MTHFR Candida Infections and the Gut Brain Connection

Written By:

Katie Stone - Naturopath

Medical Reviewer:

Dr. Nare Simonyan - PhD Pharmaceutical Science

Edited By:

Kari Asadorian - BSN, RN

Last updated: April 29, 2026

MTHFR, Candida Infections, and the Gut-Brain Connection

Candidiasis is an increasingly common condition, with around 25,000 cases¹ recorded nationwide each year. It is an opportunistic infection caused by Candida, a type of fungi, and typically colonizes the oropharyngeal, esophageal, and gastrointestinal mucosa.

Candida infections are particularly common in immunocompromised individuals². However, research suggests that poor methylation associated with MTHFR mutations may also play an important role in susceptibility due to reduced methionine synthase.

The gut-brain connection is also impacted by Candida infection, which can exacerbate symptoms of MTHFR.

This article will explain what a Candida infection is and its symptoms, how it can interfere with methylation, and how you can treat a Candida infection if you have an MTHFR SNP(s).

What is a Candida Infection?

Candida albicans remains the leading cause of invasive Candidiasis³ in the United States, affecting an estimated 9 per 100,000 people⁴.

Candida albicans is an opportunistic yeast, the most prevalent fungal species of the human microbiota. It lives naturally in the body and is usually kept under control by other gut microbiota.

Candida overgrowth can occur⁵ when the immune system is altered, usually due to antibiotics. Stress can also affect the gut microbiome that controls Candida, as well as infection by another microbe, immunosuppressant therapy, poor nutritional intake, or changes to the local environment.

These circumstances can enable C. albicans to overgrow and result in a wide range of infections affecting the skin, digestive function, brain function, mouth, and more.

Candida albicans depends upon glycolysis⁶ to progress, and glucose and other sugars⁷ influence the ability of Candida cells to form a biofilm.

The Candida biofilm is largely resistant to current antifungal drugs such as fluconazole. No biofilm-specific drugs exist today for C. albicans (or any microbe), making treatment of biofilm-based infections particularly problematic.

However, treatment with probiotics and natural antifungal agents⁸ has proved successful in some cases.

If left untreated, Candida-related infections can become painful and irritating and may severely affect digestion and skin health.

Symptoms of a Candida Infection

Candida overgrowth can affect the mouth, genitals, skin, and digestive system. Recent research in mice suggests it may also affect cognitive function.

Gastrointestinal issues⁹ (bloating, constipation)
White patches¹⁰ on the tongue, throat, and other mouth areas (oral thrush)
Itching, soreness, abnormal discharge¹¹ in the genital area (vaginal thrush)
Fungal infection of the skin and/or nails¹²
Cravings for sugar¹³ and/or simple carbohydrates
Possible impaired memory¹⁴ or reduced cognitive function

How Candida Can Interfere with Methylation

Candida may also interfere with the methylation cycle by producing acetaldehyde¹⁵, along with the associated yeast infection. Acetaldehyde is a highly reactive and toxic chemical that inhibits both methionine synthase¹⁶ and glutathione.

Methionine synthase is a crucial component of the methylation process. It is required for donating a methyl group to homocysteine¹⁷ from 5-methyltetrahydrofolate, which allows the conversion of homocysteine back to methionine.

This process is already compromised in those with MTHFR mutations due to the inactive or malfunctioning MTHFR enzyme, which can mean that a Candida infection may increase their risk of elevated homocysteine.

Researchers have suggested that methionine plays an essential role in preventing the toxic accumulation of homocysteine¹⁸ when Candida is present.

Candida overgrowth in the gut can also affect brain chemistry via the gut-brain axis. One study found that mice colonized with Candida albicans demonstrated anxiety and increased stress hormone levels¹⁹ due to changes in the endocannabinoidome.

Other research has found possible links between mental illness and the gut microbiome. The gut is closely connected with the central nervous system (CNS), as shown by the high incidence of neurological symptoms²⁰ in IBS (Irritable Bowel Syndrome) sufferers.

Patients with schizophrenia have a higher incidence of Candida infection, along with gastrointestinal dysfunctions and poorer cognitive ability²¹. Children with autism spectrum behaviors²² are also found to have increased levels of Candida.

The microbiome is responsible for synthesizing important mediators that influence the central nervous system and can therefore play a specific part in the microbiota-gut-brain axis²³ disturbance.

It is also known that Candida albicans can produce histamine²⁴, which is a crucial neuromodulator in regulating sleep rhythm, appetite, and cognitive actions.

How to Deal with Candida if You Have an MTHFR Mutation

Treating a Candida infection requires a multi-pronged approach.

Diet

Limit sugars, simple carbohydrates, and alcohol. Candida albicans uses glucose and other sugars to proliferate. Focus on whole foods, fresh fruits and vegetables, and plenty of filtered water.

Immune support

Around 70 percent of the body’s immune cells live in the gut, which means the gut microbiome plays a significant role in systemic immunity.

Supporting immune function with a comprehensive multivitamin can help fill in any diet gaps, especially if you are at risk of nutritional deficiencies due to an MTHFR mutation. Methyl-Life’s range of methylated multivitamins is designed to support vegans, vegetarians, and individuals with MTHFR.

Probiotics

Support a healthy gut microbiome by taking probiotic supplements. Probiotic bacteria from the Lactobacillus and Bifidobacterium²⁵ species and probiotic yeasts such as Saccharomyces boulardii²⁶ have been found effective in reducing Candida albicans infection.

Spore-based probiotics have advantages over other probiotics as they can survive the harsh gastric conditions of the stomach²⁷ and intestines and eventually germinate in the digestive tract. The probiotic supplement Mega SporeBiotic™ is a 100% probiotic blend of 5 Bacillus spores that have been shown to maintain healthy gut barrier and immune function²⁸.

RestorFlora™ is also highly recommended for those with Candida overgrowth. RestoreFlora™ is a blend of the probiotic yeast Saccharomyces boulardii, Bacillus subtilis HU58, and Bacillus clausii SC109. These well-researched strains support digestive flora and help to maintain a healthy intestinal environment.

Both Mega SporeBiotic™ and RestorFlora™ contain Bacillus subtilis, which has been shown to help fight Candida albicans²⁹.

Starting a probiotic regimen may have some unpleasant symptoms as the gut microbiome is altered, but these eventually pass. Please seek the advice of a medical professional before commencing any new supplement regimen.

References

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About the Author

Katie is a qualified Naturopath (BNatMed) and freelance writer from New Zealand. She specializes in all things health and wellness, particularly dietary supplements and nutrition. Katie is also a dedicated runner and has completed more half-marathons than she can count!

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MTHFR, Candida Infections, and the Gut-Brain Connection

MTHFR, Candida Infections, and the Gut-Brain Connection

What is a Candida Infection?

Symptoms of a Candida Infection

How Candida Can Interfere with Methylation

How to Deal with Candida if You Have an MTHFR Mutation