"What Your Teeth Are Telling You About the Health of Your Brain" (Part III of IV) by Megan Barnett

In my last post I focused on the connection between dental health and brain function, I explored how deficiencies in Vitamins B6 and D3 can cause adverse symptoms in your mouth as well as lead to mental health and cognitive impairment. If you are experiencing symptoms of oral diseases, mental health imbalance or cognitive decline, this post will shed some light on two more evidence-based methods to improve outcomes within your brain and mouth.

Green Tea
While no one is deficient in green tea, per say, green tea has known benefits to the brain as well as the teeth. Green tea polyphenol, epigallocatechin gallate, decreases the acid production of oral bacteria, S. Mutans leading to less acid production and a lower risk of cavity formation.1  L-theanine is an amino acid found in green tea which has been shown to reduce anxiety while improving alertness and calm blood pressure spikes that occur as a result of stress. L-theanine is also thought to reduce risk of stroke and cognitive decline.2  A 2014 study in Psycopharmacology found that green tea extract enhanced parieto-frontal connectivity during working memory processing and suggests that there may be promise in improving outcomes in cognitive disorders such as dementia.3


Probiotics are a variety of bacterial strains that have healthy or beneficial effects within our body. Most bacteria and other microorganisms that make up our unique microbiome are found in the colon but there are bacteria that reside throughout other areas of the digestive system and body as well. Probiotic sales are on the rise because they help our body rebalance beneficial bacteria against toxic or harmful bacteria, fungi, and viruses after assaults such as antibiotics, parasites, pesticides, GI virus, and poor Western diet wipe out healthy species. In Western cultures, which support a highly processed diet riddled with pesticide and antibiotic use, this type of assault on our microbiome is almost constant which can result in an imbalanced microbiome and a multitude of unwanted symptoms. Bacteria, whether it is helpful or harmful, compete for space and resources throughout our body. Probiotics are beneficial in part, because they compete for space leaving less real estate for the unhealthy bacteria.

Research shows that certain probiotic strains including L. rhamnosus GG and B. Lactis Bb12 (found in brands such as Culterelle and Standard Process Prosymbiotic), can be effective in decreasing cavity incidence.4  Remember from part I of this series, the bacteria S. Mutans, found in the mouth, can cause cavities due to the excretion of acidic waste left on the teeth. It would make sense that by minimizing the colony of S. Mutans in the mouth, you may be able to minimize cavity formation. In a 2001 study of almost 600 children aged 1 to 6 years old, Lactobacillus GG was added to the milk of a randomly assigned group , while the control group drank milk without probiotics. After 7 months, incidence of cavities was 49% lower in those drinking milk containing probiotics likely due to the suppression of S. Mutans growth.1

Probiotics effect more than your mouth. A growing body of research is focusing on the relationship between the microbiome and the function of the brain. Healthy bacteria in the colon produce neurotransmitters such as serotonin as well as butyrate, a short chain fatty acid known to benefit cognition and neurological disorders. Maintaining a healthy microbiome with a healthy diet high in plant fiber as well as probiotics supports the production of compounds that contribute to increased cognition and better mental health
.5  A 2015 study in the journal Neuroscience found that they were able to alter the cognitive function of rats by feeding them either high fat or high sucrose diets, which affects microbiome balance because diets high in fat and sugar promote unhealthy bacterial growth. Both diets had negative effects on cognition in comparison to a healthy balanced diet.6  Both Bifidobacterium longum R0175 and L. helveticus R0052 (found in brands such as Xymogen Probio Defense) have been found to have a positive effects on anxiety, stress and depression.7

It is important to know that all probiotics are not created equally and that they are strain specific, meaning that every species and strain do not work for every condition. Look for probiotic brands that contain at least 1 billion live cultures per serving and that label not only the species, but also the strain as noted above. Eating a diet that includes fermented foods such as miso, kimchi, sauerkraut, etc. can also improve gut flora. If you are trying to treat a specific condition, it is best to seek the help of a trained professional.


Stay tuned for the final article in this series (Part IV)!

And if you missed it, make sure to catch Part I and Part II of the Series.

  1. Gaby, A. (Ed.). (2011). Nutritional medicine. Concord, NH: Fritz Perlberg Publishing.
  2. Sanford, A. (2016). Brain Benefits of L-Theanine. Life Extension, 33-37.
  3. Schmidt, A., Hammann, F., Wölnerhanssen, B., Meyer-Gerspach, A., Drewe, J., Beglinger, C., & Borgwardt, S. (2014). Green tea extract enhances parieto-frontal connectivity during working memory processing. Psychopharmacology, 231(19), 3879-3888.
  4. Ulbricht, C., Budiman, T., Chao, W., Tanguay-Colucci, S., Conquer, J., Costa, D., & ... Zhou, S. (2011). Probiotics ( Bifidobacterium, Lactobacillus, and Saccharomyces boulardii): An Evidence-Based Systematic Review by the Natural Standard Research Collaboration. Alternative & Complementary Therapies, 17(6), 334. doi:10.1089/act.2011.17601
  5. Bourassa, M. W., Alim, I., Bultman, S. J., & Ratan, R. R. (2016). Review article: Butyrate, neuroepigenetics and the gut microbiome: Can a high fiber diet improve brain health?. Neuroscience Letters, 625(Epigenetics and Disorders of the Nervous System), 56-63. doi:10.1016/j.neulet.2016.02.009
  6. Magnusson, K., Hauck, L., Jeffrey, B., Elias, V., Humphrey, A., Nath, R., & ... Bermudez, L. (2015). Relationships between diet-related changes in the gut microbiome and cognitive flexibility. Neuroscience, 300128-140. doi:10.1016/j.neuroscience.2015.05.016
  7. Messaoudi, M., Lalonde, R., Violle, N., Javelot, H., Desor, D., Nejdi, A., & ... Cazaubiel, J. (2011). Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects. The British Journal Of Nutrition, 105(5), 755-764. doi:10.1017/S0007114510004319



Megan Barnett works as an educator and coach facilitating the incorporation of healthy behaviors into her clients’ daily lives using nutrition, lifestyle, and mindful eating to promote overall wellness and optimal functioning. Megan has a BS in Dietetics from Kansas State University, is a certified yoga instructor and is currently completing a Master's degree in Nutrition and Functional Medicine at University of Western States in Portland, Oregon.  www.pepnutritioncoach.com