Fungi are everywhere. From the bacteria that live in your gut to the microscopic organisms that live in your shower, there are over 2.3 million species of fungi, living in every possible niche of the planet and providing countless benefits to humans and the environment.
Of course, just because fungi can be found everywhere doesn’t mean they’re always beneficial. In fact, many fungi are more than capable of causing infections and illnesses, including skin, nail, and throat infections. As fungus-based infections continue to grow in prevalence, maintaining a healthy immune system is more important than ever.
Luckily, thanks to their natural antifungal properties, many herbal remedies are becoming increasingly popular alternative treatments for fungal infections and conditions.
In this edition, we’re leveraging ancient wisdom (backed by science!) and building on the exploration of foods as antifungal agents by looking at the role of herbs and spices in combating fungal infections.
Read on for eight herbs, spices, and supplements to consider incorporating into your diet to prevent fungal overgrowths.
Some of the Best Natural Antifungal Herbs and Supplements
Oregano essential oil, derived from the leaves and flowers of the oregano herb (Origanum vulgare), is one of the most commonly used culinary herbs. It has also been consumed for centuries for its medicinal properties, dating back to ancient Greek and Roman civilizations.
More recently, oregano oil’s antifungal properties have come under the microscope, with research showcasing its ability to not only inhibit the growth of Candida but also act as a powerful preventive. This is thanks to two naturally-occurring antimicrobial agents found in oregano oil, carvacrol and thymol. (Source)
Cinnamon’s potent antifungal properties make it a powerful ally in the fight against yeast infections. In 2012, one study found that cinnamon oil was able to break down the biofilm of C. albicans in the gut. After just 14 days of treatment, 72% of the patients were found to have no Candida at all in their stool, while the other 28% showed a significant reduction in the yeast. However, it is not clear what the clinical significance of this is. (Source)
Turmeric (Curcuma longa) is another natural substance that has been shown to have potent antifungal properties. A study that tested eight of turmeric’s chemical constituents against pathogenic fungi found they all had some effect on fungi growth. While this study involved fungi typically found on plants, the mechanism of action may apply to fungi that plague humans as well. (Source)
It is worth noting that while turmeric contains curcumin, the compound that gives the spice its distinct golden color and taste, the greatest fungal-inhibiting effects may actually be due to another compound called curdione. Although curcumin alone can also inhibit fungal growth, turmeric may offer stronger benefits, so add a shake of the earthy spice into your next meal. (Source, Source)
Derived from the inner bark of several Tabebuia tree species, pau d’arco — also known as taheebo or lapacho — is a dietary supplement endemic to South America. Due to its reported antifungal and anti-inflammatory properties, pau d’arco is often consumed as an herbal tea for a wide range of inflammatory ailments and infections.
While the exact mechanism remains unknown, pau d’arco is thought to inhibit the processes fungi need to produce oxygen and energy. (Source, Source) Findings from studies suggest that the bark extract may protect against and prevent the growth of disease-causing fungi. (Source) However, further studies are needed to look at the effectiveness of pau d’arco extract for infections in humans specifically.
Extracted from coconut and palm kernel oils, caprylic acid can be used topically to help treat skin infections, thanks to its antimicrobial properties. Caprylic acid is also commonly sold as an over the counter supplement for oral and vaginal candidiasis. Its short-chain fatty acids penetrate the cell wall of the yeast and cause it to rupture, preventing its growth.
Although undecylenic acid is primarily used in the form of a topical antifungal treatment, the unsaturated fatty acid derived from castor oil is also commonly consumed as a dietary supplement for its alleged antifungal and antibacterial properties.
