Soy, soy, the mythical bean

“I heard that eating soy products is actually worse for the environment than eating meat,” you might be told. Or you maybe you’ve heard, “I saw somewhere that eating too much soy gives you breast cancer!”

The soy bean is an omnipresent ingredient in the American diet, showing up in many more foods than tofu, many more drinks than soy milk, even in many common household products.

Along with this versatility, the soybean has long been the subject of controversy, debate, and a host of less-than-scientific claims.

Let’s talk soy, parse through some of the most pervasive myths and misconceptions, and see what science has to say.

How did soy get so big? A brief history of soybean farming

A versatile crop

Soy is an ancient crop. Farmers in China began cultivating the hardy bean as early as 9,000 years ago, according to some sources. The plant served a variety of culinary needs—for sauces, noodles, tofu, and tempeh—but was also harvested for its medicinal properties too.

American farmers weren’t introduced to the crop until much later, around the mid-19th-century. Thanks to the crop’s ability to thrive in a variety of environments—even during times of drought—its popularity rose quickly. Widespread soy farming began taking root. By the end of the century, the USDA encouraged farmers to grow soybeans, not just for human consumption, but as a source of animal feed too.

Throughout the 20th century, soy’s resilience and versatility grabbed the attention of some of the country’s most well-known visionaries and innovators. Scientist and inventor George Washington Carver and automobile pioneer Henry Ford were united in their interest in this “miracle crop.”

By 1937, the Ford company was turning an annual 300,000 gallons of soy into a protective coating for their vehicles: a “bushel of soybeans” for every car built. In 1941, Ford unveiled a “plastic car” reportedly made out of plant materials such as “soybeans, wheat, hemp, flax and ramie.” The onset of World War II would divert Ford’s attention away from plant-based car designs, but also set the stage for an unprecedented demand for soy products.

Soybean farming booms

The war prompted the US to ramp up soy production and process edible fats and oil domestically. The market for soy exploded even more by the early 1950s, when farmers fully realized its potential as a cheap, protein-packed feed option. Throughout the remainder of the century, production rose to keep up with the fast-growing demand for animal meat products.

This expansion was not confined to the US. Brazil saw the sharpest uptick. The country expanded soybean production tenfold, from 1.5 million tons in the early 1970s to 15 million tons by 1979. That expansion is continuing today. For the last half century, Brazil has cleared more land and grown much more soy, surpassing the US in soybean production in 2013. It’s worth noting, though, that most of the profit from soybean farming in Brazil ends up leaving the country. Today, Brazil and the US produce 90 percent of the world’s supply of soy—which has become the fourth most harvested crop on the globe.

It’s not much of a stretch to say that you can find soy in just about everything. It’s primarily used as livestock feed, and it’s perhaps best-known as a high-protein ingredient found in products like tofu, soy milk, and a host of mass-produced, meat alternatives. That’s just the beginning though. You can find soy in food and drink products like chocolates, mayonnaise, salad dressing, tea, supplements, chips and other snacks. You’ll also find it in household products like soap, makeup, clothing, rubber products, ink, and glues.

The miracle crop has clearly proven its versatility and economic potential. But what effect has soy farming had on the environment?

Is plant-based eating doing more harm than good for the planet?

Environmentalism and plant-based eating typically go hand-in-hand. Along with issues like animal welfare and personal health, the desire to fight climate change is one of the more common reasons why folks decide to cut down on eating meat. That’s what makes claims, like the one made in this recent Fox News opinion headline, so attention-grabbing: “Young people like me are going vegan. That’s bad for the environment.”

The commentator goes on to argue that people going vegan or vegetarian are actually posing more of a threat to the environment than those who simply eat meat.

“They think going vegan will help. What they don’t realize is by giving up meat, they might actually be harming the planet,” the piece reads, referencing environmental harms, like deforestation, caused by soy farming. “Little by little, soybeans are destroying the planet. Did the young vegans consider this when they chose to forego their beef burgers for a soy burger instead?”

What makes refuting popular myths like this a little tricky is that the argument contains some partial truths, coated in some superficial logic. But by omitting crucial details, plant-based opponents posit faulty conclusions on very shaky ground.

Let’s clear things up.

