Is Soy Milk Good for You? 8 Benefits of This Popular Dairy Swap

Despite the plethora of choices out there, one plant-based milk you’re almost guaranteed to see at every supermarket is soy milk. But as far as non-dairy milks go, is soy milk a healthy option? How do its nutritional perks compare to cow’s milk—or is it more akin to water? Are there any risks associated with soy intake? Let’s dive into everything you need to know about soy milk, how good it is for you, and more.

What Is Soy Milk?

Soy milk was one of the first plant-based milk alternatives to hit the mainstream market in 1996. And while it took a few decades for alternative milks to gain popularity, they seem to have hit their stride these days. There’s a seemingly infinite number of non-dairy milk options to choose from: oat, almond, cashew, rice, and soy milk are common choices for consumers, as are more niche varieties like pistachio, walnut, hazelnut, and even sesame seed milk. 

Soy milk is made by simply blending water with soaked soybeans, then straining the mixture to remove any remaining solids. This milk-like beverage can be fortified with nutrients like calcium and vitamin D to make its nutrition profile more similar to cow’s milk; sweetened (typically with cane sugar); or even flavored with chocolate, vanilla, strawberry, and more. 

Some brands will also contain additives like stabilizers and thickeners to make the texture and consistency of soy milk more similar to that of the cow’s milk many of us grew up drinking. Hint: Many of these added ingredients will have the word “gum” in their name on food labels.

Soy Milk Nutrition

People turn to dairy milk alternatives like soy milk for any number of reasons ranging from lactose intolerance, a plant-based lifestyle, or simply a preference to stock up on shelf-stable milks.

Soy milk also gives them a ton of vital vitamins and minerals, even when it's not fortified. Here's a look at what's inside one cup of soy milk.

• Water - 220 grams
• Calories - 105 kcal
• Protein - 6.34 grams (12.68% of the recommended daily value or DV)
• Fat - 3.59 grams
• Carbohydrates - 12 grams
• Fiber - 0.488 grams (1.74% DV)
• Sugars - 8.91 grams
• Calcium - 300 milligrams (23.08% DV)
• Iron - 1.02 milligrams (5.67% DV)
• Magnesium - 36.6 milligrams (8.71% DV)
• Potassium - 298 milligrams (6.34% DV)
• Sodium - 115 milligrams
• Zinc - 0.634 milligrams (5.76% DV)
  

Health Benefits of Soy Milk

Overall, soy milk is good for you, and it’s the most nutritionally similar to cow’s milk (though there are a few key nutritional differences between them, which we’ll get to). Here are some of the health benefits found in soy milk.

Supports Immunity

Soybeans, and thus soy milk, are packed with plant compounds, especially isoflavones and saponins. One isoflavone found in soy milk is genistein. Genistein has been found to ward off cancer cells in the body, through a variety of therapeutic pathways including interference in cancer cell growth and reproduction.

All plant chemicals found in soy, including genistein, are also excellent antioxidants with anti-inflammatory properties. These bolsters the immune response, helping the body ward off both acute and chronic illness. Speaking of antioxidants, soy milk also boasts impressive amounts of vitamin A and zinc, which offer the same benefits.

Boosts Energy

Soy, and therefore soymilk, is one of the few plant-based proteins that contains all nine essential amino acids, making it a complete protein. Not only will this protein help your body maintain and grow healthy tissues, but it will also result in healthy energy levels throughout the day. 

Depending on the fortification of the soy milk in question, you may also find B vitamins like riboflavin, B6, B12, and folate. These, too, support healthy growth, development, metabolism, and energy levels. Interestingly, one randomized control trial found that older men who underwent a resistance training program in combination with drinking soy milk experienced better performance, body composition, and skeletal muscle growth and maintenance.

Promotes Heart Health

This beverage supports a healthy heart from multiple angles. It is low in saturated fat, unlike full-fat dairy, which can encourage healthy cholesterol levels, as can the unsaturated fats, like omega-3 fatty acids, it contains. You’ll also find potassium in soy milk, which helps to regulate heart rhythms and blood pressure, as well as vitamin K, which is integral to healthy blood clotting.

Research supports these benefits, with one review finding the isoflavones in soy milk to reduce the risk of developing heart disease, while another found soy milk to be an overall cardioprotective agent, thanks to its ability to address multiple risk factors mentioned above. Meanwhile, a 2021 meta-analysis found soy intake to be linked with lower blood pressure levels in adults and a prospective cohort study from that same year found consuming soy four or more days per week was linked with a lower incidence of mortality from heart attack.

Protects Gut Health

For those who are sensitive to dairy or lactose, soy milk is the perfect choice as it’s naturally lactose-free. Plus, one 2020 study found soy milk to reduce systemic and gut inflammation while also improving the health of the gut microbiome due to the fiber it contains. And the health of the gut microbiome is tied not only to gastrointestinal health, but whole body health as well.

Eases Menopause and Premenstrual Symptoms (PMS)

Soy milk’s plant compounds, like isoflavones and genistein, are also categorized as phytoestrogens. Phytoestrogens are plant compounds that mimic estrogen found in the body and can help ease some of the most irritating symptoms of menopause. In fact, one meta-analysis examining 15 separate studies found phytoestrogens to help attenuate hot flash symptoms.

