Coconut oil may significantly modulate the oral microbiome and reduce inflammatory markers in patients with periodontitis, according to the findings of a triple-blind randomized clinical trial.

Researchers, led by Simón Pardiñas López of the Clínica Medico Pardiñas, Spain, randomly assigned 30 participants diagnosed with periodontitis stages II and III (grades B and C), to three equal groups: coconut oil rinse, 0.12% chlorhexidine rinse, or placebo. Saliva and gingival crevicular fluid (samples were collected at baseline, 1 month after beginning the assigned mouth rinse, and 1 month after non-surgical periodontal therapy.

"Coconut oil treatment significantly modulated the oral microbiome and reduced inflammatory markers in patients with periodontitis, suggesting its potential as a natural and effective adjunct in periodontal therapy," the researchers noted in their findings in Clinical Oral Investigations.

Using next-generation sequencing and 16 S rRNA metabarcoding, it was found that coconut oil significantly reduced pathogenic bacterial families in the gingival crevicular fluid, including Spirochaetaceae and Tannerellaceae, while promoting beneficial bacteria such as Streptococcaceae. Coconut oil treatment demonstrated notable reductions in periodontal pathogens such as Tannerella forsythia and Treponema denticola.

The subgingival microbial dysbiosis index improved significantly in both the coconut oil and chlorhexidine groups, with a pronounced decrease observed between the second and third sampling points, demonstrating a significant shift toward a more balanced microbial profile.

Coconut oil also demonstrated significant anti-inflammatory properties. The coconut oil group showed a significant decrease in interleukin-6 levels over the entire study period and between the second and third sampling points when compared with placebo. Similarly, a significant reduction in TNF-α was observed in the coconut oil group between the first and third sampling points, with a statistically significant difference between coconut oil and chlorhexidine groups favoring coconut oil.

For the study, the researchers selected a pure virgin coconut oil with the highest lauric acid content (Superalimentos MundoArcoiris from Spain) after analyzing four commercial oils using gas chromatography. Participants in the coconut oil group were instructed to rinse vigorously with 5 ml of oil for 10 minutes after brushing at night, while those in the chlorhexidine and placebo groups rinsed for just 1 minute.

Coconut oil's antimicrobial properties derive primarily from its medium-chain fatty acids, particularly lauric acid. "In the case of gram-negative bacteria, the amphipathic nature of these compounds allows them to penetrate the bacterial membrane and form micelles that disrupt the membrane, leading to increased permeability, leakage of cell contents, and ultimately cell death," noted López. 

Unlike chlorhexidine, which is linked to side effects such as tooth and tissue staining, taste alteration, and hypersensitivity reactions with prolonged use, coconut oil may offer a natural alternative with minimal adverse effects.

The study's principal limitation was the relatively small sample size of 30 participants, indicating the need for larger-scale research to obtain more conclusive results.

The authors declared no competing interests.