candida overgrowth: the full lowdown

Written by Maeve Hanan

Candida overgrowth is a type of fungus or yeast which grows all over the human body, especially in warm and moist areas like the mouth, stomach and vagina.

The presence of candida isn’t usually a problem unless an overgrowth occurs (1). Although candida overgrowth is quite common, the severity of these infections vary greatly (2).

Candida overgrowth is also called:

Candidiasis
A Candida infection
A yeast infection
A fungal infection
Thrush

A yeast allergy is a rare food allergy – this is a separate condition which has no clear connection to Candida overgrowth (3).

There are more than 150 known species of Candida, but only 15 of these are thought to be linked with Candida infections (4). Candida albicans is the species most commonly associated with candida overgrowth.

the risk of this is higher for those who have (1):

A weakened immune system e.g. AIDS, cancer or poorly controlled diabetes
Liver damage
Used antibiotics for a prolonged period
An imbalance of bacteria in the gut
High-stress levels

Some studies have found that using proton-pump inhibitor medication (PPIs) increases the risk of candida overgrowth in the oesophagus (food pipe) (5). The reason for this isn’t entirely clear, but it may be related to a reduction in stomach acid.

There is no good evidence that Candida overgrowth leads to ‘leaky gut syndrome’, you can find out some more about that here.

common symptoms:

How do I know if I have Candida?

The symptoms of Candida overgrowth vary, depending on where it occurs, the type of infection and the severity of this.

Fungal infections in the skin usually present as an itchy red rash, which often occurs in skin folds. In the toenails this can cause discoloration and splitting of the nails.

Oral thrush causes redness, pain, cracking and white lesions in the mouth and tongue. In the throat this can also cause difficulty with eating or swallowing.

Genital thrush leads to redness, itching, irritation and white discharge. Urinary yeast infections can cause a burning pain while peeing and an increased urge to urinate.

symptoms of candida overgrowth in the gut include:

Stomach pain
Diarrhea
Constipation
Bloating
Gas
Nausea

Headaches, tiredness and memory problems are sometimes claimed to be symptoms of candida overgrowth, however, these are not recognised symptoms.

Symptoms of candida overgrowth in the gut overlap with a variety of gut issues. So it is important to see your doctor to rule out other medical conditions, and to see whether you might have a Candida overgrowth.

how is it diagnosed?

Candida overgrowth is diagnosed by a doctor who examines the affected area in the context of your symptoms and medical history.

Samples of skin, nail, discharge or a swap of the mouth may be taken and examined under a microscope. These samples, along with blood samples from the infected area, can also be tested to see whether Candida grows when these are placed in a fungal culture (6).

Candida overgrowth in the oesophagus is usually diagnosed using a camera which goes down the throat. Sometimes a sample of tissue (biopsy) is taken during this procedure so it can be tested for the presence of Candida (5).

‘Candida hypersensitivity’ or ‘yeast hypersensitivity’ is not a diagnosis which is backed by science. Remember that it is normal to find Candida in our body, and this only causes a problem if it leads to a Candida overgrowth or infection.

management options:

Antifungal medication is usually used to treat Candida overgrowth. For more information on antifungal medication, check out this post from NHS Choices.

Colonic irrigation is sometimes promoted as a management option for Candida overgrowth, but this is not backed by evidence and is potentially harmful. See here for more information about this procedure.

There are claims that ‘the Candida diet’ can be used in the management of this condition. This is a low sugar diet which: excludes gluten and alcohol, limits dairy, encourages fermented foods and probiotics. However, there is no good evidence to suggest that this diet works. For example, although certain types of sugar promote the growth of Candida in a petri dish and may increase its ability to stick to surfaces, this research can’t be directly applied to the human gut at present (7). Similarly, there is a higher risk of Candida overgrowth in those with coeliac disease (related to changes in the immune system), but there is no evidence that gluten increases the risk of Candida overgrowth in those who don’t have coeliac disease (8). There is also no evidence that a yeast-free diet is helpful in the management of Candidiasis.

In fact, following a restrictive diet like ‘the Candida diet’ can be counterproductive, as this can be bad for the immune system and overall health.

A more helpful approach is to focus on a balanced Mediterranean-style diet which includes a variety of plants, plenty of fibre and healthy fats – alongside medical treatment for the Candida overgrowth.

Probiotics may have a role in the management of Candida overgrowth, by restoring a healthier balance of microflora, but there currently isn’t much evidence to support this (9 – 10). Read more on probiotics here.

where to find support:

Speak to your GP if you suspect that you might have a Candida overgrowth
NHS Choices Fungal Infection Community

other useful resources

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about the author

Maeve Hanan is a Dietitian, registered in both Ireland and the UK, with a passion for spreading evidence-based nutrition messages. She has a range of clinical, consultancy, media and writing experience.

references:

Martins et al. (2014) “Candidiasis: Predisposing Factors, Prevention, Diagnosis and Alternative Treatment”. Mycopathologia; 177: 223.
Felix et al. (2017) “Global and Multi-National Prevalence of Fungal Diseases—Estimate Precision”. J Fungi (Basel); 3(4): 57.
Cunningham (2013) “Is there a diet for “yeast allergy”?”. J Acad Nutr Diet; 13(3):484.
Yapar (2014) “Epidemiology and risk factors for invasive candidiasis”. Ther Clin Risk Manag; 10: 95–105.
Nassar et al. (2018) “Possible Risk Factors for Candida Esophagitis in Immunocompetent Individuals”. Gastroenterology Res; 11(3): 195–199.
CDC Website (2019) “Diagnosis and Testing for Invasive Candidiasis” [accessed May 2019 via: https://www.cdc.gov/fungal/diseases/candidiasis/invasive/diagnosis.html]
Pizzo et al. (2000) “Effect of dietary carbohydrates on the in vitro epithelial adhesion of Candida albicans, Candida tropicalis, and Candida krusei”. New Microbiol; 23(1):63-71.
Hartnett et al. (2017) “Significantly higher faecal counts of the yeasts candida and saccharomyces identified in people with coeliac disease”. Gut Pathog; 9: 26.
Falagas et al. (2006) “Probiotics for prevention of recurrent vulvovaginal candidiasis: a review”. Journal of Antimicrobial Chemotherapy; 58 (2): 266–272.
Ohshima et al. (2016) “Therapeutic Application of Synbiotics, a Fusion of Probiotics and Prebiotics, and Biogenics as a New Concept for Oral Candida Infections: A Mini Review”. Front Microbiol; 7:10.