Studies suggest that soy has beneficial effects on premenstrual syndrome (PMS) symptoms, as well, due to the influence of soy isoflavones on endogenous oestrogen. Isolated soya protein (ISP) was proven to reduce the severity of PMS symptoms within a seven-menstrual cycle, double-blind, placebo-controlled study of 23 women between the ages of 18 and 35 years. While more conclusive evidence is needed to suggest soy protein (including soy milk that's high in protein) as a remedy for PMS symptoms, this research shows that it can't hurt.

Maintains Bone Health

Fortified soy milks often contain added vitamin D and calcium. These nutrients, in combination with vitamin K, are essential for growing and maintaining healthy bones. The isoflavones found in this alt milk also stand up to bone loss in certain individuals, with a 2022 report published in the Journal of Clinical Medicine finding soy isoflavones to be linked with reduced bone loss in women after menopause.

Reduces Cholesterol

The main components of soy are polyunsaturated fatty acids, lecithin, and stigmasterol, which are all ingredients that have been shown to help reduce total cholesterol. They've also been linked to low-density lipoprotein cholesterol levels, which can help improve diabetes (or prevent it from occurring in the first place). Through the fermentation process, the nutritional value is enhanced, which helps to improve the digestibility of soy protein, too.

Boosts Brain Health

A few other honorable-mention nutrients help make soy milk good for you, including magnesium and iron. Magnesium can support sleep and nervous system health, while iron is vital for healthy red blood cell formation, both of which matter for your brain. Meanwhile, another isoflavone found in this beverage, daidzein, has been linked with neuroprotective benefits, supporting overall brain health.

The isoflavones in soy milk mimic the effects of estrogen in the body and impact the production of neurotransmitters like serotonin and dopamine. This means that they also directly influence mood. Their antioxidant and anti-inflammatory properties also reduce oxidative stress, which is linked to mental health conditions.

Soy Milk vs. Whole Milk

Soy milk and whole milk are both solid options for everything from your coffee to your cereal. However, there's no denying that they have very different tastes and nutritional profiles (even though soy milk does have a lot of the same nutritional benefits as cow's milk).

Because soy milk is made from soybeans and is lactose-free, it's often fortified with a lot of the vitamins and minerals (like calcium and vitamin D) that cow's milk naturally contains. But it still has a lot of the same amino acids and is low in saturated fats, unlike fattier whole milk.

Because cow's milk—and whole milk, in particular—contains more fat, it has a creamier texture that some people prefer, especially in coffee and tea. However, it also tends to be higher in cholesterol, which can be concerning for people who try to watch their cholesterol levels and overall heart health.

While soy milk may be more suitable for lactose-intolerant people and anyone looking for a lower-saturated fat alternative, cow's milk tends to be more nutrient-dense and supportive of healthy bones. Whole milk should be consumed in moderation due to the higher fat levels.

Is Soy Safe for Everyone?

You may have read or heard that soy and soy products have negative consequences on thyroid health, or that it’s even linked to certain types of cancer. Thankfully, there has been plenty of research conducted on soy safety, and the current evidence negates these worrisome claims.

A 2019 systematic review published in Scientific Reports found there to be no link between soy intake and thyroid function, with only a small connection between high soy consumption and slightly elevated thyroid stimulating hormone (TSH). The researchers noted these lab findings to have unclear, but likely negligible, clinical significance.

On the cancer side of things, there are literally dozens of studies negating any connection between soy and isoflavone consumption and the cancers most commonly linked to it: breast and prostate cancers. Two meta-analyses actually found soy isoflavone intake to be tied to a reduced breast cancer risk in women.

Another paper published in Cancer found that soy isoflavone intake in women who were undergoing breast cancer treatment was actually linked to reduced mortality risk. In terms of prostate cancer, one systematic review published in Nutrients found that soy consumption also reduced the risk of prostate cancer. And, finally, another review found that neither soy nor soy isoflavone consumption affected male reproductive hormones, which is another common misconception.

How to Pick a Healthy Soy Milk Product

Before serving soy to your loved ones, there are a few things to keep in mind. The first is to ensure that you’re not serving this milk to anyone who may have a soy allergy, as this legume is a common allergen. Next, consider looking for unsweetened soy milk varieties to avoid consuming too many added sugars. Finally, it’s a great idea to opt for a brand that fortifies its soy milk with some of the micronutrients mentioned above (e.g. vitamins and minerals). This will help you get the most nutritional bang for your buck out of each serving.

Another avenue is to make soy milk at home—either with a blender and cheesecloth or nut milk maker, like Almond Cow. This gives you more control over unwanted additives and mystery ingredients. You’ll have an unfortified, though still nutritious, final product.

While soy milk may be a bit more expensive than cow’s milk, the impressive health benefits associated with it are more than worth it. Enjoying one to two servings of this alternative a few times per week is a great way to take advantage of all that soy milk has to offer.