Extremely versatile and high in nutrients, soy foods such as soymilk, tofu, miso, and tempeh are all derived from the soybean, a legume that was first cultivated in northern China about 3,000 years ago. The Chinese honored soybeans as one of the five sacred grains essential to the existence of civilization—the others were rice, barley, wheat, and millet. They considered the soybean to be both a food and a medicine.
While soybeans were widely eaten in many parts of the world, it wasn’t until 1765 that they were first planted in the United States. They served primarily as animal feed until the 1920s, at which point they also began to be commercially crushed for their oil.
Soybean production greatly expanded in the United States during and after World War II. It was only then that the bean came to be recognized as the remarkable source of high-quality protein and other healthful nutrients that it remains today.
Soybean and soy food: nutrition
Soybeans and their derivative soy foods have long been associated with health food. Across the board, soy foods are low in saturated fat and contain no cholesterol. Soybeans themselves are a rich source of B vitamins, including thiamin, riboflavin, B6, and folate. They also provide iron, potassium, magnesium, and cholesterol-lowering plant sterols. Most notably, soybeans are one of the few dietary sources of isoflavones, compounds that may help promote bone health. However, the nutritional value of any given soyfood can vary greatly, depending on how it was processed.
High-quality protein distinguishes the soybean and its derivatives from other legumes. For some time it has been known that soy protein, when substituted for animal protein in the diet, lowers total and LDL (“bad”) cholesterol and triglycerides without lowering HDL (“good”) cholesterol. Recently, the FDA authorized a nutrition label claiming that at least 25 grams of soy protein a day, as part of a low-fat diet, can lower blood cholesterol levels in people who have high cholesterol. Soy products containing at least 6.25 grams of soy protein per serving are allowed to bear the FDA-approved health claim label.
Despite this, researchers still disagree about whether it’s the protein or some other substance in soy that provides these heart-healthy benefits. It is possible that it’s the soy isoflavones that are responsible. In addition, scientists are also looking at other cardioprotective components of soy, such as fiber.
If soybeans and soy foods tend to give you bloating and gas, stick with tofu or with fermented soy products, such as tempeh and miso. The processes used to create these soy foods seem to eliminate most of the flatulence-causing compounds. Some people believe that adding kombu (a dried seaweed found in Asian markets and health-food stores) to the cooking water for soybeans will help.
For a full listing of nutrients see the National Nutrient Database:
Types of Soy Foods
Just as the taste of soy foods can vary widely, so can their nutritional content. Check the facts on edamame, soymilk, tofu, tempeh, and other soy foods.
Complex phytochemicals in soyfoods
Soy contains a complex mix of phytochemicals, including isoflavones, some of which may act as estrogens or anti-estrogens. Soy isoflavones may also act as antioxidants and have other beneficial effects:
- A diet rich in soy may help protect against several cancers.
- Soy has also been heavily promoted as a remedy for such menopausal symptoms as hot flashes. However, its effectiveness in this respect is far from certain.
- Soy isoflavones are under investigation for their role in building bone and delaying the onset of osteoporosis.
- The isoflavone content in a soy food varies from high to low, depending on how the food is processed.
There is no doubt that the health benefits of soy will continue to be studied for many years to come. Meanwhile, you are most likely better off eating plant-based foods (such as soy) as opposed to foods that are high in saturated fats. That said, many soy products have many additives, including high amounts of sugar and sodium. Edamame, tofu, soybean sprouts, and tempeh are all safe bets. But be wary of the ingredient list in soy-based replacement meat products. If the ingredient list is extremely long and unintelligible, consider an alternative.
Cooking with Soy Foods: 12 Recipe Ideas
Soy foods such as tofu and tempeh are tasty substitutes for meat if prepared properly.
Published January 26, 2016