Soy is a popular legume of Asian origin. Soy is high in plant protein and people can consume it in a variety of ways. People who follow a vegetarian or vegan diet often use soy to replace meat.

Soybeans are healthful and rich in protein, giving them numerous nutritional uses. People can eat them, drink them in milk alternatives, and take them in the form of supplements.

However, there is some controversy surrounding the benefits and risks of consuming soy, as some producers now genetically modify the plant.

Outside of nutrition, soybeans also have other benefits. Manufacturers may also extract the oil from soy and use it to make ecologically friendly fuel, as well as candles, crayons, and engine lubricants.

In this article, learn more about soy, its potential health benefits and risks, and the best forms of soy to consume.

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Soybeans are a high protein plant food that belong to the legume family. People can prepare and eat soy in a variety of ways, and it can provide a substitute for many meat or dairy products.

Soybeans come in many colors, including:

  • Green soybeans: Young green soybeans are also called edamame. People can steam them and eat them out of the pod as an appetizer. Shelled edamame is also available in salads, stir-fries, and soups.
  • Yellow soybeans: Producers typically use yellow soybeans to make soy milk, tofu, tempeh, and tamari. They also play a role in the production of soy flour for baking.
  • Black soybeans: Several Asian food cultures use simmered or fermented black soybeans in traditional dishes.

Soybeans also provide soy oil, which people can use for cooking, biodiesel, and other industrial supplies. After removing the oil from soybeans, people can use the remaining material to make soyfoods like tofu and soy milk, as well as food for farm animals and pets.

Some manufacturers make protein powder and isoflavone supplements from soy. Isoflavones are plant compounds that have a similar structure to estrogen.

Less processed organic soy is the most healthful option. Some examples include:

  • cooked soybeans
  • edamame
  • soy milk
  • tofu
  • tempeh
  • soy nuts

Soy is a complete protein. This means that it contains all nine essential amino acids. It is an important source of protein for many people, especially those who follow a vegan or vegetarian diet.

The nutritional content of soy products may vary based on how manufacturers have processed them and which ingredients they have added. According to the United States Department of Agriculture (USDA), 100 grams (g) of raw mature soybeans contains:

  • 446 kilocalories
  • 36.5 g of protein
  • 19.9 g of fat
  • 30.2 g of carbohydrate
  • 9.3 g of fiber

Soybeans are generally low in saturated fat and high in protein, iron, and folate. They are also a good source of:

Some research suggests that including soy in the diet could have several potential health benefits.

Lowering cholesterol

Some evidence suggests that consuming soy may help to lower cholesterol. For example, a 2021 study suggests that fermented soy products might help to reduce total and low-densitiy lipoprotein (LDL) cholesterol levels. Some people may refer to LDL as “bad cholesterol”.

Similarly, a 2022 study notes that a protein in soybeans can help lower triglyceride and LDL cholesterol levels by blocking an enzyme that plays a role in their production. This may help to reduce the risk of metabolic diseases.

Heart health

Some evidence also suggests that the components of soy may help to reduce the risk of cardiovascular disease (CVD). For example, a 2020 study indicates that the isoflavones present in soy may help to lower the risk of developing coronary heart disease.

Reducing breast cancer risk

According to a 2022 meta-analysis, both pre- and post-menopausal females who consume higher amounts of soy isoflavones may have a lower risk of breast cancer.

A 2019 review also found that Asian females who consumed soy isoflavones had a reduced risk of cancer both before and after menopause. Soy isoflavones may help reduce the growth and spread of hormone associated cancers.

Reducing the risk of type 2 diabetes (T2DM)

According to the same 2019 review of studies, soy isoflavones may also reduce the risk of diabetes. A 2023 systematic review also suggests that soy may help to reduce the risk of CVD and T2DM. A 2020 article suggests that soy may help to lower the risk of developing T2DM due to its impact on glycemic management.

Reducing osteoporosis risk

Soy isoflavones may also help improve bone density in postmenopausal females who are at risk of developing osteoporosis. This is a condition affects bone growth and leads to easy fractures. Some studies have suggested that soy isoflavones may be as effective as hormone replacement therapy (HRT) for restoring bone density.”

Although health experts generally consider soy to be safe to consume, some people may have some concerns.

Soy allergy

Soy is one of the most common food allergens. When a person with a soy allergy has exposure to soy, it triggers their immune system, leading to reaction symptoms that can be mild or very severe. As such, it is advisable for people with a soy allergy to avoid products containing soy.

Thyroid function

Previously, there was some concern that soy intake may interfere with thyroid function. However, a 2019 systematic review suggests that soy is unlikely to have much effect on thyroid hormones.

Although, it is worth noting that soy may interfere with levothyroxine absorption. This is a medication that people may take to treat hypothyroidism.

Genetically modified organisms

Genetically modified organisms (GMOs) refer to an organism where genetic engineering techniques have altered the genetic material, or DNA, to create a new variety. There are many concerns around the health impacts and environmental safety of genetically modified crops.

Most soy grown in the United States is GMO soy. Mostly, this is for animal food, soybean oil, and ingredients in processed foods. A 2021 article suggests that GMO soy products are safe to consume and unlikely to damage the environment. The U.S. Food and Drug Administration (FDA) also suggests that GMO soybeans produce healthier oils and are just as safe as non-GMO foods.

If a person wishes to avoid GMOs, they can look for 100% organic soy products or those labeled as non-GMO.

Some FAQs about soy may include:

What does soy do to your body?

Soy is rich in nutrients and beneficial plant compounds that may provide some health benefits. This can include improving heart health, improving bone health, and lowering the risk of certain cancers.

Some people claims that soy may also pose some health risks, particularly heavily processed soy with a high GMO content. Some possible concerns may include potential estrogen-like effects and long-term influence on growth, digestion, sexual maturation, and thyroid health.

However, there is currently limited research supporting these claims. As such, more research is still necessary.

Why avoid soy in diet?

Some people may wish to avoid soy if they have soy allergies. Soy is among one of the most common food allergens.

Is soy a nut or bean?

Soy is a bean and not a nut. Specifically, soybeans are a legume, which includes both beans and pulses. Other foods in the legume family include kidney beans, black beans, chickpeas, lentils, and peanuts.

Does soy affect estrogen?

Soy contains isoflavones, which are a type of plant estrogen. Soy isoflavones can bind to estrogen receptors in the human body and may cause either weak estrogenic or anti-estrogenic activity. However, there is no strong evidence to suggest a link between soy consumption and hormonal changes in the body.

Soy is a rich source of a complete plant protein. There are many different types of soy products that people can consume in different ways. People can include soy foods as part of a varied and healthful diet that may offer health benefits. This may include lowering the risk of metabolic conditions.

It may be advisable for some people to avoid soy products. This can include those with an allergy or those with hypothyroidism. More research is still necessary to assess their overall potential benefits and risks of soy.