Arizona medical college study shows appendix serves a purpose

PHOENIX — Your appendix may be useful after all.

A new study from an Arizona college of osteopathic medicine shows the tiny pouch just off the digestive system is a reservoir for good gut bacteria. The tiny organ also is an important adjunct to the immune system.

“The appendix has a concentration of something called lymphoid tissue in it,” study author Dr. Heather Smith of Midwestern University in Arizona said.

“Lymphoid tissue is essentially a secondary immune tissue.”

As for the gut bacteria, she said, “During times of gastrointestinal distress, when all of the good gut bacteria gets flushed out of the system, the appendix serves as kind of a little safe house [for good gut bacteria].”

Smith is an associate professor at Midwestern’s Arizona College of Osteopathic Medicine. She’s studying the evolution of the appendix across mammals.

Smith and her team found the appendix has evolved independently in several mammal lineages (over 30 separate times) and almost never disappears from a lineage once it has appeared.

This suggests that the appendix likely serves an adaptive purpose.

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