Scientists think they’ve come up with a good explanation for the appendix: it’s back-up storage of your good digestive bacteria, so that when you get sick (really, really sick) you can rebuild those essential colonies.
Living in the first world with humans all around us, there are other places to get probiotics, so our appendix is less necessary. They think that’s why we have higher rates of appendicitis (when your appendix gets infected and swells until it bursts)—our better health means we aren’t using that backup colony.
One part of the theory I disagree with: I suspect there are many first world denizens who end up needing their appendixes. Antibiotics and other treatments can kill off your good bacteria. Many people still have H. Pylori infections (so their probiotic colonies are probably not up to snuff). While the average person probably doesn’t need their appendix, anyone who’s been sick probably does, and that could be a former average person.
So if you have had your appendix removed, that means you don’t have your natural safety net. While being exposed to other people and populated places will help your body come into contact with those good colonies again, you should still be actively supporting yourself, using first world resources to help rebuild your probiotic colonies.
Appendix or not, try and eat a good source of probiotics every day. Some pickled foods (kimchi or homemade pickles!), yogurt, and other yogurt like foods are the most common sources.
If you can’t get it daily, then supplement. Whether you’re on a special diet or just hate the taste of probiotic foods, a probiotic supplement can provide a diverse amount of probiotic colonies (read the label—not all brands have the same diversity and number of probiotics!).
What do you think of this theory of the appendix?