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  • Morgan Sokes

Soy: Lost in translation

If you suffer from soy-phobia, you’re not alone. The soybean may appear to be an ordinary legume, but don’t let that fool you. Soy has been the source of great debate and polarization in the food world. Is it a health-promoting superfood or a toxic substance? Soy is a thing of legend, even known to bestow the power to grow breasts, a power granted to men and women alike. Sorry to the ladies (and gents) who were hoping to move up a bra size, but this is, in fact, a tall tale. All kidding aside, let’s try to mitigate some of the confusion surrounding this mysterious bean by reviewing the myths, drawbacks, and benefits of soy food consumption.

Where does the fear of soy originate?

There is concern that soy might increase a woman’s chances of getting breast cancer. Breast cancer survivors often think they should avoid soy foods that might lead to relapse or accelerator tumor growth. Men sometimes worry about soy products increasing levels of feminizing hormones in their bodies. Part of this is due to press articles and social media posts that may have misinterpreted or miscommunicated facts and research studies.

It is true, soy contains high levels of compounds called isoflavones, a type of phytoestrogen. Hearing this word leads to the assumption that eating soy is basically the same thing as estrogen replacement therapy. Estrogen is the dominant female sex hormone. Men naturally produce estrogen as well, but at much lower levels. Normal female estrogen levels are associated with physical development during puberty, ovulation, and fertility. Excess estrogen is associated with a lot of nasty stuff, including heart attack, stroke, fertility problems, unintended weight gain, cancer, and other conditions. Safe to say, men probably don’t want much of this hormone, and women don’t want too much.

Plant parts are different.

Phytoestrogens come from plants, and though structurally similar, they are not quite the same as mammalian estrogen. Mammalian estrogen can be found in meat and dairy, but not plant-based foods. Plants often possess compounds that have a lot in common with their animal constituents. You may have heard of something called plant sterols, or phytosterols. Though quite similar to human sterols, aka cholesterol, phytosterols actually aid in decreasing blood cholesterol levels when eaten. The point in question is whether phytoestrogens work in the same fashion to lower estrogen levels, or if they mimic human estrogen, consequently raising estrogen levels when eaten. Turns out, the phytoestrogens in soy can act as a weak form of both an anti-estrogenic and pro-estrogenic modulator based on if a person’s levels are lower or higher than normal.

What about GMOs?

The soy controversy only increases when brought into another great food debate, the concerns surrounding GMOs. The majority of soybeans grown in the U.S. are genetically modified, and therefore many people correlated soy with GMOs. The GMO dispute is a topic for another time, but just to clarify, most GMO soy grown in the U.S. is used as livestock feed, not for human consumption. If you’re trying to avoid GMO soy, you might want to start with the products that come from animals who were eating it for the duration of their life. Most soy used for human consumption is not genetically modified, and those labeled organic or non-GMO are never genetically engineered.

What’s to love?

-Soybeans have many positive attributes:

  • High-quality protein- Soybeans contain all essential amino acids. The quality of protein found in different foods can be determined and quantified with a PDCAAS score, which stands for protein digestibility corrected for amino acid score. Eggs set the bar with a score of 1.0. Wheat is down around 0.25, and beef is 0.92. Soy falls in right at or above beef with a range between 0.92 and 0.98.

  • No cholesterol and low in saturated fat- 4 ounces of cooked tofu contains only 1.4 grams of saturated fat while supplying `15 grams of protein.

  • Fiber- The main type of fiber found in soy is well fermented by the gut microbiome, keeping the good bacteria well fed. 4 ounces of cooked edamame (immature soybeans) provides 5 grams of fiber. They are a great salad topper, but also delicious by themselves.

  • Vitamins- Most soy foods are a good source of B-Vitamins and Vitamin K1. Edamame is also a great source of folate and Vitamin C.

  • Minerals- Soy foods are also a good source of magnesium, potassium, calcium, zinc, and iron

  • Plant sterols- Soy foods are a top contributor to these cholesterol-fighting compounds

  • Isoflavones- Yes, those phytoestrogens we’ve been talking about appear to be good for the health of both men and women! They seem to be beneficially selective of the tissues they act on, and also show antioxidant activity.

  • May aid in weight loss- Research in animal and human models has shown that consumption of soy protein can help in insulin-resistance and obesity.

  • Research has indicated that soy may be protective against several health conditions including:

-Prostate, breast, and ovarian cancers


-Heart disease and hyperlipidemia (high cholesterol)

-PCOS, dysmenorrhea, and menopausal symptoms

People who eat soy:

Eastern Asian populations that consume the highest amount of soy have lower rates of prostate cancer, breast cancer, cardiovascular disease, bone fractures, and age-related brain diseases. Women also report fewer menopausal symptoms. Japan’s citizens enjoy the longest life expectancy in the world. The Japanese also enjoy an average of 9 times more soy protein per day than those living in North America and Europe. You might think this must be genetic, but when Asians move to Western nations, disease rates increase as their dietary habits change. Maybe it’s some other lifestyle factor that changes, but it could be at least partly due to the soy.

What’s the catch?

From the above information, it sounds like soy may actually be a magical bean whose powers should be revered, not demonized. Yet not all soy is created equal.

Processed Soy:

The studies on soy and East Asian populations involve the consumption of mostly whole or minimally processed soy foods such as edamame, tempeh, and tofu. Soy nuts and sprouts are also whole soy foods. The soy products we find in many foods of the Western world are usually ingredients such as soy protein isolate, hydrogenated soybean oil, hydrolyzed soy protein, defatted soy flour, and soy lecithin. The bioactivity of these fractionated and isolated components is a lot different. They don’t show the same health benefits. Some processed soy products also contain high amounts of salt such as soy sauce and miso, so if you’re watching your sodium intake these should be kept to a minimum.


Soy allergies make the list of the top eight most common food allergies in the world. If you have a soy allergy, you will not reap the benefits of soy foods

Basically, soy in whole or minimally processed forms is a healthful addition to the diet. Incorporating some of these foods provide quality protein, important nutrients, and some disease protection. I hope this has helped to combat any soy-phobia you may be struggling with. Soy, it turns out, may be nothing more than a misunderstood bean with whom you might want to become friends (with benefits)!

-Barrett JR. The science of soy: what do we really know?. Environ Health Perspect. 2006;114(6):A352-A358. doi:10.1289/ehp.114-a352

-Malekinejad H, Rezabakhsh A. Hormones in Dairy Foods and Their Impact on Public Health - A Narrative Review Article. Iran J Public Health. 2015;44(6):742-758.

-Messina Mark, Messina Virginia. Soyfoods, soybean isoflavones, and bone health: A brief overview. J Ren Nutr. 2000;10(2):63-68. Doi:10.1016/S1051-2276(00)90001-3.

-Rizzo G, Baroni L. Soy, Soy Foods and Their Role in Vegetarian Diets. Nutrients. 2018;10(1):43. Published 2018 Jan 5. doi:10.3390/nu10010043

-Velasquez MT, Bhathena SJ. Role of dietary soy protein in obesity. Int J Med Sci. 2007;4(2):72-82. Published 2007 Feb 26. doi:10.7150/ijms.4.72

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