# Consequences of non-Japanese inability to digest seaweed? **URL:** \ **Category:** Factual Questions\ **Created:** [January 7, 2014, 9:09am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120 "2014-01-07T09:09:53Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![CairoCarol](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cairocarol/32/3825_2.png) [@CairoCarol](https://boards.straightdope.com/u/CairoCarol)\ **Post date:** [January 7, 2014, 9:09am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/1 "2014-01-07T09:09:53Z")
Apparently non-Japanese can’t digest seaweed - see link below for details: [http://blogs.discovermagazine.com/notrocketscience/2010/04/07/gut-bacteria-in-japanese-people-borrowed-sushi-digesting-genes-from-ocean-bacteria/#.Usu\_s3lGxUM](http://blogs.discovermagazine.com/notrocketscience/2010/04/07/gut-bacteria-in-japanese-people-borrowed-sushi-digesting-genes-from-ocean-bacteria/#.Usu_s3lGxUM) I’m Caucasian and like seaweed - in fact I have an open packet of tao kae noi original crispy seaweed (laver) next to me as I type. I had always thought that seaweed was a smart choice nutrition-wise: low-calorie and high in vitamins, minerals, and antioxidants. What are the implications of not being able to digest seaweed like a Japanese? Specifically: [ul] [li]Should I eat more seaweed if I’m interested in weight control, on the theory that I won’t be able to digest the stuff and therefore I’ll feel sated without by body actually getting any caloric value?[/li][li]Should I NOT eat more seaweed, because it will give me indigestion? (I’ve never noticed this happening, but it’s possible that it has, and I simply didn’t identify the seaweed as the source of occasional gastric discomfort)[/li][li]Should I assume I’m not getting any vitamins/minerals/antioxidants out of the seaweed I eat, and focus on foods like blueberries, black rice, dark grapes, etc. if I want to jump on the “black food is good for you” bandwagon?[/li][/ul] Finally, I wonder if this digestion thing applies to all seaweed or just nori. I love wakami, which I associate with that slightly translucent, slightly rubbery green seaweed, and the pinkish stuff that is sometimes part of a seaweed salad is pretty good too. ---
**Author:** ![The\_Niply\_Elder](https://avatars.discourse-cdn.com/v4/letter/t/8e8cbc/32.png) [@The\_Niply\_Elder](https://boards.straightdope.com/u/The_Niply_Elder)\ **Post date:** [January 7, 2014, 9:21am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/2 "2014-01-07T09:21:14Z")
The study is based on 13 Japanese subjects and 18 North American subjects. The study is so small as to render it statistically insignificant. Fortunately you can keep munching away at thise seaweed crackers as much as you want, and you’ll get nutrients out of them as much as any Homo sapiens sapiens might. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [January 7, 2014, 11:18am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/3 "2014-01-07T11:18:57Z")
Read the article carefully. First, it’s not talking about anything inside the genes of Japanese or Americans. It’s talking about the intestinal bacteria typically found in Japanese or Americans. Your intestinal bacteria don’t come from your genes. They come from everything you’ve digested over your life. So even if this article is accurate and even if you currently don’t have any of the particular bacteria that the article is talking about, if you emigrated to Japan and spent enough time eating the food there, you would presumably soon acquire these bacteria. As The Niply Elder pointed out, this study has a very small number of subjects. Furthermore, the article is written in a confusing way. It’s not clear to me why the researcher picked these particular intestinal bacteria to study. Are these bacteria the only ones that could digest seaweed and convert it to material that humans can use for nutrition, or are they just a small sample of such bacteria? Perhaps there are other bacteria that will digest seaweed properly, and perhaps they are found in non-Japanese intestines frequently. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [January 7, 2014, 11:46am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/4 "2014-01-07T11:46:55Z")
Given that the Japanese are not the only people who have historically eaten seaweed I very, very much doubt that everyone else finds them “undigestible”. The Irish have long eaten carrageenan (note the name - not Japanese at all) and dulse is also of European origin. If you like seaweed and it doesn’t cause gastrointestinal upset keep eating it. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [January 7, 2014, 12:01pm UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/5 "2014-01-07T12:01:58Z")
They tested for Zobellia , as used to make " Nori ". Fermented seaweed. (Like sauerkraut is fermented cabbage, or yoghurt is fermented cream.) So they found Zobellia in people who ate Nori regularly, but not in people who do not. The article explains how being exposed to different bacteria may leave just the plasmids of some of them… But it could also conclude that the bacteria on our food does survive the stomach and small intestine ! ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [January 7, 2014, 12:32pm UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/6 "2014-01-07T12:32:09Z")
There’s no question that some bacteria survives the stomach and the intestine. That’s how our intestines get their resident bacteria. The reason that our intestines are lined with bacteria is that over our lifetimes we accumulate the bacteria every time we eat. And you have to have that bacteria. People without it get sick. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 7, 2014, 4:19pm UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/7 "2014-01-07T16:19:31Z")
I’ve heard anecdotal reports that eating seaweed can improve digestion in Westerners. One of my vegetarian aunts includes seaweed in her bean soup recipe, with the explanation that “it keeps the farts away”. ---
**Author:** ![JpnDude](https://avatars.discourse-cdn.com/v4/letter/j/838e76/32.png) [@JpnDude](https://boards.straightdope.com/u/JpnDude)\ **Post date:** [January 8, 2014, 2:00am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/8 "2014-01-08T02:00:48Z")
> [@Chronos](#): > > I’ve heard anecdotal reports that eating seaweed can improve digestion in Westerners. One of my vegetarian aunts includes seaweed in her bean soup recipe, with the explanation that “it keeps the farts away”. That’s funny. I eat wakame with miso soup as part of my daily breakfast. On days that I have a side salad with [daikon](http://en.wikipedia.org/wiki/Daikon), I have a day full of gas (burping and farting). 😛 ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [January 8, 2014, 5:47am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/9 "2014-01-08T05:47:23Z")
