Just How Much Soy DidAsians Eat?
In short, not that much, and contrary to what theindustry may claim soy has never been a staple in Asia. A study of thehistory of soy use in Asia shows that the poor used it during times ofextreme food shortage, and only then the soybeans were carefully prepared(e.g. by lengthy fermentation) to destroy the soy toxins. Yes, the Asiansunderstood soy all right!
Many vegetarians in the USA, and Europe and Australiawould think nothing of consuming 8 ounces (about 220 grams) of tofu anda couple of glasses of soy milk per day, two or three times a week. Butthis is well in excess of what Asians typically consume; they generallyuse small portions of soy to complement their meal. It should also benoted that soy is not the main source of dietary protein and that a regimeof calcium-set tofu and soymilk bears little resemblance to the soy consumedtraditionally in Asia.
Perhaps the best survey of what types/quantitiesof soy eaten in Asia comes from data from a validated, semi quantitativefood frequency questionnaire that surveyed 1242 men and 3596 women whoparticipated 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 boiledsoybeans. The estimated amount of soy protein consumed from these sourceswas 8.00 ± 4.95 g/day for men and 6.88 ± 4.06 g/day forwomen (Nagata C, Takatsuka N, Kurisu Y, Shimizu H; J Nutr 1998, 128:209-13).
According to KC Chang, editor of Food in ChineseCulture, the total caloric intake due to soy in the Chinese diet in the1930's was only 1.5%, compared with 65% for pork. For more informationon the traditional use of soy products, contact the Price Pottenger NutritionFoundation.
The chief concern we have about the consumptionof 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 proteinper day, their daily genistein intake could easily exceed 200 milligramsper 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 traditionaluse of soy in infant feeding?
Ever heard the industry line that 'soy formulasmust 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 havefed soy formulas testify to. And to set the record straight, soy was seldomused in infant feeding in Asia.
Ernest Tso is credited with the development of thefirst soymilk diet that was able to sustain an infant for the first eightmonths of life. Writing in the Chinese Journal of Physiology in 1928,Tso noted that soybean milk is a native food used in certain parts ofthe country as a morning beverage but it is little used as part of thediet for children. Its nutritive properties as a food for young infantsare 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 ofthe Peiping Union Medical College found it 'pertinent to note that wehave never found soybean milk naturally used by Peiping women to feedtheir children. This beverage is not made in the home in Peiping, butis sold by street vendors, as a hot, very weak solution of soybean proteinand is usually drunk by old people in place of tea. The milk, as reinforcedfor 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. ChineseMed J. 1936; 50:434-442).
In a later publication, Guy reported on the useof soybean milk as a food for infants. The whole purpose of this reportwas to comment on the possible use of soymilk to address the problem offeeding those infants without sufficient maternal milk in a country wherecow's milk was not native. He again noted that although a weak soy milkor 'tofu chiang' was 'sold hot in Peking by street vendors and was takenby old people in place of tea', that 'contrary to Western notions' itwas not usual to feed soy milk to infants (Guy RA and Yeh KS. ChineseMed J. 1938; 54:1-30).
It seems those same Western notions that made Asiansout to be greater soy consumers than they were are still prevalent. Whyis that? Asia is a huge market for the soy industry and the soy industryefforts to convince Asians that their ancestors ate much more soy thanthey actually did are purely profit driven. We view the attempts of thesoy industry to re-write the history books with the contempt it deserves.