Thursday, September 20, 2007

Intestinal Fortitude

When you first arrive in Japan, you are exposed to a lot of facts which may be myths and myths that may be facts. The average foreigner is highly suspicious of most of the little tidbits of information tossed her way. The main reason for this is that, by and large, we're taught in our home countries that we're all the same under our skin and a human is a human is a human. The Japanese, on the other hand, are taught that they are different and unique from other humans and readily accept that there are physiological variations based on ethnic background.

There is some factual data in regards to medical conditions and differences which are clearly ethnically-based so the notion that we may be constructed differently isn't that absurd. There are a lot of examples but a few obvious ones are Sickle Cell disease which mainly affects people descended from or born in sub-Saharan areas and Tay Sachs disease which mainly affects Jewish people. If diseases and certain physical attributes can "discriminate" based on ethnicity, why can't internal biology?

One commonly-mentioned and much disbelieved myth (or fact) is that the Japanese have much longer intestines than those from western cultures. This notion has been used to explain why Japanese people shouldn't consume certain foreign foods. Most foreigners scoff or react incredulously when they are presented with this belief. The credibility of the notion isn't helped by the fact that Japanese people rarely are able to explain why this should be and that there is no readily accessible medical data in foreign languages to support the idea. Some of the Japanese people I've spoken to have stated that such data exists but only in Japanese and only in medical journals. Last night, I got a rudimentary explanation from a student for the first time and did some research into this claim based on what she told me.

One can attempt to view this (bowel length difference) idea objectively without hard evidence and speculate on its feasibility based on related information. Mainly, one can look at the animal world and how intestinal length relates to dietary habits. Herbivores are known to have much longer digestive tracts than carnivores. The reason for this is that they need the added length to break down the vegetable matter they consume in order to extract the nutrients. Carnivores have shorter intestines to allow them to digest meat more rapidly before it deteriorates in their bodies and causes illness.

All of the information regarding herbivores and carnivores in the animal kingdom is absolute fact. However, people are omnivorous (but actually closer to being herbivores than carnivores in terms of their digestive systems). The Japanese contend that they have longer intestines because they are descendants of people whose diets were skewed much more toward a vegetable-based diet than western people who are the descendants of people who included much more meat in their diets. As a theory, this isn't too hard to believe since the modern Japanese diet still contains a lot of soy-based proteins, seafood, and vegetables.

The possibility that longer bowel length is a fact among Japanese (or other Asian) people compared to western people opens up a lot of discussion and theory about how their health may differ compared to westerners. It's been speculated that their slim physiques may be related to longer intestines as digestive processes are metabolically intense. It's also possible that it can increase longevity if more nutrients are extracted from vegetables that are consumed.

The only real question is whether or not someone has ever done comparative autopsies on a statistically valid number of bodies and measured intestinal length and proven this theory. Somehow, I doubt anyone has because the truth is that proving it isn't all that important unless you're Japanese and have health concerns related to your dietary habits. Since most Japanese people already accept this theory as fact, they've already incorporated it into their mindset in regards to health maintenance.

I'm not suggesting that this "myth" is true but rather that we should be a bit more open to the possibility that some of the notions which initially strike us as preposterous may not be so silly after all. Even if they are actually not true, there may be at least some sound logic behind them which make them sound reasonable to the Japanese who believe such ideas.

12 comments:

tornados28 said...

Even if there are medical studies only in Japanese, they need to be referenced by those who claim this. Things like this need to be based on factual scientific data. For japanese to just state it as fact or claim that there are medical studies only in Japanese is not good enough. Until then I will be skeptical.

terrance said...

hrmm, i wonder how much truth there is to that. One thing I did notice while I was in Japan over the summer was that no matter how much I ate, i was always hungry. Now you could attribute it to having a very american appetite, but I'm pretty sure I was eating the exact same amount I would be eating in the states. Any thoughts?

Kanagawa G said...

I read a lot of "nihonjinron" while I was studying for my MA and the longer intestine theory was often attributed as the pseudo-scientific rationale behind higher import tariffs on foreign meat. The Japanese have also claimed that Japanese snow is "different" therefore levying higher tariffs on French skis, which caused some political and economical backlash between the two nations.

