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The Connection Between Candida Overgrowth and Mental Health

While this may sound a little unsettling, the most common fungi taking up residence in our gut is Candida albicans. Candida albicans lives in co-existence with our gut microbiome bacteria. It can also be found in other mucosal parts of the body, such as the mouth (think thrush) and vagina, as well as in the bloodstream, where it can cause serious life-threatening infections. It's important to know that Candida overgrowth is not an infection. Unique to Candida, it can morph into different forms including a yeast form that is oval shape and a hyphae form that looks like a stick. I will talk about this more in the section on risk factors.


Candida overgrowth

Colonization occurs when the yeast grows in larger numbers where it doesn't cause an infection. Among healthy adults, 30-70% have colonization of Candida species. Because of the lack of specific symptoms associated with Candida overgrowth, it can be difficult to diagnose colonization or overgrowth. Like most things in life, Candida is not all bad - some amounts in our microbiome seem to have an important role in healthy gut microbiome function.


To understand how Candida Albicans overgrowth in the GI system affects mental health, we need to keep in mind that the gut and brain are closely connected.



Gut-Brain Connection

There are several ways our gut and brain are connected. Most of the serotonin we produce is made in the gut. The GI tract is a major site for immune activity; Inflammation from issues in the gut can cross the blood-brain-barrier and contribute to neuroinflammation in the brain, potentially manifesting as various psychiatric symptoms and/or cognitive symptoms.


Additionally, the gut lining acts as a barrier that prevents harmful substances from entering the bloodstream. When this barrier is compromised, a condition often referred to as "leaky gut," toxins and pathogens can enter the circulation, triggering an immune response that may also contribute to neuroinflammation and subsequently to psychiatric symptoms. Therefore, it's useful to consider the gastrointestinal symptoms in patients presenting for psychiatric assessment.



Symptoms Associated with Candida Overgrowth

There is emerging research that an overgrowth of fungi in the small intestine of non-immunocompromised individuals may cause unexplained GI symptoms in up to 25% of those living with chronic GI symptoms.


The most common gastrointestinal symptoms associated with Candida overgrowth include:

  • Belching

  • Bloating

  • Indigestion

  • Nausea

  • Diarrhea

  • Gas


Other non-gastrointestinal symptoms that are seen in individuals with Candida overgrowth include:

  • Fatigue

  • Poor concentration

  • Anxiety

  • Mood swings, depression

  • Anal itching

  • Strong cravings for sweets, carbohydrates



Factors that Increase Risk of Candida Overgrowth

What makes someone susceptible to Candida overgrowth? It's thought that both environmental and genetic factors can contribute, including:

  • Antibiotic use

  • Underlying inflammation (which can have many different causes - see weakened immune system)

  • High carbohydrate intake, which causes Candida to switch from the yeast to hyphae form which can penetrate tissues and negatively impact the immune system

  • Obesity

  • Diabetes (Type 1 or 2)

  • Weakened immune system - high and chronic stress, use of steroid medications, infections, mycotoxin exposure

  • Hormone fluctuations (pregnancy, post-partum, menopause, birth control pills)

  • Female individuals, possibly because of hormone fluctuations



Mental Health and Candida Overgrowth

Case studies and clinical experience illuminate the impact of assessing for and treating Candida overgrowth can positively have on mental health symptoms. Considering the close connection between the gut and brain, it makes sense that due to Candida's potential to increase gut permeability that mental health symptoms can be associated. Studies indicate that specific mental health conditions, such as depression, autism, schizophrenia, and ADHD may be connected to Candida overgrowth.


Assessing for and adequately treating Candida overgrowth through an integrative medicine approach that typically includes lifestyle changes and antifungal treatments, can be a very helpful tool for improving both physical and mental health symptoms in patients.


 

A kind reminder: This blog post is designed as a general guide. This is not a substitute for personalized medical advice, nor is a patient-physician relationship established in this blog post.



Sources:

Enaud R, Vandenborght L-E, Coron N, Bazin T, Prevel R, Schaeverbeke T, Berger P, Fayon M, Lamireau T, Delhaes L. The Mycobiome: A Neglected Component in the Microbiota-Gut-Brain Axis. Microorganisms. 2018; 6(1):22. https://www.mdpi.com/2076-2607/6/1/22


Erdogan, A., Rao, S.S.C. Small Intestinal Fungal Overgrowth. Curr Gastroenterol Rep 17, 16 (2015). https://doi.org/10.1007/s11894-015-0436-2. https://link.springer.com/article/10.1007/s11894-015-0436-2?TB_iframe=true#citeas


Harriot, MM. Importance of Candida–bacterial polymicrobial biofilms in disease. Trends in Microbiology. 2011. https://www.sciencedirect.com/science/article/abs/pii/S0966842X11001417

Herman A, Herman AP. Could Candida Overgrowth Be Involved in the Pathophysiology of Autism? Journal of Clinical Medicine. 2022; 11(2):442. https://www.mdpi.com/2077-0383/11/2/442


Musumeci, S et al. The human gut mycobiome and the specific role of Candida albicans: where do we stand, as clinicians?. Clinical Microbiology and Infection. 2022. https://www.sciencedirect.com/science/article/pii/S1198743X21004298#section-cited-by


Pérez JC. The interplay between gut bacteria and the yeast Candida albicans. Gut Microbes. 2021 Jan-Dec;13(1):1979877. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8489915/


Rucklidge JJ. Could yeast infections impair recovery from mental illness? A case study using micronutrients and olive leaf extract for the treatment of ADHD and depression. Adv Mind Body Med. 2013 Summer;27(3):14-8. PMID: 23784606. https://pubmed.ncbi.nlm.nih.gov/23784606/


Wang, L.-J., Li, S.-C., Yeh, Y.-M., Lee, S.-Y., Kuo, H.-C. and Yang, C.-Y. (2023), Gut mycobiome dysbiosis and its impact on intestinal permeability in attention-deficit/hyperactivity disorder. J Child Psychol Psychiatr, 64: 1280-1291. https://doi.org/10.1111/jcpp.13779





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