In the last few years, two articles — one in Journal of
Theoretical Biology, the other in Journal of Evolutionary
Biology — by William Parker, a professor of surgery at Duke, and
others have argued that the function of the appendix is to
harbor bacteria. If diarrhea washes out your intestines,
bacteria safely hiddne in the appendix can repopulate them. (A
theory supported by the position of the appendix — roughly in
the middle of your intestines.) That makes perfect sense. The
connection with my umami hypothesis is that both assume that the
foreign bacteria within us are precious and endangered. (My
umami hypothesis says we need to consume plenty of bacteria to
be healthy and that our food preferences help us do so.) The
precious part is widely accepted; it’s the endangered part
that’s new. If we need bacteria so much, why should they be
endangered? We need our eyes; they aren’t endangered. My answer
is that to protect bacteria carries a cost: The most hospitable
the digestive system becomes to bacteria, the