Written by Joyce Smith, BS. This study demonstrates how dietary coconut significantly decreased colonization of Candida albicans by altering the metabolic gene expression of the C. albicans cells.
Candida albicans is part of the normal gut flora; however, when immune systems are compromised, this common fungal pathogen can colonize the digestive tract, causing systemic infections 1 that carry a mortality rate of approximately 40% 2. The most effective way to reduce candidemia-associated mortalities is to prevent the colonization of this potential pathogen. 3 The medium chain fatty acids, decanoic and dodecanoic acids, present in coconut oil have been shown to inhibit and destroy C. albicans growth in vitro 4 while the long chain fatty acids, particularly hexadecanoic and octadecanoic., present in beef tallow and soybean oil support its growth 5. Therefore, researchers, hypothesizing that dietary coconut oil might reduce GI colonization by C. albicans in vivo, chose to test and compare the effects of dietary beef tallow, soybean oil, and coconut oil on the colonization of C. albicans in a mouse model 6. Thirty-two to forty-eight mice were fed a high fat diet containing either coconut oil, beef tallow, or soybean oil, or a control diet (AIN-93G), and inoculated orally with C. albicans. Twenty-one days later the extent of gastrointestinal colonization was measured. The following is a summary of the results.
C. albicans colonization was significantly lower in the coconut oil fed mice compared to those fed beef tallow (p<0.001), soybean oil (p<0.001) or the standard AIN-93G (p<0.001) diet. Colonization was also significantly lower in the cecal contents and fecal pellets of the coconut oil fed mice compared to cecal contents and fecal pellets of the beef tallow fed mice (p=0.002, p=0.01) respectively or the soybean oil fed mice (p=0.007, p=0.007) respectively, thus validating for researchers that dietary coconut oil inhibited GI colonization by C. albicans to a significantly greater extent than dietary beef tallow or soybean oil. Researchers, switching beef tallow-fed mice to a coconut oil diet, found that coconut oil significantly reduced any preexisting colonization (even though the diet contained beef tallow as well (p=0.01).
Researchers speculate that any direct antimicrobial effects exerted by the MCFAs in coconut oil probably occur in the upper part of the GI tract, because MCFAs are mostly absorbed in the small intestine and are therefore scarce in the contents of the cecum and colon. Consistant with this hypothesis, dietary coconut oil did have a greater impact on colonization in the stomach than on colonization in the cecum or fecal pellets. (Coconut oil consists primarily of medium-chain fatty acids (MCFAs), which are fungistatic and fungicidal for C. albicans. Coconut oil is ~45% dodecanoic acid (12:0) 7, which has been shown both to inhibit C. albicans growth 8 and to kill C. albicans within 30 min 8. These results were similar with decanoic acid (10:0), which is also present in coconut oil 7,8). Thus, the antimicrobial properties of MCFAs may indeed contribute to the reduced colonization observed in the GI tracts of coconut oil-fed mice.
In addition to directly decreasing GI colonization by C. albicans, dietary coconut oil altered the metabolic program of the colonizing cells. Long-chain fatty acids were less abundant in the cecal contents of mice fed coconut oil-containing diets than in the cecal contents of mice fed a diet rich in beef tallow and the expression of C. albicans fatty acid catabolic genes were lower in the coconut-fed mice than in the beef tallow-fed mice. The authors suggest that “the metabolic adaptations by C. albicans in response to the availability of long-chain fatty acids in the GI tract may contribute to the robust colonization seen in beef tallow- and soybean oil-fed mice compared to coconut oil-fed mice. Importantly, even when the diet contained beef tallow, these metabolic adaptations were completely ablated by dietary coconut oil. Therefore these results suggest that adding coconut oil to a patient’s existing diet could both reduce colonization and alter the metabolic program of colonizing C. albicans cells.”
The next step is to replicate this study in humans using a reasonable dose of coconut oil.
Source: Gunsalus KTW, Tornberg-Belanger SN, Matthan NR, Lichtenstein AH, Kumamoto CA.2015. Manipulation of host diet to reduce gastrointestinal colonization by the opportunistic pathogen Candida albicans. mSphere 1(1):e00020-15. doi:10.1128/ mSphere.00020-15.
© 2015 Gunsalus et al. Creative Commons Attribution 4.0 International license.
Click here to read the full text study.
Posted December 7, 2017.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
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- Gunsalus KT, Tornberg-Belanger SN, Matthan NR, Lichtenstein AH, Kumamoto CA. Manipulation of host diet to reduce gastrointestinal colonization by the opportunistic pathogen Candida albicans. mSphere. 2016;1(1):e00020-00015.
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