I had my appendix removed when I was a child because the doctor told my mother it was a useless organ that might someday burst and cause horrible problems. After generations of children had their appendices removed for no reason, researchers have found that perhaps it may have an important function.
The lymphatic tissue in the appendix is different from lymphatic tissue in other parts of your gut in that it may stimulate your immunity to grow beneficial healthful bacteria there (Nature Immunology, 2016;17:179–186). The authors theorize that appendix serves as a safe storage area that can help to replenish your colon with beneficial bacteria to replace those that are lost when you take a course of antibiotics or when harmful bacteria invade your colon and cause diarrhea. Today researchers are trying to mimic what the appendix can do by treating people with fecal transplants to give them other people's good bacteria. This experimental technique is being tried as a possible treatment for many different diseases.
Heather F. Smith at Midwestern University Arizona College of Osteopathic Medicine reviewed the appendices in 533 different animal species. She mapped the data onto a "genetic tree" to follow the appendix as it evolved through many different species of mammals (Comptes Rendus Palevol, 2017;16(1):39). By comparing mammals that have an appendix with those that don't, she was able to show that:
• the appendix evolved independently in several mammal lineages,
• the appendix evolved in more than 30 different lineages,
• the appendix never disappears from a lineage once it has appeared, and
• animals with tapered or spiral-shaped ceca (the part of the colon around the appendix) also were the ones most likely to have an appendix. Therefore the appendix evolved at the same time that the area around it also became narrower and longer.
Her research suggests that appendices serve an adaptive purpose that is not determined just by diet or environmental factors.
Your Colon is Full of 30 Billion Good and Bad Bacteria
Good bacteria are those that colonize your colon but do not try to penetrate its lining to get into your bloodstream. The good bacteria break down food to release nutrients so they can be absorbed into your bloodstream. Bad bacteria try to invade the inner lining of your colon and get into your bloodstream, which stimulates your immune system and causes it to be active all the time. This is called inflammation that can cause diseases such as heart attacks, strokes, diabetes, obesity, allergies, auto immune diseases and certain cancers (Expert Rev Anti Infect Ther. Apr, 2010;8(4):435–454).
The appendix has far more lymphoid tissue than the rest of the first part of the colon (Nature Immunology, 2016;17:179–186). This suggests that the appendix has greater immunological activity than the rest of your colon to protect you from harmful bacteria, and could be better able than the rest of the colon to get rid of the bad bacteria that try to get into your bloodstream. Therefore the appendix most likely serves as a "safe house" for helpful gut bacteria. A diet that includes lots of leafy green vegetables has been shown to increase colon lymphoid tissue, reducing symptoms of inflammation in asthma, inflammatory bowel disease and psoriasis (Expert Rev Anti Infect Ther. Apr, 2010;8(4):435–454).
• A healthy appendix should never be removed just because it is there
• Your appendix may help to protect you from disease by storing healthful bacteria
• If you lose many of your good colon bacteria from an infection or from taking antibiotics, some of the good healthful bacteria are stored in your appendix. When you stop taking the antibiotic or when your infection is cured, the good bacteria move quickly from your appendix into the rest of your intestines to replace the ones that were lost.