✓ Evidence Based

Soybean: Facts, Nutrition, Benefits, and More

Soybeans are one of the most common and excellent sources of plant-based proteins, and for good reason. In addition to the protein they contain, soybeans are high in different vitamins, minerals, and fiber.

They are available in a variety of different products and can be eaten in many dishes and snacks.

Besides being a tasty part of a nutritious diet, they offer a ton of health benefits.

Keep reading to find out all you need to know about soybeans.

Fun Fact:The average American consumes seven gallons of soy oil annually.

History & Facts

Soybeans (glycine max), or soya beans, are a type of legume that belongs to the pea family (1). They are traditionally native to eastern Asia. They were first domesticated in China around 7000 B.C. and first introduced to the United States in 1804. Interestingly enough, they grow on bushy plants that are around 2 ½ feet tall.

Today, soybeans are mostly grown in Asia, South America, and North America (2). Throughout the last thousands of years, they remain an important part of Asian cuisine and diets. In Asia, soybeans are often eaten whole, but heavily processed soy products are much more common in Western countries.

Did You Know?:Each soybean plant can grow around 60-80 pods.

Varieties of Soybean

There are over 2,500 different varieties of soybeans that come in many different shapes, sizes, and colors.  The following are the most common seen on the market:

  • Green soybeans: Green soybeans, or edamame beans, harvest about a month before the pods mature and become brown and dry. Most often they are eaten in salads, stir-fries, and soups. Many people steam them and eat them out of the pod as an appetizer, and may have salt and/or other condiments (3). These beans may range in color from light brown to tan, or beige.
  • Yellow soybeans: Yellow soybeans are mainly for food production.  Producers typically use them to make soy milk, tofu, tempeh, and tamari. Furthermore, it can make soy flour for baking from medium or small yellow soybeans.
  • Black soybeans: Several Asian food cultures simmer or ferment black soybeans in traditional dishes. The black soybean is often eaten as a part of the traditional Japanese New Year meal. Pure black soybeans are typically harder to find but can be found more commonly as black soybean tofu and black soybean natto.

Summary:There are over 2,500 different varieties of soybeans that come in different shapes, sizes, and colors, with green, yellow, and black soybeans being the most popular.

Nutrition Facts

Soybeans boast an exceptional nutritional profile.

Macronutrients

In a half-cup (approximately 93 grams) serving of raw soybeans, there are the following macronutrients (4):

  • Calories: 415 calories (kcal)
  • Protein: 34 grams (g)
  • Total Fat: 18.5 grams (g)
  • Carbohydrate: 28.1 grams (g)
  • Fiber: 8.6 grams (g)

As you can see, soybeans are a nutritionally dense food. High in protein, they are also a great source of fiber and healthy fat (5). As far as fiber content they are one of the highest natural food sources of fiber.

The soybean protein content is typically 36-56% of its weight. Additionally, the protein in soy is a complete protein (6). This means that it contains all nine essential amino acids from the diet. For this reason, soybeans are a large protein source for many people, especially those who follow a vegan or vegetarian diet. Although the nutritional quality of soy protein is very good, the quality is not quite as high as animal proteins.

Summary:Soybeans are a nutrient-dense food, being one of the best sources of complete plant-based protein and high in fiber.

Vitamins & Minerals

In a half-cup (approximately 93 grams) serving of raw soybeans, there are the following vitamins and minerals (7):

  • Calcium: 257.5 milligrams (mg)
  • Iron: 14.6 milligrams (mg)
  • Magnesium: 260.5 milligrams (mg)
  • Phosphorus: 655 milligrams (mg)
  • Potassium: 1675 milligrams (mg)
  • Sodium: 1.86 milligrams (mg)
  • Zinc: 4.5 milligrams (mg)
  • Copper: 1.5 milligrams (mg)
  • Selenium: 16.5 micrograms (mcg)
  • Folate: 349 micrograms (mcg)
  • Choline: 108 milligrams (mg)
  • Beta carotene: 12.1 micrograms (mcg)
  • Vitamin A: 20.5 IU
  • Vitamin K: 43.7 micrograms (mcg)

Soybeans are high in several vitamins and minerals and are an exceptionally great source of bone-healthy nutrients (8). Calcium, phosphorus, and magnesium work together to make bones and teeth exceptionally strong. Zinc, iron, and copper, all present in soybeans are necessary for bone and collagen synthesis. Vitamin K is important for bone mineralization and metabolism in bone health (9). For those who cannot have dairy products or prefer to avoid them, soybeans and soybean products like soy milk are a great alternative to dairy and help ensure adequate intake of calcium.

In addition to these nutrients, soybeans are a great source of folate and thiamine, both of which have various functions throughout the body and play important roles.

Summary:Soybeans contain astounding amounts of bone-promoting nutrients like calcium, phosphorus, magnesium, iron, zinc, and copper.

Health Benefits

Other than the abundance of nutrients they contain, soybeans also offer a variety of health benefits.

May Lower Cholesterol

Tons of research over recent years has found a link between soybean and soy-based food consumption and healthy cholesterol levels. These studies conclude that consuming soy, like soybeans, significantly reduces total cholesterol levels, low-density lipoprotein (LDL) cholesterol, and triglycerides (10). LDL cholesterol is also known as the “bad” cholesterol because it can clog arteries.

Furthermore, these studies also note an increase in high-density lipoprotein (“good”) cholesterol which altogether helps lower the risk of heart disease (11). Heart disease is the leading cause of death for men, women, and people of most racial and ethnic groups in the United States (12). An estimated one person dies every 33 seconds in the United States from cardiovascular disease.

It is important to note that these results were more effective with more whole soy-based foods like soy milk, soybeans, and soy nuts.

