For much of modern medical history, the appendix was considered vestigial, an evolutionary leftover with no meaningful function. Surgical removal was common practice, often performed even in mild cases of inflammation. In recent years, however, accumulating evidence has challenged this perception. Research, supported by years of anecdotal experience, now suggests the appendix plays significant roles in neural communication, immune regulation, and the preservation of gut microbial diversity.

Neural and Immune Functions of the Appendix

Contrary to popular belief, the appendix is not a passive organ. In fact, it contains a network of neurons and is integrated into the enteric nervous system, which communicates bidirectionally with the brain through the gut–brain axis (Smith et al., 2009). You can think of it like a car, where these neurons may act as sensors within the larger enteric operation, linking local function to systemic regulation. This neural integration allows the appendix to participate in digestive control and immune signaling. Immunologically, the appendix contains lymphoid tissue that supports immune cell development and contributes to the body’s ability to recognize and respond to pathogens (Bollinger et al., 2007). One has to ponder the potential issues of removing such an important little organ.

The Appendix as a Microbial Reservoir

One of the appendix’s most important roles appears to be as a safe house for beneficial gut bacteria. The organ is lined with biofilms that protect commensal microbes during episodes of gastrointestinal distress, such as severe diarrhea or antibiotic-induced dysbiosis (Sagor et al., 2025). Once the disturbance subsides, these microbes can repopulate the colon and help restore a healthy microbiome. Reduced microbial diversity has been observed in individuals with appendicitis, which demonstrates the appendix’s connection to microbial stability (Sagor et al., 2025). Again, the removal of such an organ could be problematic for those who are getting it removed.

Clinical Implications and Shifting Surgical Practices

The traditional approach to appendicitis has been surgical removal, but mounting evidence suggests this practice has been misguided. Thankfully, recent clinical trends reflect a more conservative approach in select cases. For uncomplicated appendicitis, some hospitals now opt for antibiotic therapy, aiming to preserve the appendix’s long-term function when safe to do so. This change reflects growing recognition that the loss of the appendix may have significant downstream effects on gut health, immune function, and microbial diversity.

Looking forward, treatment paradigms will likely continue shifting away from strategies that broadly eradicate microbes and toward those that promote microbial diversity and ecological stability. Antibiotics, while often life-saving, indiscriminately destroy both pathogenic and commensal species, leaving the gut vulnerable to dysbiosis and opportunistic infections. This is particularly problematic when the appendix itself is essential for microbial recovery. By contrast, emerging approaches such as fecal microbiota transplantation (FMT) directly repopulate the gut with healthy communities, restoring resilience after disturbances. FMT has already shown remarkable success in treating recurrent Clostridioides difficile infections and is being investigated for inflammatory and metabolic conditions.

I can tell you from personal experience that when the appendix is removed, and antibiotics are given post-surgery, fecal microbiota transplantation becomes critical for restoring intestinal health. This realization is shifting priorities and creating new opportunities. Other microbial therapies are likely to follow. Advances in precision probiotics, prebiotics designed to feed specific microbial groups, and even bacteriophage therapy offer the possibility of selectively targeting pathogens while sparing or enriching beneficial organisms. In the context of appendicitis, these approaches could not only treat acute infection but also preserve or restore the appendix’s microbial reservoir, thereby maintaining its evolutionary role as a safe house for commensal bacteria.

Taken together, these innovations point toward a future in which medicine treats the appendix not as a disposable organ but as a vital component of human microbial ecology. Can you imagine a healthcare system that actually recognized the brilliance of nature? Granted, surgical removal may remain necessary in complicated or life-threatening cases, but for many patients, therapies designed to protect, preserve, and enhance microbial diversity may (hopefully) become the standard of care.

Looking even further ahead, we can probably speculate that medicine may even (someday) pursue appendix transplantation or the implantation of bioengineered appendix-like organoids. Unlike fecal microbiota transplants, which really only provide temporary restoration of diversity, a functioning appendix could serve as a permanent microbial reservoir and immune niche, continually supporting gut stability. While surgical, immunological, and microbial challenges make this speculative for now, I would argue that advances in tissue engineering and regenerative medicine suggest that restoring the appendix itself could become a frontier in ecological approaches to human health. Frankly, as someone who no longer has his appendix, I look forward to that possibility.

Diet and Microbiome Diversity

Let’s discuss the microbiome for a moment, because there seems to be some confusion on the matter. First of all, we need to understand that microbiome composition is highly responsive to diet. This is important because a diverse and balanced microbiome has been linked to better digestion, immune resilience, and overall metabolic health (Moszak et al., 2020). Don’t let internet trends sway you! While plant-based diets can support microbial richness, plenty of evidence also supports the benefits of dietary diversity, including both animal products and fruits, for fostering a resilient microbial ecosystem.

The Omnivore Advantage: Fruit–Animal Product Synergy and Appendix Health

Nature’s Intent (the true omnivore diet) combines animal products with fruit to create a nutrient profile that can support the appendix’s role in microbial preservation and recovery. Fruits supply fermentable fibers (such as pectin and inulin), polyphenols, and vitamin C, compounds known to promote the growth of beneficial bacterial genera including Bifidobacterium and Lactobacillus (Liu et al., 2021). These substrates feed the microbes housed in the appendix’s biofilms, maintaining their viability during times of stress or illness. Moreover, it seems that broader omnivorous diet composition improves parasite resistance and stress recovery, supporting the ecological value of this approach (Blubaugh et al., 2023). That’s a win in both directions.

