1. Soy protein is a standout among plant proteins. It is a high-quality protein that can be compared to animal protein, but strictly speaking, its amino acid score (an indicator of protein nutritional value) is still not as high as the protein found in eggs, meat, and dairy. Therefore, the protein powder widely used in clinical practice is whey protein, not soy protein.
2. Soy products like tofu, dried tofu, yuba (tofu skin), and vegetarian chicken can be a source of calcium. However, soy products like soy milk, silken tofu, tofu pudding, yuba (tofu skin), and thousand-layer tofu contain less calcium because these latter products are not made with calcium-containing coagulants (such as nigari or gypsum).
3. The nutritional importance of soy products for vegetarians is unparalleled. Vegetarians should consume more soy products. The "Dietary Guidelines for Chinese Residents (2016)" recommends that a fully vegetarian population should consume 50~80 grams of soybeans daily (equivalent to a large block of tofu about 400 grams), while lacto-ovo vegetarians should consume 25~60 grams of soybeans (or equivalent soy products) daily, which is twice the amount for the general population.
4. Fermented soy products such as fermented tofu (stinky tofu), douchi (fermented black beans), and soybean paste are typically high-salt foods and are not on the list of recommended healthy foods. However, they do have unique advantages: they contain vitamin B12, which is not found in other plant-based foods. This is particularly important for fully vegetarians. The "Dietary Guidelines for Chinese Residents (2016)" also suggests that fully vegetarians should consume 5~10 grams of fermented soy products daily.
5. Soybeans are rich in phospholipids, especially lecithin, which is one of the two primary raw materials for producing the health supplement "lecithin" (soy lecithin). The other source of lecithin is egg yolk (egg yolk lecithin).
6. Soybeans contain various phytochemicals, including sterols, oligosaccharides, saponins, soy isoflavones (phytoestrogens), soy fiber, phytic acid, and trypsin inhibitors. These components are almost all extracted and sold as health supplements. In soy products like tofu, dried tofu, and yuba (tofu skin), most of these substances are lost and only a small amount remains. However, in products like soy milk, boiled soybeans, douchi (fermented black beans), and soybean powder, most of these substances are retained. In soybean oil, these substances are completely absent.
7. Raw soybeans are toxic. The harmful substances they contain, such as lectins, are sufficient to cause food poisoning. Fortunately, these toxic substances are destroyed after cooking, making cooked soybean products safe. Raw or undercooked soy milk is extremely dangerous, and there have been many cases of poisoning from it.
8. Soybeans have become one of the inexpensive raw materials for the food industry. Besides being used to extract soybean oil and produce health supplements, soy protein and phospholipids are widely used in various meat products, beverages, nutritional foods, snacks, and other items. It's not an exaggeration to say they are ubiquitous.
9. When we refer to soybeans, we mainly mean soybeans, black soybeans, and green soybeans. Their nutritional value is fundamentally different from that of other legumes like mung beans, red beans, lentils, fava beans, and kidney beans. The latter legumes contain a high amount of starch (over 50%) and very little fat, whereas soybeans have almost zero starch content and are rich in fat (which can be used for oil extraction).