Candida is one of a number of fungal residents of the human gut. An overgrowth and the progression towards the hyphal form of Candida is commonly associated with digestive symptoms and an activated immune system, classic signs of a Candida infection. Something is invading that needs to be dealt with. Today we will explore how Candida moves from a harmless commensal yeast to a harmful, gut wall damaging fungi.
How Does harmless Candida become a harmful Candida infection?
First off it is important to point out that Candida is a normal and healthy member of our gut ecosystem. Yes even Candida albicans (the most common Candida that misbehaves often). Candida can be found in the gastrointestinal tract, the skin, mouth and even the female reproductive tract as a normal and healthy part of the microbial balance. It is when it is given space to overgrow that this fungal species can become problematic (1).
One paper, published in 2016, summarised this thinking quite nicely.
‘C. albicans is a harmless commensal that exists in harmony with other members of the microbiota. However, disturbances to this delicate balance, resulting, for example, from variations in the local environment (pH shifts or nutritional changes), use of antibiotics, or alterations in the immune system (caused by an infection or immunosuppressant therapy), can enable C. albicans to rapidly proliferate and cause infection’Published in Microbes and Infection
When Candida is allowed to overgrow, and becomes a Candida infection it is associated with a range of issues (as seen in the image below) including:
- Skin infections
- Vaginal infections
- Wound infections
- Lung infections
- Blood infections
Here we are seeing a very common pattern emerge. Something that we have covered when dealing with a whole range of bacterial overgrowths (including Bilopila and Citrobacter infections). When commensal microbes are given space to grow many will. Then, what was once an insignificant member of a larger ecosystem in the gut becomes problematic.
Formation of Hyphae by a Candida Infection
Candida albicans can take a number of different forms (called polymorphic). These forms include a unicellular yeast, pseudohyphae and hyphae. The unicellular yeast form of Candida albicans is thought to be harmless and doesn’t cause any gut damage resulting in symptoms.
It is only when Candida albicans takes on the hyphal form that it becomes an issue.
This hyphal form is responsible for infecting the mucosal layer of the gut and damaging the cells that make up our gut wall. This hyphal form can actually force it’s way past the gut wall (think leaky gut and all the diseases associated with it) and into the body, resulting in blood infections (3).
But what drives Candida albicans to change from the harmless unicellular yeast into the more damaging hyphal form?
Keeping Candida in check
Again we come back to the microbial balancing act. Some bacteria in the gut help to keep the peace in a number of different ways.
Bifidobacteria is a prime example of this concept. Not only does it produce or liberate B vitamins, antioxidants and polyphenols, it also keeps the intestinal barrier intact and happy, tunes and regulates the immune system and blocks pathogens and pathobionts (such as Candida) from adhering to the gut mucosa by secreting antimicrobial peptides (bacteriocins) and decreasing the gut pH making it less favourable to the pathogens and pathobionts (4).
One paper even found that Lactobacilli kept Candida albicans from converting from the unicellular yeast into the hyphal form.
Finally, and possibly most importantly, the same paper found that the rock star short chain fatty acid butyrate also stopped the conversion from harmless Candida to a harmful Candida infection from happening!
Microbial Balance Wins Again
I am constantly amazed and awed by the gut ecosystem. Sometimes I feel as if we are given everything we need when we inherit an intact and healthy gut microbiome from mom when we are born.
The interplay between our beneficial bacteria that reside in our gut and the commensal turned pathobiont microbes is complex.
Obviously, when we talk about interactions between genera in an ecosystem it gets complex. We don’t have all of the pieces to the puzzle yet (maybe we never will).
With that disclaimer out of the way here is a basic break-down as I understand it.
Beneficial bacteria such as the members of the Bifidobacterium and Lactobacillus genera can compete for and keep in check particular less-friendly bacteria (and yeast) from dominating the ecosystem and causing issues.
At the same time, through the fermentation of undigested carbohydrates, they produce a variety of beneficial substances (mainly short chain fatty acids such as propionate, acetate as well as lactate) (6).
The three main short chain fatty acids are outlined in the table below
These by products from Bifidobacterum and Lactobacillus species in the gut can then go on to feed other beneficial bacteria (a term called cross-feeding) that produce the amazing short chain fatty acid butyrate. Many of the bacteria that produce butyrate can be seen in the image below. Keep an eye out for some key players including Faecalibacterium prausnitzii, Akkermansia muciniphila, Roseburia intestinalis and Eubacterium rectale.
An imbalanced (dysbiotic) Gut leads to a Candida Infection
When we take everything outlined above into account we can see that when the beneficial gut bugs aren’t present in significant numbers Candida is more apt to shift from a peaceful member of the gut to more of a pathogen-like (more like pathobiont) microbe.
The take home message here is that anything that disrupts, damages or disbalances the gut microbiota can lead to Candida overgrowths and infections.
‘A well-known risk factor for invasive candidiasis is the use of broad-spectrum antibiotics’ (8).Published in European Journal of Clinical Microbiology & Infectious Diseases
Natural Treatments for a Candida infection in the gut
Today we won’t be focusing on the individual treatment options for a Candida overgrowth.
Here is why.
There are too many variables that a good healthcare provider would need to know before recommending an approach. Valuable information such as previous antibiotic exposure, symptom presentation and possible co-infections (SIBO, large bowel dysbiosis and even parasite infections) need to be taken into account before treatments can start.
I will leave you with one (slightly orthodox) approach to bear in mind.
Feed your microbes.
The beneficial bacteria in your large bowel help to keep Candida in check and behaving itself. Many of these beneficial bacteria cannot be taken as a probiotic (these don’t stick around long anyway). They need to be fed.
Prebiotics, colonic foods, resistant starches and fibre, fibre, fibre (hence the image of the artichoke) will all help to nourish your microbiota. A nourished microbiota can then go on to do all the amazing things that help you feel great.
Have you noticed how I haven’t mentioned any herbal antimicrobials? Most of the time this isn’t necessary. Bringing your short chain fatty acid producing bacteria back online thus reducing the colonic pH is normally enough.
If you don’t tolerate prebiotics, resistance starch or fibre rich foods you may have more going on in your gut. If you need help with your digestive issues drop me a line here.
Do you have any experience with Candida infections or other digestive health problems. Share your thoughts below or feel free to ask a question.
References and Resources
- Candida albicans Biofilms and Human Disease
- Candida albicans biofilms: development, regulation, and molecular mechanisms
- Adaptive immune responses to Candida albicans infection
- Bifidobacteria and Butyrate-Producing Colon Bacteria: Importance and Strategies for Their Stimulation in the Human Gut
- Regulation of Candida albicans Morphogenesis by Fatty Acid Metabolites
- Beneficial effects on host energy metabolism of short-chain fatty acids and vitamins produced by commensal and probiotic bacteria
- Formation of propionate and butyrate by the human colonic microbiota
- Invasive candidiasis: from mycobiome to infection, therapy, and prevention