Choosing the Right Probiotics for Healing the Mood and Mind

by Dr. Susan Tanner, MD

In the integrative medicine world, we practitioners are receiving many articles these days on the importance of the gut microbiome.  The term “microbiome” has been used much more frequently in recent years as research delves more into the vast importance of the inner lining of the small intestine, the gut, and its important impact on multiple functions in the body. For years the universal impression was that the gut was only responsible for digesting foods, extracting and absorbing nutrients, and little else. The gut was thought of more as a conduit or tube that carried the products of digestion through the system.  Of course, the gut does do that, but its structure and function are truly quite complex and can positively or negatively influence almost every organ and tissue in the body. Today, I wish to turn our focus to the ways in which the health of a person’s gut microbiome can directly affect their mental health or mood.

The Microbiome

The term “microbiome” comes from the Greek word micros, meaning small, and bios, meaning life, but one must take it further to explain the community in which these small lives that comprise the gut (bacteria, fungi, plasmids, etc) interact.  The microbiome was defined more precisely in 1988 by Whipps et al. as “a characteristic microbial community occupying a reasonably well-defined habitat which has distinct physio-chemical properties. The term thus not only refers to the microorganisms involved but also encompasses their theatre of activity.”   And, it is in this theater of collective activity that the microbiome’s impacts on mental health come to light. For example, you have very likely heard the term “gut feeling”, which was coined decades ago.  But, what does this even mean?  In analyzing the function and structure of the gut, some experts have called the gut the “second brain” as it was discovered that neurotransmitters, the chemicals responsible for thought processes, mood, focus, and memory are largely produced in the gut lining and have a direct impact on brain function and mood.  Furthermore, these neurotransmitters can become inflammatory in nature, when an altered microbiome creates imbalances in the gut and cause issues with brain function. In fact, a growing body of research seems to confirm that as the gut suffers and becomes discombobulated with “bad actors”, so does the brain, becoming out of whack and often more confused and inflamed.

Mold and Mycotoxins’ Impact on the Gut

In discussions about mold-injured patients, the impacts on the gut and microbiome have been large and widespread–the on-guard nervous system slows digestion and the absorption of crucial nutrients, inhaled and swallowed mold spores create dysbiosis, fungal overgrowth, and infections, immune system dysregulation creates inflammation and/or immune compromise, the list goes on.  Additionally, the overgrowth of candida–prevalent with mold-exposed patients, has also been cited as the cause of brain fog, mood disorders, food cravings, and attention deficits. Many patients find that they feel and function much better by eliminating yeast overgrowth or candida to the extent possible and incorporating the right probiotics into the treatment protocol.  A big question, though, is how much of the cognitive improvement is actually from the elimination of candida (or greatly decreased levels, I don’t believe we can or should eliminate it in its entirety) or from the implementation of beneficial probiotic strains to reinoculate the gut lining to create a greater balance and happy “theatre of activity”?


If you read anything these days about probiotics, welcome to the world of confusion! There are hundreds of brands and the type and variety vary hugely. From reputable companies selling professional-grade supplements,  most probiotic products are good, some are better, and there are circumstances or health conditions in which one type might be chosen over another.  But, because the human microbiome is so complex, it is doubtful that its community can be replicated with a supplement. However, the use of probiotics can help establish a healthier immune lining which then can then assist the body in fostering the growth of these beneficial organisms in good balance. Shifting the diet to include foods called “prebiotics” is important as well. These prebiotic foods contain very specific fiber and growth-fostering products that help beneficial bacteria thrive, and include such things as Jerusalem artichokes, jicama, and other plant fibers, like inulin. There is also new information on polyphenols (micronutrients that naturally occur in plants) and their unique capacity to foster the growth of beneficial gut bacteria, which is another reason to try to eat a colorful diet, full of antioxidant-rich foods when trying to maintain a healthy body and mind.

Mood- and Mind-Enhancing Organisms

Research is now revealing members of the microbiome which have a specific and beneficial impact on mental health.   These organisms seem to enhance memory and help alleviate brain fog, depression, and lack of clarity, which may explain why simply eradicating or reducing candida did not resolve these symptoms in some cases. It appears as if some bacteria are actually needed in the gut for mood and mind to stay balanced, regulated, and healthy.

Lactobacillus plantarum DR7 is one heavily studied and researched organism that shows positive mood- and mind-enhancing properties.  Specific to brain health, L. Plantarum DR7 has been shown to support cognition and memory in both humans and animals and to help with the maintenance of brain function during the aging process. Clinical trials show that Lactobacillus plantarum DR7 enhances the serotonin pathways while simultaneously stabilizing the dopamine pathway. (Serotonin is the neurotransmitter associated with mood, calmness, and sleep, while dopamine is generally associated with activation, motivation, memory, and focus.) Patients in the study taking L planetarium DR7 experienced relief of stress and less nervous energy while also gaining greater mental clarity, and improved attention on tasks related to learning and memory. Additional benefits of supplementing with Lactobacillus plantarum DR7 included more normal bowel movements and better immune health due to the impacts on the activation of Natural Killer cells, which are the first lines of defense in the innate immune system. That is a lot of bang for the buck from one bacterial strain!

There are now tests available, GI Maps, which can analyze the microbiome of the gut for the array of bacteria present.  Testing may be a helpful thing to do in some cases, but my thinking is that you can do NO harm by adding a simple probiotic, like Lactobacillus plantarum DR7, to the daily regimen if any of the aforementioned mental symptoms are plaguing you!

It is still important to do all things possible to get the gut healthy, with clean air, nourishing foods, and basic good, broad-spectrum probiotics, but now that we know so much about Lactobacillus plantarum DR7, it may be worth adding to your regimen. One I like is called Microflora Mood and Mind Support.  It may require being on this for an 8-week period of time to notice overall beneficial impacts, but, as with most supplements, improvements are often gradual and you may not have a sudden, “BINGO I am better!” type of response.  After the 8-12 week period, it may or may not need to be continued long-term.  In a healing gut microbiome, once the terrain is well-seeded, we hope that this can continue to propagate on its own given the right environment.

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