Of course, animal products provide complementary benefits. High-quality proteins deliver amino acids such as glutamine, essential for intestinal epithelial cell function and mucosal repair (Rao & Samak, 2012). Nutrients like vitamin B12, heme iron, and zinc are critical for immune activity and microbial modulation, with zinc in particular supporting gut barrier integrity (Mao et al., 2014). Bone broth and collagen-rich meats further contribute amino acids like proline and glycine, which aid in tissue repair and gut lining stability; both are essential for sustaining the microbial habitat within the appendix.

This dietary synergy is especially important after disturbances to the gut ecosystem. For example, following antibiotic treatment or gastrointestinal infection, the appendix can reseed the colon with its stored microbial populations. Hence, a diet rich in both fruit-derived fermentable substrates and animal-derived repair nutrients can optimize this recovery process by simultaneously feeding beneficial bacteria and restoring the structural and immune environment that supports them. That seems pretty straightforward.

While direct human trials connecting an omnivore diet to improved appendix function are not yet available, it’s easy to see that converging evidence from microbiome research, nutrient–immune interactions, and appendix reservoir studies suggests a strong mechanistic plausibility. All this to say that a diet based on unprocessed animal products and fresh fruit, rather than refined or ultra-processed foods, aligns well with both microbial diversity goals and the physiological needs of the appendix.

Fermented Foods and Microbial Support

Beyond basic diet, I would also argue the importance of including fermented foods such as kefir and yogurt, because they help to increase microbial diversity and reduce inflammatory markers (Wastyk et al., 2021). Moreover, these foods are especially helpful for individuals who have already undergone an appendectomy, as they help maintain microbial balance in the absence of the appendix’s reservoir function. Of course, real, preferably homemade, kefir and yogurt are probably best.

Final Thoughts

From a health science perspective, I would say that the appendix is far from a redundant remnant of human evolution. It functions as an immune organ, a neural participant in gut–brain communication, and a protected storehouse for beneficial gut bacteria. These roles have direct implications for digestive health, immune resilience, and microbial stability. Hence, preserving the appendix when medically appropriate is preferred. Combined with a diet that supports microbial diversity (especially one that incorporates both animal products and fruits), that’s how to ensure optimal gut and overall health.

Learn more about Nature’s Intent.
Explore real kefir via Kefirlady.com

Dr. Robertson is a health researcher and educator, not a physician. The information provided here is not medical advice, a professional diagnosis, opinion, treatment, or service to you or any other individual. The information provided is for educational and anecdotal purposes only and is not a substitute for medical or professional care. You should not use the information in place of a visit, call, consultation, or the advice of your physician or other healthcare providers. Dr. Robertson is not liable or responsible for any advice, course of treatment, diagnosis, or additional information, services, or products you obtain or utilize. IF YOU BELIEVE YOU HAVE A MEDICAL EMERGENCY, YOU SHOULD IMMEDIATELY CALL 911 OR YOUR PHYSICIAN.

References

Blubaugh, C. K., Hoy, S. R., Laubmeier, A. N., Kaser, J. M., & Snyder, W. E. (2023). Omnivore diet composition alters parasite resistance and host stress recovery. Journal of Animal Ecology, 92(6), 1107–1118. https://doi.org/10.1111/1365-2656.14004

Bollinger, R. R., Barbas, A. S., Bush, E. L., Lin, S. S., & Parker, W. (2007). Biofilms in the large bowel suggest an apparent function of the human vermiform appendix. Journal of Theoretical Biology, 249(4), 826–831. https://doi.org/10.1016/j.jtbi.2007.08.032

Liu, Y., Tran, D., Rhoads, J. M., & Carroll, R. J. (2021). Dietary fiber and gut microbiome modulation in health and disease. Nutrients, 13(9), 3400. https://doi.org/10.3390/nu13093400

Mao, X., Gu, C., Ren, W., Wu, C., & Wu, G. (2014). Oxidative stress–induced diseases and dietary interventions. Amino Acids, 46(7), 1645–1665. https://doi.org/10.1007/s00726-014-1740-9

Moszak, M., Szulińska, M., & Bogdański, P. (2020). You are what you eat—The relationship between diet, microbiota, and metabolic disorders. Nutrients, 12(4), 1096. https://doi.org/10.3390/nu12041096

Rao, R., & Samak, G. (2012). Role of glutamine in protection of intestinal epithelial tight junctions. Journal of Epithelial Biology & Pharmacology, 5(Suppl 1-M7), 47–54. https://doi.org/10.2174/1875044301205010047

Sagor, M. S., Sharma, R., Zhou, Y., & Parker, W. (2025). The functional landscape of the appendix microbiome under conditions of health and disease. Gut Pathogens, 17, 38. https://doi.org/10.1186/s13099-025-00696-2

Wastyk, H. C., Fragiadakis, G. K., Perelman, D., Dahan, D., Merrill, B. D., Yu, F. B., Topf, M., Gonzalez, C. G., Van Treuren, W., Han, S., Robinson, J. L., Elias, J. E., Sonnenburg, E. D., Gardner, C. D., & Sonnenburg, J. L. (2021). Gut-microbiota-targeted diets modulate human immune status. Cell, 184(16), 4137–4153.e14. https://doi.org/10.1016/j.cell.2021.06.019