There are lots of elements of diet and nutrition that are controversial: Are carbs bad for you? Is breakfast the most important meal of the day, or is intermittent fasting and skipping breakfast better for health and weight loss? Is saturated fat bad for you? And the list goes on.
Then, there are polarizing foods as well; one of the most hotly debated is soy.
We often hear asked, is soy bad for you? Is soy good for you? What about soy protein for athletes? Is soy protein bad for you? Is soy vegan?
In this article, we will answer the question, is soy bad for you, discuss the health benefits of soy, the potential drawbacks of soy, and what you should know about soy and your health.
We will cover:
- What Is Soy?
- Why Is Soy Controversial?
- Health Benefits of Soy
- Is Soy Bad for You?
Let’s jump in!
What Is Soy?
Before we try to weigh the pros and cons of soy for your health, it’s helpful to cover a few basics.
What is soy? Is soy vegan?
All soy products come from soybeans. Soybeans are legumes, which is a subtype of vegetable in the same family as beans, peas, lentils, and chickpeas.
Soy is vegan because it contains no animal-derived ingredients.
Soy is rich in protein. In fact, unlike most sources of plant-based protein, soy is a complete source of protein, meaning it contains all nine essential amino acids.
This makes soy an excellent protein source for vegans, vegetarians, and those on plant-based diets.
Much like crops such as corn, soy is eaten whole as soybeans but also processed and used in a lot of other products, seemingly as a filler.
Soybeans are eaten in various forms. Dried soybeans can be cooked and eaten like any other legume and are used in dishes from different cuisines, but since soy is native to Asia, soy is particularly prevalent in traditional Asian recipes.
Edamame is fresh green soybeans and can be eaten raw or steamed. They are also dried and enjoyed as a snack, like peanuts.
Soybean curd is used to make tofu, and soybeans are also fermented into tempeh and miso.
Other parts of the soybean are used and processed in different ways to make everything from sauces and oils to stabilizers and emulsifiers.
Soy protein is also isolated and used in protein supplements for athletic performance and nutrition.
Why Is Soy Controversial?
The primary controversy surrounding soy is whether or not it’s actually good for your health. People are constantly debating questions such as, are soybeans good for you? And is soy protein bad for you?
Soy is rich in nutrients and a complete source of protein.
Diets high in soy have been associated with health benefits, such as improved heart health, lower blood sugar levels, reduced risk of certain cancers, and amelioration of menopause symptoms.
However, soy has sometimes been shown to be an “estrogenic” food, so some people worry that eating too much soy may increase estrogen levels in the body.
The fear with this is that diets high in soy might potentially increase the risk of breast cancer, impede thyroid function, or cause hormonal imbalances, particularly in men.
Let’s get into more detail about the benefits of eating soy so you can answer your question, is soy good for you:
Health Benefits of Soy
Despite some amount of controversy, there’s an undeniably large body of evidence suggesting numerous health benefits of soy.
It is important to note that with all the health benefits of soy, minimally-processed soy foods, such as soybeans, edamame, tempeh, and tofu, appear to provide more health benefits than processed soy products (such as vegan chicken nuggets made with soy protein) and soy protein supplements.
Here are some reasons why soy is good for you:
#1: Soy Is Rich In Nutrients
As mentioned, soy is a complete protein, so it contains all nine essential amino acids.
Soybeans are also rich in heart-healthy polyunsaturated fats, fiber, and several important vitamins, minerals, antioxidants, and polyphenols (beneficial plant compounds).
For example, soybeans naturally contain a lot of iron, magnesium, manganese, copper, and many of the B vitamins.
Many soy products—such as tofu, soy milk, and soy yogurt—are also fortified with additional calcium and vitamin D.
#2: Soy Is Rich In Antioxidants
Perhaps one of the best health benefits of soy is its high antioxidant content.
Soybeans are notably rich in polyphenols, a type of antioxidants that help protect your cells against oxidative damage caused by free radicals and that have been shown to reduce inflammation and provide protection against certain health conditions like heart disease.
Soybeans are especially rich in isoflavones, which are a specific type of polyphenols called phytoestrogens due to their ability to mimic the structure of natural estrogen and activate the body’s estrogen receptors.
It is the potent and high isoflavone content in soy that is thought to be largely responsible for many of the demonstrated health benefits of eating soy-based foods.
With that said, though the chemical structures of estrogen and soy isoflavones are similar, and soy isoflavones do seem capable of attaching to and activating estrogen receptors, research suggests that they have unique effects on the body. This is largely why the concerns of soy-rich diets having “feminizing” effects in men are likely unfounded.
#3: Soy May Support Heart Health
Studies suggest that diets high in legumes, including soybeans and soy-based foods, may help reduce your risk of heart disease by 16% and stroke by 20%.
This benefit is thought to be attributable to soy isoflavones, which seem to help increase the elasticity of blood vessels and reduce inflammation in the endothelial lining of the vasculature.
#4: Soy May Help Reduce Cholesterol Levels
Many studies have found that diets high in soy-based foods may be associated with lowering lower LDL (“bad”) cholesterol levels and raising HDL (“good”) cholesterol levels.
#5: Soy May Reduce Blood Pressure
Soy isoflavones are also thought to help reduce blood pressure, and studies suggest that adding soy foods to the diet can help reduce blood pressure in those with hypertension.
Soybeans are also rich in arginine, an amino acid thought to also help reduce blood pressure.
#6: Soy May Help Reduce the Risk of Certain Cancers
Diets high in soy have been associated with a decreased risk of certain cancers, particularly breast cancer.
Evidence also suggests that soy-rich diets may decrease the risk of colon cancer, lung cancer, prostate cancer, endometrial cancer, and stomach cancer and that soy may improve outcomes and survival for those with cancer.
#7: Soy May Alleviate Menopause Symptoms
Because soy isoflavones mimic estrogen, these phytoestrogens may help somewhat reduce the severity of menopause symptoms by offsetting the rapid decline in natural estrogen.
For example, studies have found that soy isoflavones may help reduce the frequency and severity of hot flashes, vaginal dryness, depression, joint pain, irritability, and fatigue.
Moreover, soy may help reduce the decrease in bone mineral density associated with menopause, which is otherwise linked to an increased risk of osteoporosis.
Additionally, there is some evidence suggesting that diets high in soy isoflavones may reduce bone loss and improve markers of bone health, particularly in menopausal women.
#8: Soy May Reduce Blood Sugar Levels
Studies have demonstrated that soy isoflavones may help lower blood sugar levels and insulin levels.
Evidence also suggests that soy may improve insulin sensitivity and reduce insulin resistance, particularly in people with type 2 diabetes and metabolic syndrome. It seems that soy protein may have these same health benefits as whole soy foods.
Is Soy Bad for You?
The primary reason that people express concern about soy is due to the estrogen-mimicking effects of soy isoflavones. However, evidence suggests that soy isoflavones are weaker and don’t have the same effects as estrogen in the body.
For this reason, there is no evidence to suggest that soy has deleterious effects on male reproductive hormones, such as testosterone, or has feminizing effects in men.
There have also been concerns about the potential ramifications of soy on thyroid function, but human studies have found that there does not seem to be any appreciable adverse effect of high-soy consumption on thyroid hormones or thyroid health.
Overall, soy can be a nutritious food with many health-promoting effects on the body.
There’s little evidence to suggest that diets high in soy are unhealthy, even for men. However, it’s important to note that you should eat minimally-processed soy and enjoy other vegetables and forms of protein as well.
It is also important to stay away from genetically-modified soy products because further research is needed about the potential health consequences of GMOs and genetically-modified soy.
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