SOY STORY
Over the past few years, we’ve added more soy into our diet. JoAnne makes a terrific tofu parmesan about once a month and we’ve come to enjoy meatless burgers made with soy, like the Impossible Burger. At the Thai restaurant we regularly visit, we’ve begun substituting tofu for chicken or shrimp in pad Thai and in curries. Also, at Japanese restaurants I always order a bowl of miso soup along with my sushi or baked roll. And edamame makes a great snack
Soy foods are, of course, made from soybeans. The soybean is a legume because it grows in pods containing seeds—we call them beans! Soybeans can be eaten whole or processed into various forms.
Soy Products
Whole soy products are the least processed. They include soybeans and edamame. Edamame is a preparation of immature (green) soybeans in the pod. The pods are boiled or steamed and are often served with salt and other condiments.
Soy milk and tofu are also made from whole soybeans. Soy milk is produced by soaking and grinding whole soybeans, boiling them in water and then filtering out the solids. Tofu is made by coagulating soy milk and pressing the curds into blocks.
Fermented soy products are those that have been cultured with beneficial bacteria, yeast or mold, and include soy sauce, tempeh, miso and natto.
Soy based processed foods include vegetarian meat substitutes such as Impossible Burgers. In addition many packaged foods contain soy flours, soybean oil or texturized vegetable protein made from soy.
And then there are soy supplements including soy protein isolate, which is a highly processed derivative of soy made by grinding soybeans into flakes and then extracting the oil. Soy protein isolate is in many protein powders and also added to other processed foods such as protein bars and shakes. However, supplementing your diet with soy isoflavone supplements shows no health benefits and should be avoided.
Benefits of Soy
Edamame
Soybeans are a fantastic source of high-quality protein, much more than other legumes. In fact, it’s next only to the protein we get from animal foods. Its protein is considered a complete protein because it contains all nine essential amino acids that the body cannot make and which must be obtained from your diet.
Soybeans are naturally cholesterol free and high in polyunsaturated fat (which is good for us) and low in saturated fat (which is bad for us), opposed to animal protein, which can contain high levels of saturated fat and dietary cholesterol.
Eating soy-based foods is a great way to boost your fiber intake. Fiber promotes a healthy gastrointestinal system.
Soy foods are rich in nutrients including B-vitamins, potassium, magnesium, iron, and zinc and an array of antioxidants.
Soy Controversies
Soy is unique in that it contains a high concentration of isoflavones, a type of plant estrogen that is similar in function to human estrogen but with much weaker effects.
These have been linked to better heart health and reduced risk of breast and prostate cancers. They also can help suppress osteoporosis in postmenopausal women.
However excessive soy intake may cause an imbalance in the menstrual cycle, thyroid problems, decreased sperm count, erectile dysfunction and dementia. Soy protein is also one of the main triggers of food allergies.
Conclusion
It’s clear that more studies are needed before we can determine how much the benefits of soy outweigh the possible deficits. It seems best to stay away from soy isoflavone supplements and foods made with textured vegetable protein and soy protein isolate. But it should be okay to eat whole or fermented soy foods, such as tofu, soy milk, edamame, miso and soy sauce in moderation several times per week.