The fungicidal effects of undecylenic acid — especially on the skin — are largely attributed to its organic fatty acid components. Fatty acids prevent the spread of C. albicans and the formation of biofilms, large communities of fungi cells that attach to each other and to surfaces. These factors play a critical role in the development and progression of skin infections as well as Candida’s ability to grow throughout the body. (Source)
Berberine, an alkaloid that is commonly found in plants like goldenseal (Hydrastis canadensis) and barberry (Berberis vulgaris), has been used for centuries in Ayurvedic and Chinese medicine to treat digestive disorders and infections. In recent years, berberine has received a great deal of attention in the scientific community due to its potent anti-obesity and anti-diabetic activities. (Source, Source)
It turns out that berberine has also been shown to have strong antifungal properties. Researchers have found that berberine effectively inhibited the growth of various kinds of pathogens that may lead to candidiasis in the gut. The herb appears to heal and support the microbiome when gut cells have been damaged by bacteria. (Source)
Grapefruit Seed Extract
Grapefruit seed extract (GSE) is derived from the seeds and pulp of grapefruit. A natural disinfectant, GSE is often used as a preservative in food and beverages, and as a natural cleaner for homes. It is often used in conjunction with other essential oils, such as tea tree oil, to enhance efficacy.
Studies have suggested grapefruit seed extract may be effective against a variety of yeasts, molds, and bacteria. Amazingly, it’s able to work its magic within 15 minutes of contact (even when diluted!). (Source, Source) Some studies, however, have found that many GSE products have disinfectants added to them that may account for the extract’s alleged effects, so more research is needed. (Source)
A derivative of the amino acid cysteine, N-acetyl cysteine (NAC) is an antioxidant that is primarily used to treat acetaminophen overdose and liver conditions such as acetaminophen-induced liver damage and chronic viral hepatitis. More recently, NAC has been studied for its potential to treat and prevent yeast infections, nail fungal infections, and oral thrush.
In a study that investigated the efficacy of NAC as a treatment for vaginal yeast infections in mice, researchers observed that “NAC treatment of vaginal candidiasis significantly suppressed yeast burden in the vagina” and “there was no significant difference in the extent of suppression of yeast growth between NAC and fluconazole.” They concluded that “oral NAC may be a potential alternative treatment for vaginal candidiasis.” (Source)
Tea Tree Oil
Derived from the leaves of the tea tree (Melaleuca alternifolia), tea tree oil has demonstrated various biological activities, including antifungal activity. In a study that examined the antifungal activity of tea tree oil against 10 different fungal species, researchers found that tea tree oil was effective against both yeast and mold species. In fact, they found that tea tree oil was more effective against the yeast species than the mold species.
Dill oil, like caraway, is another culinary herb that has been shown to have antifungal properties. In one study, researchers tested the antifungal activity of dill oil against two standard strains of Candida and a number of clinical strains that were derived from patients with yeast infections. The researchers found that dill oil was effective against the majority of the clinical strains tested. The researchers concluded that “[t]he results [of the study] suggest that the essential oil of dill could be a potent antifungal agent.”
A second study that examined the antifungal properties of dill oil against a larger number of clinical strains of Candida found that “dill oil showed a strong inhibitory activity against C. Albicans, both in vitro and in vivo.” The authors concluded that dill oil “is a potential natural candidate for the treatment of Candida infection.”
Dill oil has been used in Ayurvedic medicine since ancient times. Dill has been reported to possess antibacterial properties, making it a potential source of an eco-friendly antifungal drug.
The essential oil extracted from the seeds of dill (Anethum graveolens L.) was demonstrated in a study showing its ability to disrupt the permeability barrier of the plasma membrane, which can help eliminate fungus-causing bacter (Source)
Boric acid, also known as borax, is a naturally occurring mineral compound that is associated with a range of health benefits. Although boric acid is most commonly used as an eyewash to treat eye infections, it has been used to treat a variety of other conditions, including vaginal yeast infections, fungal infections of the mouth, and warts.
Boric acid has antibacterial properties, making it a great, affordable home remedy for fungus. Research shows that boric acid suppository capsules appear to be very effective against yeast infections, particularly those caused by Candida. An early study found that boric acid suppositories, when taken nightly for 7 to 10 days, have up to a 92 percent cure rate. That is a strong number!
