The Comforts of the Umami Hypothesis
What a difference an idea makes. A few weeks ago I came up with the idea that evolution shaped us to like umami taste, sour taste, and complex flavors so that we will eat more harmless-bacteria-laden food, which improves immune function. (I pompously call this the umami hypothesis.) It seemed so likely to be true that I started eating more fermented foods: miso, kimchi, yogurt, buttermilk, smelly cheese, and wine. To avoid stomach cancer and high blood pressure, I later cut back on miso, kimchi, and smelly cheese.
There have been other changes, too:
- After buying meat or fish, I don’t try to get home quickly to put it in the fridge
- I don’t worry that eggs have been in the fridge for 3 weeks
- When buying eggs and other perishables, I don’t try to get the freshest
- I don’t worry about leaving milk out
Bacteria and viruses from other humans pose a threat. This is why we find fecal matter so offensive. It’s why hand-washing by doctors matters. But I believe plant-grown and dirt-grown bacteria are harmless because the substrates are so different than conditions inside our bodies. As for meat-, fish-, and dairy-grown bacteria, I don’t think they are very dangerous. Has anyone gotten food poisoning from yogurt? I keep in mind how much stinky fish the Eskimos ate. Maybe I should do some controlled rotting experiments — leave meat at room temperature for varying lengths of time before cooking and eating it.
February 13th, 2009 at 3:14 am
I’m trying to brainstorm fermented foods that are neither potentially harmful in the ways you’ve identified nor in my personal case. I have a casein allergy, so no yogurt. (at the moment!) Asian Flush syndrome makes wine inconvenient– a small amount makes me turn red and my head pound.
Probiotics are something I haven’t been able to investigate enough. All the widely available and affordable live culture products seem to be yogurt-based.
What you say about bacteria in different ecologies makes sense. My naive generalization would go like this: the strains that are usually harmful are ones that thrive in living animal tissue, whether parasitic or symbiotic. The bacteria that do well in dirt, plants, or decaying matter probably won’t pose as much a threat to live humans. And then there are bacteria that seem to be wholly beneficial. I am saying this with very little knowledge of microbiology, of course, but this would be my first guess.
February 13th, 2009 at 5:29 am
Ah, Ignore my rant on different substrates of bacteria. I didn’t realized* you had covered that. I’m glad I wasn’t too far off, though.
*For some reason the browser on my phone (where I was reading this before) cut out a chunk of the last paragraph, so the post ended with “dirt-grown bacteria are harmless…” I was reading it through Google Reader for mobile, which sometimes does weird things with webpages.
February 13th, 2009 at 6:25 am
“unami” –> “umami”
February 13th, 2009 at 8:16 am
Seth, could you comment a bit more about the risks of miso, kimchi, and smelly cheese? (Re: “To avoid stomach cancer and high blood pressure, I later cut back on miso, kimchi, and smelly cheese.”) Thanks!
Cheers,
Tom
February 13th, 2009 at 2:12 pm
Stomach cancer is high in Japan and South Korea, where lots of miso and kimchi is eaten. Miso and cheese are high in salt, which raises blood pressure. After I started eating lots of miso and cheese my blood pressure appeared to go up about 10 points and when I cut back it went down about 10 points. The causality isn’t as clear as that might sound but that’s what happened.
February 14th, 2009 at 9:53 am
OOPS! (unami rather than umami). Thanks, Aaron.
February 14th, 2009 at 11:06 am
Seth, I very much resonate with your umami hypothesis and tend to crave those kinds of foods. Just wanted to add wild mushrooms to your hypothesis. They have a wide variety of unami flavors and many are well documented as being amazing for the immune system. If you would be interested in experimenting with them, I would be happy to send you some dried mushrooms or fresh when they are in season.
Also, there are lots of good naturally fermented vegetables available at health food stores, and it is pretty simple to ferment your own. Nutritional yeast and brewers yeast, kombucha (a fermented tea drink from microorganisms), rejuvelac (a sprouted grain drink) might be other good things to try. In addition to the rejuvelac, I think Ann Wigmore would make fermented cheeses out of sprouted nuts. I also love umeboshi plums but they are really salty. Bee pollen is naturally fermented with bee saliva, as well as raw honey.
February 16th, 2009 at 12:20 pm
[...] The Comforts of the Umami Hypothesis [...]
February 19th, 2009 at 9:37 pm
aged cheeses can raise blood pressure in some people, due to the tyramine content. so, ironically, can aged meats.
from wiki:
Tyramine is an amine which causes elevated blood pressure and tachycardia by displacing norepinephrine from storage vesicles. Tyramine is generally produced by decarboxylation of the amino acid tyrosine during fermentation of food products. All protein-rich foods which have been matured will contain more tyramine depending on the temperature and how long they have been stored. Properly refrigerated foods will not be affected.
February 19th, 2009 at 10:09 pm
Kathy, I didn’t know that. Thanks. My blood pressure did go down after I stopped eating the aged cheese.
February 20th, 2009 at 9:23 am
Not just high BP. Some people get migraine headaches from tyramine foods – aged cheese, wine, processed meats, and a lot of fermented foods. YMMV.
February 20th, 2009 at 9:26 am
Which cheeses are considered stinky?
April 28th, 2009 at 12:18 am
[...] Anyway one of his recent theories is the Umami Hypothesis. the idea that evolution shaped us to like umami taste, sour taste, and complex flavors so that we will eat more harmless-bacteria-laden food, which improves immune function. (I pompously call this the umami hypothesis.) It seemed so likely to be true that I started eating more fermented foods: miso, kimchi, yogurt, buttermilk, smelly cheese, and wine. To avoid stomach cancer and high blood pressure, I later cut back on miso, kimchi, and smelly cheese. [...]
July 27th, 2009 at 6:51 pm
[...] Seth Roberts has proposed an interesting hypothesis, that humans like complex tastes (umami) because we evolved to like the taste of bacteria in food. He believes that bacteria from natural pickling is harmless, and actually improves our immune function. As reported in Conditioning Research, Roberts points out that explorer Vihjalmur Stefansson reported that Eskimos ate lots of bacteria fermented fish, which he also grew to enjoy. Supporting this theory, Conditioning Research also tells of University of Michigan paleontologist, Dan Fisher, who butchered a draft horse and cached the meat in a stock pond.  The lactobacilli in the water pickled the meat, which it emitted a slightly sour odor that put off scavengers when it floated to the surface. Fisher cut and ate the meat from February until summer to prove its safety, showing how hunter gatherers might have once stored their large animal kills. As I blogged in an earlier post, fermented foods also are known to be good sources of vitamin K2. Social bookmarksSubscribeBlinklistBloglinesBlogmarksDiggdel.icio.usFacebookFurlMa.gnoliaNewsVineRedditStumbleUponTechnorati [...]