| Just How Much Soy Did Asians Eat?
In short, not that much, and contrary to what the
industry may claim soy has never been a staple in Asia. A study of the
history of soy use in Asia shows that the poor used it during times of
extreme food shortage, and only then the soybeans were carefully prepared
(e.g. by lengthy fermentation) to destroy the soy toxins. Yes, the Asians
understood soy all right!
Many vegetarians in the USA, and Europe and
Australia would think nothing of consuming 8 ounces (about 220 grams) of
tofu and a couple of glasses of soy milk per day, two or three times a week.
But this is well in excess of what Asians typically consume; they generally
use small portions of soy to complement their meal. It should also be noted
that soy is not the main source of dietary protein and that a regime of
calcium-set tofu and soymilk bears little resemblance to the soy consumed
traditionally in Asia.
Perhaps the best survey of what types/quantities of
soy eaten in Asia comes from data from a validated, semi quantitative food
frequency questionnaire that surveyed 1242 men and 3596 women who
participated in an annual health check-up program in Takayama City, Japan.
This survey identified that the soy products consumed were tofu (plain,
fried, deep-fried, or dried), miso, fermented soybeans, soymilk, and boiled
soybeans. The estimated amount of soy protein consumed from these sources
was 8.00 ± 4.95 g/day for men and 6.88 ± 4.06 g/day for women (Nagata C,
Takatsuka N, Kurisu Y, Shimizu H; J Nutr 1998, 128:209-13).
According to KC Chang, editor of Food in Chinese
Culture, the total caloric intake due to soy in the Chinese diet in the
1930's was only 1.5%, compared with 65% for pork. For more information on
the traditional use of soy products, contact the Price Pottenger Nutrition
Foundation.
The chief concern we have about the consumption of
large amounts of soy is that there is a risk of mega-dosing on isoflavones.
If soy consumers follow the advice of Protein Technologies International
(manufacturers of isolated soy protein) and consume 100 grams of soy protein
per day, their daily genistein intake could easily exceed 200 milligrams per
day. This level of genistein intake should definitely be avoided. For
comparison, it should be noted that Japanese males consume, on average, less
than 10 milligrams of genistein per day (Fukutake M, Takahashi M, Ishida K,
Kawamura H, Sugimura T, Wakabayashi K; Food Chem Toxicol 1996, 34:457-61).
What about the
traditional use of soy in infant feeding?
Ever heard the industry line that 'soy formulas must
be safe because Asian infants have been eating soy for centuries'? Just
another piece of false advertising, a little like the claims that 'soy
formulas are better than breast milk' that many parents that have fed soy
formulas testify to. And to set the record straight, soy was seldom used in
infant feeding in Asia.
Ernest Tso is credited with the development of the
first soymilk diet that was able to sustain an infant for the first eight
months of life. Writing in the Chinese Journal of Physiology in 1928, Tso
noted that soybean milk is a native food used in certain parts of the
country as a morning beverage but it is little used as part of the diet for
children. Its nutritive properties as a food for young infants are
practically unknown.
Eight years later, Tso's comments were still valid.
Writing in the 1930's, Dr RA Guy of the Department of Public Health of the
Peiping Union Medical College found it 'pertinent to note that we have never
found soybean milk naturally used by Peiping women to feed their children.
This beverage is not made in the home in Peiping, but is sold by street
vendors, as a hot, very weak solution of soybean protein and is usually
drunk by old people in place of tea. The milk, as reinforced for the feeding
of young infants, is rather tedious and difficult to prepare. As dispensed
recently by the various health stations, it is in demand, but is just as
artificial in this community as cow's milk' (Guy RA. Chinese Med J. 1936;
50:434-442).
In a later publication, Guy reported on the use of
soybean milk as a food for infants. The whole purpose of this report was to
comment on the possible use of soymilk to address the problem of feeding
those infants without sufficient maternal milk in a country where cow's milk
was not native. He again noted that although a weak soy milk or 'tofu chiang'
was 'sold hot in Peking by street vendors and was taken by old people in
place of tea', that 'contrary to Western notions' it was not usual to feed
soy milk to infants (Guy RA and Yeh KS. Chinese Med J. 1938; 54:1-30).
It seems those same Western notions that made Asians
out to be greater soy consumers than they were are still prevalent. Why is
that? Asia is a huge market for the soy industry and the soy industry
efforts to convince Asians that their ancestors ate much more soy than they
actually did are purely profit driven. We view the attempts of the soy
industry to re-write the history books with the contempt it deserves.
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