Japan is still trying to cling to the "one-race, one-culture, one-language" theory (another recent media gaffe by then Foreign Minister Taro Aso) when such is not the case. There are many ethnic and native groups in Japan as well as cultural and linguistic subsets. Homogeneity is an illusion, and a poor one at that.

Shari said...

tornados28 and KanagawaG: I'm inclined to agree. However, at least this one isn't as stupid as it sounds on the surface in terms of the rationale behind this particular belief. One of my students is married to a doctor who does research into gastrointestinal diseases and I'm going to ask her to ask him about studies next time we meet.

While I can be somewhat open-minded about physiological differences based on the pool of people being somewhat limited, I can't see any logic behind a difference in snow in Japan though I'm not a meterorologist and it's not the sort of thing I'm in a position to analyze beyond noting that snow in humid areas is heavier than snow in drier areas.

terrance: I'm not sure. It's possible that the heat and humidity made you burn calories faster or the food, which you may not have been accustomed to, didn't sate you. If you walked around more, it could be you just burned more calories everyday.

Thanks to all for taking the time to comment!

Miko said...

I guess my intestines are not long, not short, but somewhere in between, tee hee!

As an experiment, I tried telling people that my blood type was "C" and that only gaijin have this type. Quite a few Japanese believed me! They do seem gullible at times.

Shari said...

Hi, Miko, and thanks for your comment. While I'm sure some of your students (who were ignorant or uncertain of blood types) believed you, it's also possible some people just chose not to openly say they felt you were wrong. Japanese people will often pretend you're right because they don't want to embarrass you by pointing out you're mistaken. In this tatamae and honne culture, I can never be sure of the genuineness of any reaction, unfortunately.

Many thanks for your comment! Sometimes I wish I had your sense of "play" with students when I hear about what you're up to!

Kanagawa G said...

I did some quick research and found that the "longer intestine" theory was first publicized in 1987 then Agriculture Minister Tsutomu Hata as a reason that Japan was unable to allow imports of foreign beef. He was forced to step down amid the resulting international ridicule and Japan started importing foreign beef.

Hata started out as a bus driver for Odakyu and later rose to the position of Prime Minister, albeit only for a few weeks. He decided to leave office rather than face a no-confidence vote.

The funny thing about intestines is that they hve no set length- the keep expanding and contracting during the digestion process.

Shari said...

I've always felt that, regardless of the facts one way or another, using biological differences as an excuse for avoiding foreign imports has been a joke. Even if you accept that Japanese (or other Asians) have longer intestines, that only affects overall dietary concerns, not geographically specific ones. Meat is meat and if they can't eat it, they can't eat Japanese beef in addition to western beef.

Ironically, your last statement about length changing leads (again, theoretical) credence to the idea that Japanese people may have longer bowels if they are constantly consuming vegetable-based foods more than people in other countries. If the length changes "as needed" depending on diet, then that'd fit as one might expect an alteration with a consistently more vegetable-based diet.

Mind you, I haven't done research and I have no idea if human intestines alter in size or length for any appreciable amount of time based on diet. A quick search indicates that primates do indeed experience such changes based on diet. Whether or not one chooses to infer such things about humans based on primate data is a matter of personal opinion/choice.

Kanagawa G said...

I meant that length changes constantly in all people throughout the day much like your heart rate goes up when you run and returns to normal during rest.

From an evolutionary standpoint, the various "races" (wince) have not been separated long enough to make adaptions such as longer intestines.

Shari said...

I'm with you on the entire "races" notion. You'll notice I assiduously avoid classifying differences as "racial" or calling different people different"races" and always say "ethnicity". I figure the human race is all one entire (same) race with variations in genetic tendencies and physical appearance.

tornados28 said...

My wife's poos are definately longer than mine though so maybe there is truth to the theory.

Patrick said...

This topic just came up in a conversation with my Japanese college-roommate. There doesn't seem to be much in the way of decisive writing about it on the internet, but the foundation of the poor kid's beliefs has been shaken.

Japanese people don't just accept this as fact, but rather it is something they learn from a very young age. It's not a question of whether this is true, it just goes along with things like 'plants need water.' It's (I guess) completely undisputed on the inside of their culture.

So maybe there isn't any real scientific evidence pointing to this conclusion, but is there any pointing to the contrary? It seems like this is just our collective "word" against theirs. (Since we believe everybody is same on the inside, or something to that effect.) It just needs hard research.