Have you noticed tao kae noi seaweed has a fried version and a baked version? ---
**Author:** ![citizenzen](https://avatars.discourse-cdn.com/v4/letter/c/a8b319/32.png) [@citizenzen](https://boards.straightdope.com/u/citizenzen)\ **Post date:** [January 8, 2014, 5:52am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/10 "2014-01-08T05:52:31Z")
I often eat the seaweed salad and seaweed wrapped sushi at my favorite Japanese restaurant. I have never noticed any change to my digestion … good or bad. ---
**Author:** ![jovan](https://avatars.discourse-cdn.com/v4/letter/j/0ea827/32.png) [@jovan](https://boards.straightdope.com/u/jovan)\ **Post date:** [January 8, 2014, 6:12am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/11 "2014-01-08T06:12:04Z")
> [@Isilder](#): > > They tested for Zobellia , as used to make " Nori ". Fermented seaweed. (Like sauerkraut is fermented cabbage, or yoghurt is fermented cream.) That’s wrong. Nori is not fermented. There’s a vegemite-like [fermented nori product](http://www.nori-marutaka.co.jp/hakkou.html) but it’s hardly mainstream. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [January 8, 2014, 3:41pm UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/12 "2014-01-08T15:41:07Z")
Please read the article that’s linked to in the OP carefully. It says nothing whatsoever about non-Japanese people having digestive problems (i.e., gas or whatever) when eating seaweed. What it’s talking about is an inability to convert the seaweed while in the intestinal tract to nutritional useful material. This would probably simply mean that the seaweed goes all the way through the tract and is excreted without being converted to anything nutritionally useful. That doesn’t imply any build-up of gas. ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [January 9, 2014, 12:33am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/13 "2014-01-09T00:33:14Z")
Well, now! Wendell directed us back to the original link, which I should have clicked on in the first place. Thanks, Wendell. The article suggests that bacteria, _Zobellia galactivorans,_ or genes from them, on the seaweed make it into the gut of Japanese people, and helps them take nutrients from seaweed. With all the hubbub over probiotics, it would seem that Zobellia could be encased in an enteric coating to protect it from the germicidal stomach acid, to allow people of any nationality get nutrients from seaweed. By extension, perhaps the bacteria from termite guts could be implanted in ours, to allow us to live on cellulose, as the termites do. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [January 9, 2014, 3:09am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/14 "2014-01-09T03:09:05Z")
Read a bit more carefully. It is not clear when this transfer of the plasmid to digest these particular seaweed carbohydrates was transfered from the algae to the gut bacterium creating the symbiont. It is however not something that happens all that easily. > [@](#): > > it’s not clear how long these marine genes have been living inside the bowels of the Japanese. People might only gain the genes after eating lots and lots of sushi but Hehemann has some evidence that they could be passed down from parent to child. One of the people he studied was an unweaned baby girl, who had clearly never eaten a mouthful of sushi in her life. And yet, her gut bacteria had a porphyranase gene, just as her mother’s did. Also noted: > [@](#): > > “Today, sushi is prepared with roasted nori and the chance of making contact with marine bacteria is low,” she said. The project’s other leader, Gurvan Michel, concurs. He notes that of all the gut bacteria from the Japanese volunteers, only B.plebeius as acquired the porphyranase enzymes. “This horizontal gene transfer remains a rare event,” he says. Gas btw would only result if an individual HAD resident bacteria than could digest (ferment) the carbohydrate. In particular ones that produced gases as a by-product. (Some do more than others.) Indeed without the specific bacteria they’d just pass through inert. ---
**Author:** ![Leaper](https://avatars.discourse-cdn.com/v4/letter/l/4bbf92/32.png) [@Leaper](https://boards.straightdope.com/u/Leaper)\ **Post date:** [January 9, 2014, 3:12am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/15 "2014-01-09T03:12:19Z")
This thread inspired a sci-fi humor novel idea where the Earth’s climate’s changed so much that the most convenient and cheapest available food is seaweed, so the Japanese basically rule the globe. 😃 ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [January 9, 2014, 5:19am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/16 "2014-01-09T05:19:13Z")
May not be related but during the height of Japan, Inc. the Japanese brought national differentiation to ridiculous heights, mainly to block the entry of foreign-made products into the local market. US beef was regulated because the Japanese had a very delicate digestive system. French ski equipment were not allowed because the snow was different in Japan. ---
**Author:** ![Jragon](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Post date:** [January 9, 2014, 5:24am UTC](https://boards.straightdope.com/t/consequences-of-non-japanese-inability-to-digest-seaweed/678120/17 "2014-01-09T05:24:55Z")
> [@the\_diego](#): > > May not be related but during the height of Japan, Inc. the Japanese brought national differentiation to ridiculous heights, mainly to block the entry of foreign-made products into the local market. US beef was regulated because the Japanese had a very delicate digestive system. French ski equipment were not allowed because the snow was different in Japan. In certain corners silly levels of national/racial essentialism are still bubbling around, albeit much less maliciously. I’ve had friends who live in rural corners be politely kicked out of stores because “foreigners don’t like the kind of stuff they sell there.” Even their friends can sometimes be stymied that an American earnestly likes some type of Japanese candy or whatever. :rolleyes: