What Are the Benefits of Soybeans? (2024)

Soybeans and products made from soy have been shown to support overall health. Soybean benefits are many: It is a nutrient-rich food, supports post-menopausal health, and potentially lowers cancer risk. Soybeans are a good source of protein, heart-healthy fat, fiber, potassium, and phytonutrients, as well as low in fat. In addition to whole foods, soy is available in supplement form including tablets and powders.

Soy is a product that comes from soybean, a legume that is prevalent in East Asia. It is found in many foods including milk, tofu, edamame, and processed foods like breads, cereals, snack bars, and processed meats. Soy is most commonly eaten as a plant protein as it has all the amino acids that act as the building blocks of protein.

This article discusses the health benefits of soybeans and soy products. It also covers preparation and potential side effects.

Nutrition Facts About Soybeans

A 1/2-cup serving of soybeans contains the following nutrients:

• Calories: 148
• Protein: 15.5 grams (g)
• Total Fat: 7.5 g
• Cholesterol: 0 mg
• Carbohydrate: 7 g
• Fiber: 5 g
• Calcium: 88 milligrams (mg)
• Iron: 4.4 mg
• Magnesium: 74 mg
• Phosphorus: 210 mg
• Potassium: 443 mg
• Zinc: 1 mg
• Sodium: 1 mg
• Selenium: 6.3 micrograms (mcg)
• Folate: 46 mcg
• Choline: 41 mg
• Manganese: 0.7 mg
• Vitamin K: 16 mcg
• Vitamin A: 4.7 mcg
• Beta-carotene: 4.3 mcg
  

Soy Health Benefits

There are many nutritional benefits to choosing soybeans and foods made from soybeans.

High Protein

Soybeans and soy-derived foods are good sources of plant-based protein. It can be more difficult to get enough protein if you follow a vegan or vegetarian diet, soy foods are an important source. Soybeans are 35% to 40% protein by weight and, unlike most plant proteins, soy contains all nine essential amino acids—the building blocks of protein that are needed for muscle and bone growth and repair.

With 15.5 grams of protein, a 1/2 cup serving of soybeans has about the same amount of protein as 2 ounces of fish, chicken, or beef.

Low Fat

A 1/2 cup serving of soybeans contains 7.5 grams of total fat and is made up of mostly heart-healthy fats, including monounsaturated and polyunsaturated fats. These fats may help improve your blood cholesterol when used in place of saturated and trans fats.

No Cholesterol

Another reason soybeans are considered heart-healthy is that they're cholesterol-free. The Dietary Guidelines for Americans recommends keeping dietary cholesterol consumption "as low as possible." Substituting soybeans for foods higher in cholesterol, like beef, pork, cheese, and processed meats may help improve heart health by lowering cholesterol and saturated fat intake.

A meta-analysis of 46 studies demonstrated that soy protein lowered LDL cholesterol by 3% to 4% in adults. Researchers noted this research supports encouraging the general public to increase plant protein intake.

Even though soy protein may have only a small direct effect on cholesterol, soy may still benefit the heart in other ways. A 2020 study of 136,459 women and men who did not have cardiovascular disease at the start of the study found that those who ate the highest amounts of tofu and isoflavones from soy foods, compared with those who ate the least, had an 18% and 13% lower risk, respectively, of developing heart disease.

Supports Post-Menopausal Health

Soybeans contain hormone-like substances called phytoestrogens, which occur naturally in plants. One type of phytoestrogen, called isoflavones is naturally present in soybeans and has a similar chemical structure to estrogen.

Researchers have been focusing on how isoflavones in soy can be used to manage menopausal symptoms.

Hot Flashes

Numerous studies have examined the effect of isoflavone supplements on hot flashes:

• Ten studies showed a significant reduction in hot flashes for those taking soy supplements compared to placebo.
• Seven randomized controlled trials showed no difference between supplement and placebo groups.
• A systematic review of 15 studies using a larger group of post-menopausal study participants reported a reduction in hot flashes and improved quality of life

Bone Health

During menopause estrogen levels decline, which leads to significant bone loss. Soybeans and soy products could positively contribute to bone health because they contain protein, calcium, and isoflavones.

Two randomized controlled trials have shown treatment with soy proteins rich in isoflavones showed a reduction in bone loss.

Another study showed that intake of soy protein increases bone calcium retention in females during the post-menopausal period. Calcium retention reflected a positive bone balance helping to maintain bone volume and increasing bone strength.

Maintaining bone mass and strength is important for preventing osteoporosis and its potential complications.

High Fiber

Soybeans contain 5 grams of fiber per 1/2 cup, which includes both insoluble and soluble fiber. Insoluble fiber can help prevent constipation and soluble fiber can help lower blood sugar and cholesterol levels.

Soluble fiber is also important for gut health. It helps regulate the gut microbiome and is metabolized into short-chain fatty acids, which reduces the risk of gastrointestinal diseases, such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), diverticular disease, and more.

High Potassium

Soybeans are a rich source of potassium, providing 443 mg per 1/2 cup. Most Americans don't get enough potassium, which your body needs for many functions, such as:

• Regulating heartbeat
• Regulating blood pressure
• Proper nerve and muscle function
• Making proteins
• Metabolizing carbohydrates
  

Good Source of Iron

A 1/2 cup serving of soybeans has 4.4 mg of iron, which is especially important for people following a vegan or vegetarian diet. Plant-based sources of iron are not as well absorbed as animal sources, so more is needed to absorb adequate amounts.