The journal Diabetes Care found that boric acid vaginal suppositories were more effective against Candida infections in diabetic women than an oral azole medication and the Journal of Women’s Health found that it’s a safe alternative for the treatment of four or more infections in a single year that is caused by non-albicans Candida.
However, boric acid can occasionally cause vaginal burning, should be diluted or used with the guidance of a doctor, is toxic when swallowed and shouldn’t be used frequently or when pregnant.(Source, Source)
Black walnut (Juglans nigra) is a large tree native to North America that is rich in tannins and juglone, a chemical compound that makes the nuts inedible to people. In fact, the compound is so potent that it is used as a natural pesticide and preservative for wood.
The antimicrobial qualities of black walnut have also been of interest to researchers in recent years. In a 2015 study in which researchers tested the efficacy of black walnut extract on a variety of fungal strains, they found that black walnut extract was able to inhibit the growth of all strains. And in a 2016 study in which researchers examined the antifungal activity of black walnut, they found that it was able to inhibit the growth of several strains of Candida, a fungus that can cause systemic infections in immunocompromised patients.
As with other natural antimicrobials, more research is needed to determine the appropriate doses and application of black walnut extract.
It’s been suggested that the biological activity of the black walnut hull is due to the naphthoquinone, juglone (5-hydroxy-1,4 naphthoquinone). The antifungal activity of juglone has also been compared to other known antifungal agents, such as griseofulvin, clotrimazole, tolnaftate, triacetin, zinc undecylenate, selenium sulfide, liriodenine and liriodenine methionine.
In a study, it was determined that juglone exhibited moderate antifungal activity similar to zinc undecylenate and selenium sulfide, which are commercially available antifungal agents. (Source)
Calendula, also known as pot marigold or garden marigold, is a plant in the daisy family. It is native to the Mediterranean region, but has become naturalized in many other locales. Calendula has been traditionally used to heal wounds and to treat infections, and it is also valued as a medicinal herb for the treatment of gastrointestinal, respiratory, and urogenital disorders.
The essential oil of calendula is used as a natural antifungal agent to treat fungal infections of the skin, mouth, and nails. It is especially effective for the treatment of athlete’s foot and other types of ringworm, and has also shown promise in fighting candidiasis and other forms of vaginitis. (Source, Source)
Milk Thistle Extract
Milk thistle (Silybum marianum) is a flowering plant native to southern Europe and the Mediterranean region. Extracts of the seeds and leaves have been used in traditional medicine to treat liver and gallbladder disorders, as well as heart disease and cancer. Milk thistle is also used to soothe digestive disorders and skin conditions like eczema, boils, psoriasis, and acne. In addition, milk thistle has been used to treat fungal infections like Candida, ringworm, and athlete’s foot.
Milk thistle contains a complex of bioactive compounds called flavonolignans, which have been shown to have antifungal activity. In one study, researchers found that silybin, a type of flavonolignan found in milk thistle, has “considerable antifungal activity” against a variety of pathogens. In another study, researchers found that silymarin, the active compound in milk thistle, has potent anti-Candida activity.
Echinacea has a long history of use in Native American medicine, where it was used for the treatment of respiratory and skin infections, as well as for snake bites and other wounds. However, this herb is most well-known for its purported use as a cold and flu remedy.
According to a study in which researchers tested echinacea’s ability to prevent rhinovirus infection, echinacea has strong antiviral activity in the form of “nucleoprotein inhibition,” which means it can stop the virus from replicating and spreading to other cells. In the study, “elderberry and echinacea were found to be the most potent at inhibiting the rhinovirus.”
In addition, echinacea’s antifungal properties are well documented. In a study that examined the effectiveness of echinacea, goldenseal, and myrrh against Candida, researchers found that “echinacea demonstrated the greatest antifungal activity.”