The fermented bean curd product called tofu is reported to date back to the Chinese Han dynasty about 2000 years ago. Tofu is primarily made from soybeans, a species of legumes native to East Asia that can be picked, processed or fermented to create various forms like edamame, miso and tofu.
Known as “the cheese of Asia,” tofu undergoes processing methods similar to cheese made from animal milk. The process begins with soaking the soybeans, then crushing, boiling, and separating the mixture into pulp and milk. Ingredients that will cause the soy milk to coagulate (clump up) are added. Commonly used coagulants are salts, acids or enzymes. Much like the making of cheese, the curds and whey are separated and strained, and the curds are poured into molds where they can be shaped and pressed to release excess liquid and whey. The resulting soft molds of tofu are then cut into squares and stored in cool water.
Soybeans and their agricultural journey are big business! They are one of the top three farm products in the US (with cattle and corn) and are the world’s largest source of animal protein feed and the second largest source of vegetable oil (1)(2). And given the fact that nearly 90% of all soy in the US is NOT organic and is grown from genetically modified seeds, these potentially healthy benefits could be lost in translation. Since GMO soybeans are intentionally tolerant to pesticides, a whole lot of those are often sprayed on the growing plants. Residue left on the plants can’t be great for your palate, let alone your health!
So, if you’re looking to incorporate tofu into your diet, seek out organic products. The USDA organic standards require that, synthetic fertilizers, pesticides, sewage sludge, irradiation and genetic engineering may not be used (9) Therefore, organic tofu, which is made from non-GMO soybeans and grown without the risk of potential chemical contamination, is a better option
Mild in flavor and a good culinary vehicle for spices and sauces, tofu is often a popular meat alternative, and it has some redeeming qualities in terms of nutrition. Providing a complete source of protein containing all nine essential amino acids, soy also contains polyunsaturated fat including omega-3s, B-vitamins, iron, zinc, and antioxidants (3).
One of the major nutritional features of soy is the isoflavone content. Isoflavones are a type of polyphenol (antioxidant) found in legumes, chickpeas, fava beans, pistachios, peanuts, and other fruits and nuts. Soybeans are the richest source of isoflavones, which are known to have estrogenic properties (that is, they can have similar effects to the hormone estrogen). These can act in completely different ways depending on the individual consuming the soy! Even your specific microbiome composition can influence how soy isoflavones interact in the body (4). This means that isoflavones have the capacity to increase AND/OR decrease estrogenic activity in the body.
Is that a good thing or a bad thing? Unfortunately, we don’t really know yet—there is evidence that points both to reduced and increased cancer risk (5)(6)(7). That’s partly because your body’s response to isoflavones seems to be related to other aspects of your diet and lifestyle, as well as your genes and ancestry.
One thing you may want to know is that tofu’s isoflavone content is relatively moderate compared to several other forms of soybeans and fermented soy products like Natto or Miso.
And keep in mind that other types of beans, such as fava beans, chickpeas, kidney beans, and black beans, are also quite nutritious.
- Fast Facts About Agriculture & Food
- Straight Talk About Soy
- Soy Isoflavones
- Soy isoflavone: The multipurpose phytochemical
- Isoflavones: Anti-Inflammatory Benefit and Possible Caveats
- Biological Effect of Soy Isoflavones in the Prevention of Civilization Diseases
- Is Soy Good for You — Or Not?
- How Tofu Is Processed
- USDA Certified Organic: Understanding the Basics