Candida infections are a relatively common form of fungal overgrowth. Oral, vaginal, and cutaneous thrush are mild forms of candida infections. Invasive candidiasis is a more serious form of fungal overgrowth that is life threatening and can affect the blood, heart, brain and eyes.
There are a number of Candida species that lead to fungal overgrowth. The most common are C. albicans, C. glabrata, and C. tropicalis. Normally, they live within us causing nary a problem. In fact, they’re likely beneficial.
But when they get out of control, they cause problems. In today’s blog we’ll discuss why this happens and one of the main tools our body uses to prevent them.
It’s actually a pretty cool trick.
How do candida infections occur?
Candida normally lives in us as a commensal species in its yeast form. The respiratory tract and GI tract contain C. albicans in mucus membranes. Mucus membranes in the female genital tract also contain C. albicans.
However, Candida species convert into fungal forms under certain circumstances. In fungal form, they adhere to tissues and damage them. This normally happens when we’re immuno-compromised. As a result, candida infections are also referred to as opportunistic infections.
Unfortunately, the terminology is a bit confusing because people use them interchangeably. A yeast infection, fungal infection, yeast overgrowth, Candida overgrowth, and Candida infection all refer to the same thing.
Yeast infection and yeast overgrowth are sort of misnomers. In the yeast form, Candida is benign or beneficial. In order for Candida species to cause problems, they have to convert to their fungal forms.
Ultimately, the most important thing to understand is that your body dictates what happens with Candida. You don’t need nor want to eradicate C. albicans from your body. And you can’t starve it.
You want your immune system to keep it in check. When this doesn’t happen, your problem isn’t with Candida, it’s with your immune system.
A new paper gives us a glimpse in to how this process works.
Immunoglobulin A helps keep things in check
Whether Candida is in the yeast or fungal form largely depends on the environment it’s in. When the environment permits conversion to the fungal form, it uses virulence factors that help it bind to and damage our tissues.
This doesn’t happen in the yeast form, so Candida yeast really can’t infect anything. Fortunately, a new paper shows that our immune system uses something called secretory immunoglobulin A(sIgA) to accomplish this task.
We secrete sIgA into our mucus membranes to help prevent against infection. New research shows that sIgA preferentially binds to virulence factors on the fungal form of candida. This helps prevent adhesion of the fungus to our tissues, and promotes removal.
Consequently, this response helps maintain Candida in our mucus membranes in the yeast from, and prevents Candida infection. (Note: infection=invasion of tissues)
As an interesting aside, Candida in the yeast form actually helps induce sIgA. As you can imagine, this makes eliminating it a fairly bad idea.
So when you have a fungal overgrowth, you should focus on addressing the immune problem. “Starving Candida” should be the last thing on your mind.
Preventing Candida infection
Whether you want to fix or prevent a Candida infection, bolstering your immune system is the way to go. Certain lifestyle factors are crucial to maintaining a healthy immune system.
Type 2 diabetes and obesity both increase the risk of fungal infection. Increased systemic inflammation is believed to be driving the increased risk in these populations. As such people with Type 2 diabetes and the obese who regularly experience fungal infections benefit from weight loss.
People with IBD also have an increased risk for fungal infections. Those with Crohn’s disease have a higher fungal load in the gut than healthy controls. This correlated with decreases in sIgA in Crohn’s patients.
Finally, circadian rhythms regulate the secretion of sIgA. In saliva, sIgA levels peak in the morning as we wake up. This anticipatory secretion is commonplace for circadian rhythms.
In this paper, light didn’t have any effect on sIgA. However, they used low intensity light similar to what you’d see in an office building (~250lux). Another small study from 1999 found that greater exposure to high intensity light during the day(5000 lux) led to higher sIgA levels.
New data from mice indicates that feeding times primarily regulate the sIgA rhythm. Feeding mice during their normal fasting time reverses the circadian rhythm of sIgA.
Interestingly, the rhythm of sIgA helped create rhythms in the members of our microbiome as well as their metabolites.
This is an important concept to grasp for building a healthy microbiome. Other antimicrobial peptides such as Reg3g are secreted in a circadian manner, and this helps shape the microbiome. Interestingly, this is regulated by attachment of segmented filamentous bacteria, which also follow a rhythm.
The rhythms of our microbes and gut are intricately linked to one another. Disruption in one disrupts the other, and this leads to chaos in the gut. If you want to learn more, we covered this topic in a Youtube video trailer called Syncing your microbial clock you can check out here.
Candida infections are opportunistic in that they pop up when our immune system fails to maintain Candida in the yeast form. This isn’t a product of how much Candida is there, it’s supposed to be there. Rather, it’s a product of yeast to fungal transition.
Secretory IgA pays an important role in maintaining Candida in the yeast form. It recognizes virulence factors that allow adhesion to tissues and cause damage.
Candida yeast actually induce the production of sIgA to prevent yeast to fungal transition. So, eliminating the yeast form is likely not in your best interest.
Several lifestyle factors play an important role in preventing Candida infections. This includes identifying a diet that allows you to maintain a healthy weight and blood glucose control, eating in a way that minimizes inflammation in the gut, and creating strong, robust circadian rhythms that align with behavioral rhythms.
This aligns your sIgA rhythm with your feeding rhythm, preventing yeast to fungal transition and Candida infection. If you already have a fungal overgrowth, antifungals can help remove the overgrowth, but minimizing re-occurence is contingent on following the above guidelines.