Summary:Research concludes that consuming soybeans and soy-based food significantly reduces LDL “bad” cholesterol levels and increases HDL “good” cholesterol, which can decrease the risk of heart disease.

May Promote Bone Health

There are tons of nutrients in soybeans that promote healthy bones. For some, women with osteoporosis consume compounds from soy, soy isoflavones, in place of hormone replacement therapy. Osteoporosis is a bone disease that develops when bone mineral density and bone mass decrease, or when the quality or structure of bone changes. Therefore, this can lead to a decrease in bone strength which can increase the risk of broken bones and fractures.

Studies suggest that soy isoflavones are as effective as hormone replacement therapy for restoring bone density (13). This research also found that consumption of soy products may reduce the risk of osteoporosis in women who have undergone menopause.

Summary:Soy compounds like soy isoflavones may be a substitution for hormone replacement therapy, which can restore bone density and reduce the risk of osteoporosis.

May Reduce Cancer Risk

Cancer is one of the leading causes of death today. There is speculation that consuming soy products may increase breast tissue in women which may increase the risk of breast cancer. However, actual studies have found the opposite.

Consuming soy products may potentially decrease the risk of breast cancer and have a protective effect against prostate cancer in men (14). However, it is not clear if more processed soy products like soy protein powder, protein bars, textured vegetable protein, etc., have the same cancer-preventing effects.

Once soybeans are consumed, they are fermented by bacteria in your colon, leading to the formation of short-chain fatty acids (SCFAs). This may improve gut health and reduce the risk of colon cancer (15).

Summary:Consuming soy products may decrease the risk of breast and colon cancer and may have a protective effect against prostate cancer in men.

Ways to Consume

Other than soybeans, there are a ton of soy products available on the market and/or can be made from soy.

Some of these products include:

  • soy flour
  • tofu
  • soy sauce
  • soybean oil
  • soy cheese
  • soy protein powder
  • protein bars
  • textured vegetable protein

Some of the soy products with lesser processing that can be found on the market or made in recipes include:

  • edamame
  • tempeh
  • cooked soybeans
  • soy milk
  • soy nuts
  • Mix in soup recipes
  • Add to stir fry
  • natto
  • miso
  • soy yogurt

Fun Fact:In addition to being used in the food industry, soybeans also find their way into candles, cleaning products, and hair-care products.

Potential Risks

Soybeans are generally considered healthy and part of a balanced diet for most people. However, there are some risks for some to consider.

  • May Cause Digestive Issues: Soybeans are high in both insoluble and soluble fiber. The insoluble fibers consist mainly of alpha-galactosides, which belong to a class of carbohydrates FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) that the small intestine absorbs poorly. For some, the alpha-galactosides may cause flatulence, and diarrhea, or may even exacerbate irritable bowel syndrome (IBS) symptoms (16). Despite the potential for unpleasant side effects, the fiber in soybeans is generally healthy.
  • May Suppress Thyroid Function: There is some concern that soy intake may interfere with thyroid function. In a study of women and men on a vegetarian diet who consume soy foods, women with higher soy intake have a higher chance of having higher levels of thyroid-stimulating hormone (TSH) (17). A high TSH level may signify an underactive thyroid. The researchers conclude that soy is likely to be safe, however, may cause health risks in some people when consumed at high amounts. Another study concludes that regular consumption of soy products or soy isoflavone supplements may lead to hypothyroidism in sensitive individuals, especially those who have an underactive thyroid gland.
  • Soy Allergy: Soy is one of the “Big Nine”, the top 9 food allergens out there. Soy allergy is triggered by the proteins in soy which can be found in most soy products (18). With this, soy allergy may cause hives, swelling, wheezing, abdominal pain, and/or even anaphylaxis. Even though soybeans are one of the most common allergenic foods, soy allergy is relatively uncommon in both children and adults.

Summary:Soybeans are generally safe to consume but may cause allergy, and adverse gastrointestinal effects, and may suppress thyroid function in high amounts of soy consumption.

Frequently Asked Questions

Is soy safe to consume?

Technically yes, soy is safe to consume (19). Many products on the market, soybean being one of the most popular, are made from genetically modified organisms (GMO). According to the World Health Organization (WHO), genetically modified organisms (GMOs) are “organisms (i.e. plants, animals or microorganisms) in which the genetic material (DNA) is altered in a way that does not occur naturally by mating and/or natural recombination.”

There are many concerns about the health impacts of GMOs and their safety. Data from 2020 says that about 55 percent of the total harvested cropland in the United States is grown with varieties having at least one genetically modified trait, the most prevalent being herbicide tolerance and insect resistance (20).

Some studies conclude that eating GMOs may lead to illnesses and questions about their long-term safety (21). Despite these concerns about GMO crops, WHO concludes that they are safe and have passed risk assessment (22). They state “Genetically modified foods currently available on the international market have passed safety assessments and are not likely to present risks for human health. In addition, no effects on human health have shown as a result of the consumption of such foods by the general population in the countries where they are approved.”

More research is taking place on the health impact of these organisms. Some foods have the label “non-GMO” or “100% organic soy” which indicates they do not contain GMO.

Did You Know?:Soybeans were first grown in the United States as cattle feed.

Conclusion

Consuming soybeans and soy-based foods is part of a balanced diet that may offer a variety of health benefits.

Finding foods made of soy is easy as they are part of several foods on the market today. Naturally, they are high in protein, fiber, and nutrients like calcium, iron, and phosphorus all great for bone health.

More research is necessary and in process of studying genetically modified soy to assess its overall benefits and risks, but it is overall deemed as safe.

Try some soybeans today and see for yourself what you are missing!