained no probiotics
  • Control group ate no product at all

Before and after the four-week study, participants underwent functional magnetic resonance imaging (fMRI) scans, both while in a state of rest, and in response to an “emotion-recognition task.”

For the latter, the women were shown a series of pictures of people with angry or frightened faces, which they had to match to other faces showing the same emotions.

“This task, designed to measure the engagement of affective and cognitive brain regions in response to a visual stimulus, was chosen because previous research in animals had linked changes in gut flora to changes in affective behaviors,” the researchers explained.

Compared to the controls, the women who consumed probiotic yogurt had decreased activity in two brain regions that control central processing of emotion and sensation:

  • The insular cortex (insula), which plays a role in functions typically linked to emotion (including perception, motor control, self-awareness, cognitive functioning, and interpersonal experience) and the regulation of your body’s homeostasis, and
  • The somatosensory cortex, which plays a role in your body’s ability to interpret a wide variety of sensations

During the resting brain scan, the treatment group also showed greater connectivity between a region known as the ‘periaqueductal grey’ and areas of the prefrontal cortex associated with cognition. In contrast, the control group showed greater connectivity of the periaqueductal grey to emotion- and sensation-related regions.

The fact that this study showed any improvement at all is remarkable, considering they used commercial yogurt preparations that are notoriously unhealthy; loaded with artificial sweeteners, colors, flavorings, and sugar. Most importantly, the vast majority of commercial yogurts have clinically insignificant levels of beneficial bacteria. Clearly, you would be far better off making your own yogurt from raw milk—especially if you’re seeking to address depression through dietary interventions.

Yes, Your Diet Affects Your Mood and Mental Health

According to lead author Dr. Kirsten Tillisch:3, 4

“Time and time again, we hear from patients that they never felt depressed or anxious until they started experiencing problems with their gut. Our study shows that the gut–brain connection is a two-way street… ‘When we consider the implications of this work, the old sayings ‘you are what you eat’ and ‘gut feelings’ take on new meaning.’”

The implications are particularly significant in our current era of rampant depression and emotional “malaise.” And as stated in the featured article, the drug treatments available today are no better than they were 50 years ago. Clearly, we need a new approach, and diet is an obvious place to start.

Previous studies have confirmed that what you eat can alter the composition of your gut flora. Specifically, eating a high-vegetable, fiber-based diet produces a profoundly different composition of microbiota than a more typical Western diet high in carbs and processed fats.

The featured research tells us that the composition of your gut flora not only affects your physical health, but also has a significant impact on your brain function and mental state. Previous research has also shown that certain probiotics can help alleviate anxiety:

  • The Journal of Neurogastroenterology and Motility5 reported the probiotic known as Bifidobacterium longum NCC3001 normalized anxiety-like behavior in mice with infectious colitis by modulating the vagal pathways within the gut-brain.
  • Other research6 found that the probiotic Lactobacillus rhamnosus had a marked effect on GABA levels—an inhibitory neurotransmitter that is significantly involved in regulating many physiological and psychological processes—in certain brain regions and lowered the stress-induced hormone corticosterone, resulting in reduced anxiety- and depression-related behavior. It is likely other lactobacillus species also provide this benefit, but this was the only one that was tested.

It’s important to realize that you have neurons both in your brain and your gut — including neurons that produce neurotransmitters like serotonin. In fact, the greatest concentration of serotonin, which is involved in mood control, depression and aggression, is found in your intestines, not your brain! Perhaps this is one reason why antidepressants, which raise serotonin levels in your brain, are often ineffective in treating depression, whereas proper dietary changes often help…

Read more: http://articles.mercola.com/sites/articles/archive/2013/07/25/probiotics-new-prozac.aspx?e_cid=20130725_DNL_art_1&utm_source=dnl&utm_medium=email&utm_content=art1&utm_campaign=20130725

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