Microbial diversity in the gastrointestinal tract, especially with a higher number of commensal species, supports many avenues of health. The intestinal microbiota may contain up to 1,500 species that come from more than 50 different phyla. A healthy microbiome has a higher number of commensal species and greater diversity. An increase in potentially pathogenic species or other disruptions in the gut microbiota population may interrupt this microbial balance. Studies have demonstrated a potential association between dysbiosis in the gut microbiome and chronic conditions, including irritable bowel disease, inflammatory bowel disease, autoimmune diseases, metabolic disease, cardiovascular disease, mental health conditions, and neurodegenerative disorders.

Some herbs may have the potential to promote a healthy microbial diversity in the gut, either by supporting commensal bacteria or by inhibiting potentially pathogenic species. One such herb is oregano. Oregano has a long history of use in traditional medicine, especially in treating infections and gastrointestinal complaints. Research supports the potential for oregano to support an immune response against potential threats and promote healthy microbial diversity in the gut.* 

Oregano may have antibacterial, antifungal, and antiparasitic properties. One in vitro study tested six essential oils (including oil of oregano) against nine bacterial strains that included both gram-positive and gram-negative species. Oregano was extremely effective on all tested bacteria, with inhibition zones that ranged from 26 mm to 54 mm in diameter. The same study also tested oregano on five fungal strains, and oregano demonstrated antifungal activity on all strains. 

Oregano may target potentially pathogenic species without affecting the microbiome at large, which helps promote a healthy microbial diversity in the gut.* In an in vitro study, researchers tested oil of oregano on standardized cultures of the bacteria Staphylococcus aureus, Escherichia coli, and Streptococcus pyogenes. Oil of oregano was extremely effective with all three strains. The same study then assessed the effect of oil of oregano supplements for minor infections in patients with metabolic syndrome. There was a lower number of infections at the end of the follow-up period compared to the baseline. The patients also experienced a reduction of gastrointestinal symptoms post-treatment. The researchers postulated this was due to oregano not affecting the commensal species in the gut microbiota.

Herbs such as oregano feature several bioactive compounds that may promote health.* Adding these to the diet is one way to potentially benefit from the benefits of these herbs. Additionally, studies demonstrate the potential for oil of oregano supplements to promote a healthy microbial diversity in the gut, which may also help support overall health.* 

By Kendra Whitmire, MS, CNS