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24 Apr 2020
Thrush is a very common health issue which affects 130 million women worldwide every year1. It can be a source of discomfort and frustration for many women. As such, more individuals are looking for natural options to help manage their symptoms and prevent recurrent infection. Probiotics have become a popular option. However, identifying the right probiotic to help combat thrush is important as some are much more effective than others. Some of the most well researched probiotic strains shown to help with thrush in clinical trials are Lactobacillus reuteri RC-14® and Lactobacillus rhamnosus GR-1®. These interesting strains are discussed in detail below.
Thrush is a fungal infection caused by a pathogenic (harmful) yeast. This can occur in the mouth (oral thrush) or in the genital area (vulvo-vaginal thrush). The typical symptoms of vaginal thrush include:
Women can often suffer with multiple bouts of thrush, the recurrence rates are quite high with a prevalence of 9% of women suffering between the ages of 25 to 34 years globally1. Traditional medical treatment involves the use of topical anti-fungal creams, anti-fungal pessaries or oral anti-fungal tablets. However, extensive use of these is contributing negatively to an already increasing rate of anti-fungal resistance in Candida spp2.
Thrush is typically caused by a pathogenic yeast known as Candida. Candida spp. lives naturally in the body - within the intestines, mouth, skin and vagina. In low numbers, they are usually considered harmless. The most common species of Candida that can cause thrush is Candida albicans.
Candida albicans (C. albicans) may increase in number when there is an imbalance, known as dysbiosis, in the microbiome. The human microbiome is the name given to the microbes that live on or within the human body including bacteria and yeasts. Collectively, they form an ecosystem. There is usually a delicate balance between the beneficial microbes and pathogenic microbes in our microbiome. Symptoms of thrush may develop when there is an overgrowth of C. albicans in the mouth or genital area. This overgrowth is believed to occur as a result of a disruption to our microbiome, leading to dysbiosis. This disruption may occur due to factors such as:
The vaginal microbiome is unique and differs from the oral and gut microbiome. A healthy vaginal microbiome should be dominant in the bacteria, lactobacilli. Lactobacilli can exert many protective effects to promote a healthy vaginal tract and reduce the risk of infections. When their levels are depleted, an imbalance may occur and opportunistic pathogens such as C. albicans can thrive.
Yes, probiotics may help with managing thrush. Clinical studies have shown that optimising one's friendly bacteria with probiotics can help to maintain a healthy vaginal microbiome. However, probiotics work in different ways- many work predominately in the gut. Not all lactobacilli will even reach the vaginal tract. It’s important to find probiotic strains that have evidence for vaginal colonisation and have clinical trials against thrush.
A number of clinical trials testing a combination of two particular probiotic strains, Lactobacillus reuteri RC-14® and Lactobacillus rhamnosus GR-1® have been shown to be hugely beneficial in supporting those suffering from thrush. The best probiotics for thrush include the two strains of bacteria, L. reuteri RC-14® and L. rhamnosus GR-1®, which are some of the most researched probiotics to date, and are certainly the most researched in terms of women's intimate health. You may like to read about further research behind these two strains on the Probiotics Database behind Lactobacillus reuteri RC-14® and Lactobacillus rhamnosus GR-1®
In a RCT by Martinez et al. 2009, 55 women diagnosed with vulvovaginal candidiasis were divided into two groups; one group received 2 billion CFU of Lactobacillus reuteri RC-14® and Lactobacillus rhamnosus GR-1® and the other group received a placebo for 4 weeks. Both groups initially were given 150mg of oral fluconazole. There was a significant reduction in vaginal discharge which corresponded with a reduction in yeast cell counts on vaginal swabs. More subjects with recurrent infection tested positive for Candida spp. on vaginal swabs compared with the probiotic group at the end of the 4 weeks (80% and 18.2% respectively)8. This shows that use of these two strains of probiotic bacteria alongside conventional oral anti-fungal medication, can enhance the efficacy of the antifungal medication. This is particularly relevant for individuals who suffer with vaginal thrush recurrently despite use of conventional treatments. In further studies by Anukam et al. 2009, oral supplementation with these two strains alongside conventional treatment resulted in reduced recurrence of future infections9.
Live yoghurts are a good source of friendly bacteria. It is beneficial to consume probiotic foods, such as live yoghurt, to boost our overall general health. Keeping our gut microbiome healthy by eating live yoghurt, will in turn help our vaginal microbiome, and help avoid an imbalance that could lead to thrush. However, the probiotic bacteria that are present in live yoghurt are not specific for vaginal health, and may not even reach the intimate area. Using a probiotic supplement that has been clinically researched for supporting vaginal health, may provide a much more targeted approach when managing thrush.
Lactobacillus reuteri RC-14® and Lactobacillus rhamnosus GR-1® have been shown to have anti-fungal properties. Both strains can produce lactic acid, this helps to lower the pH in the vaginal tract (pH 4 or below). This acidity creates an unfavourable environment for C. albicans, thus limiting growth. The probiotic strains can also adhere to the vaginal lining and create a physical barrier limiting the space and nutrients available for C. albicans (known as competitive inhibition)10. Furthermore, both strains may reduce inflammation associated with C. albicans infection. These strains inhibited the growth of Candida albicans through the production of anti-fungal, lactic acid and competitive inhibition, by utilising space and nutrients Candida albicans requires to grow .
Other lifestyle factors may need to be considered when managing or reducing the risk of thrush
Try to avoid:
Although women suffer from vaginal thrush, less commonly, men can also develop genital thrush.
The above information relates predominantly to vaginal thrush. More scientific research is needed but preliminary studies do support the theory that probiotics could have a role to play in the management of oral thrush. As a health care professional you might find the following blog post interesting: Could probiotics help with oral thrush?
This article was last updated on 24th of April 2020.
This article was written by Dr Aisling Dwyer MB BCh BAO (Medicine, Surgery and Obstetrics), MSc (Personalised Nutrition) in collaboration with Kathy Wheddon (Nutritional Therapist DipION) and was last updated on 6th April 2020.
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