Iron is an important mineral that helps maintain healthy blood. Iron is a major component of hemoglobin—a protein in red blood cells that carries oxygen from your lungs to all body parts. Inadequate iron, called iron deficiency anemia, affects 4 to 5 million Americans and causes extreme fatigue and lightheadedness.

Eating soybeans regularly can help to meet your daily iron requirements.

Supports Low Blood Pressure

Studies have examined the effects of soy isoflavone supplements on blood pressure. Some older randomized controlled trials (RCTs) have shown soy isoflavone supplementation reduces blood pressure, while others have not produced the same results.

A 2024 meta-analysis of 24 studies including 1945 participants found supplementation with soy isoflavones effectively reduces blood pressure. The study authors noted that additional high-quality studies are needed to determine the optimal amount of soy isoflavones required to lower blood pressure.

Lowers the Risk of Cancer

Because soy contains plant estrogens (isoflavones) and high levels of estrogen have been linked to an increased risk of breast cancer, some thought soy may increase breast cancer risk. However, food sources of soy don't contain high enough levels of isoflavones to increase breast cancer risk.

In fact, there is growing evidence that eating traditional soy foods (tofu, tempeh, edamame, miso, and soymilk) may lower the risk of breast cancer, especially among Asian women.

These studies have examined the effects of soy on breast and prostate cancer:

• A meta-analysis of 14 studies indicated tofu intake is inversely associated with breast cancer risk—meaning the more tofu consumed, the lower the risk.
• A meta-analysis of 16 studies involving 648,913 participants found moderate consumption of soy-based foods did not affect breast cancer risk, but a high intake of soy-based foods was associated with a lower risk of developing breast cancer.
• A meta-analysis showed cases of prostate cancer were significantly lower in the populations who had higher consumption soy, especially non-fermented soy protein products.

Possible Side Effects of Soy

The most common side effects of soy are stomach upset, constipation, and diarrhea. Soy may change thyroid function in people who are deficient in the mineral iodine.

Some people are allergic to soy and should avoid foods containing soy. Although most children outgrow a soy allergy, some people remain allergic to soy throughout their lives. Symptoms of soy allergy may include:

• Vomiting
• Stomach cramps
• Indigestion
• Diarrhea
• Wheezing
• Shortness of breath, difficulty breathing
• Repetitive cough
• Tightness in throat, hoarse voice
• Weak pulse
• Pale or blue coloring of the skin
• Hives
• Swelling, can affect the tongue and/or lips
• Dizziness
• Confusion

Rarely, a soy allergy can causeanaphylaxis, a potentially life-threatening reaction that impairs breathing, causes a sudden drop in blood pressure, and can lead to cardiac arrest if untreated.

Despite estrogen-like actions from isoflavones found in soy, it is not currently believed that soy products increase the risk of gynecological cancers in women.

Concerns that soy can cause infertility or other problems in men are not based on scientific evidence. A 2021 meta-analysis of 38 studies concluded neither soy nor isoflavone intake affects male reproductive hormone levels.

Preparation

When choosing healthy soy foods, it’s important to read the labels before you make a purchase. Processed foods with soy protein isolate are stripped of most of their nutrients and often combined with unhealthy additives.

When it comes to whole soy products, the following food sources are high in a variety of nutrients such as protein, fiber, potassium, iron, and fiber:

• Edamame: Prepare by boiling in water for 15 to 20 minutes.
• Soymilk: Add to smoothies or use as a replacement to milk for those who are lactose intolerant or sensitive.
• Tempeh: Marinate and grill or cut into slices and sauté for three minutes on each side.
• Tofu: After pressing for 20 to 30 minutes to drain the water, cut into cubes and brown in a skillet for one to two minutes on each side. Toss with your favorite dressing, sauce, or marinade.
• Whole soybeans: Rinse and drain beans before placing them on a baking sheet in the oven at 350 degrees Fahrenheit. Roast for 30 to 45 minutes or until golden and crispy.

Textured soy or vegetable protein, which is most often used as a meat replacement, is a type of soy product made from approximately 50% to 70% soy protein, soy flour, or other soy concentrate, but also likely contains wheat, oat, or other ingredients and therefore is not considered a whole source of soy.

Other forms of soy, such as soy powder which can be added to smoothies, are convenient for their longer shelf life and being a portable source of protein. Just be aware that many of these contain soy isolate and other additives, so it’s best to use them in moderation.

Soy Supplement

If you’re looking for a soy supplement to combat menopause symptoms, talk to your healthcare provider about the best choice for you. A supplement with soy isoflavones will mimic estrogen-like actions and may be able to help symptoms.

Summary

Soybeans and soy-derived foods are good sources of plant-based protein, heart-healthy fat, fiber, potassium, iron, and more. Other potential soybean benefits include easing menopause symptoms, lowering blood pressure, and reducing the risk of some types of cancer. To get these benefits, choose whole soy foods instead of processed soy products. Talk to your healthcare provider if you are considering taking a supplement containing soy isoflavones.