How soy, deforestation, and climate change are all connected

There’s no question that the ever-expanding production of soybeans is directly tied to deforestation. Brazil’s position as a leading soy producer has also contributed to its position as one of the world’s most deforested countries. (The ever-expanding animal agriculture industry is another—and likely more significant—driver of deforestation in Brazil, but we’ll talk more about that soon.) While a soy moratorium has helped slow down deforestation rates in the country’s precious Amazon rainforest, other vital ecosystems like the Cerrado and the Pampas remain under dire threat.

The gravity of deforestation cannot be overstated. In addition to destroying the habitats of countless creatures who live there, bulldozing down rainforests exacerbates the effects of climate change by eliminating carbon sinks, one of the planet’s key defenses against the greenhouse gas effect.

Resources like rainforests and the ocean are known as carbon sinks, because they actually absorb carbon dioxide—a greenhouse gas—out of the atmosphere. Human industrial activity is already emitting far too much carbon into the atmosphere for these natural resources to offset. Deforestation only worsens the problem by clearing millions of acres of trees that could help to absorb the dangerous greenhouse gas from our atmosphere.

So the anti-soy argument looks logical on paper. Soy is connected to deforestation, deforestation is connected to climate change. Therefore, vegans eating soy products are the real problem, right? But are plant-based eaters really the ones eating the most soy?

Soy is only part of the story: animal agriculture drives most soy production

Despite the seemingly countless uses in foods, drinks, and non-edible products that humans have found for soy over the thousands of years we’ve been growing it, it’s primarily grown today for one purpose—to feed cows, pigs, poultry, and other animals who are raised to be slaughtered.

The statistics vary slightly from year to year, and source to source. But we know that somewhere between 70 to 80% of all soybeans grown end up getting fed to farmed animals. The remainder mostly gets used to produce biofuel, vegetable oils, and non-food products. In fact, it’s just a small fraction—around seven percent—of all soy production that’s used in vegan foods like tofu, soy milk, and tempeh.

The anti-soy argument falls flat in the face of such stark statistics. Calling vegans and vegetarians the problem is like a mean older brother who gobbles up your birthday cake and calls you selfish for eating some of the crumbs he left behind.

At this point, the science is clear. Producing meat leaves behind a deep carbon footprint, and a drains a whole lot of resources. Researchers time and time again have come to the conclusion that leaving meat off the plate, and choosing a plant-based diet instead, is one of the most positive impacts an individual can have on the environment and the climate.

Just to drive the point home a little further. I should mention that soy is by no means the sole source of deforestation. While forests in Africa and Asia are mostly lost in being converted to croplands, three-quarters of the deforestation in South America is the result of something else. Maybe you can guess what it is. Livestock grazing: precious stretches of ecosystem cleared to make room for cows who will be raised for food.

If someone’s telling you that the soy from your plant-based diet is what’s destroying the planet, they’re either misinformed or disingenuous.

And while we’re here, let’s dive into some other prevalent myths about soy.

Is eating soy a health risk?

I remember standing in line at a bagel shop once with a friend of mine who happened to be an omnivore. He asked what I was thinking of ordering, and I said I’d probably try the soy-based, faux “tuna salad” option on the menu.

“You know that eating soy messes up men’s testosterone because of its estrogen levels?” he said, as I looked back at him, dubious.

He concluded, “Something to think about.”

Well, perhaps it’s something to “think about,” but that doesn’t mean it’s true.

Anyone who has consumed soy-based food in front of an ardent meat lover probably has a similar story—getting confronted by a friend, relative, or nosy bystander who propagates one of the common myths that soy is either linked to breast cancer or will somehow otherwise wreak havoc on your endocrine system (AKA your hormones).

Where do these pervasive, though inaccurate, claims come from?

Soy’s supposed link to breast cancer and other problems

It’s all rooted in compounds found in soy called isoflavones. These natural plant compounds have a similar makeup to human estrogen, and in early studies, researchers found that pumping lab mice full of isoflavones promoted the growth of breast cancer cells.

Concerns that soy consumption will cause breast cancer in humans have endured ever since. However, the mice in those studies were exposed to far higher levels of isoflavones than anyone eating a soy-based diet would ever be. To further refute those findings, scientist have now learned that humans break down isoflavones differently than rodents.

More up-to-date research actually not only debunks the soy-cancer myths, but has found evidence to the contrary. In 2021, researchers reviewed more than 400 observational and clinical studies regarding soy consumption, and concluded that the evidence bears out that soy should not be classified as an endocrine disruptor—a substance that interferes with our hormones.

The Mayo Clinic reports that a “lifelong diet rich in soy foods reduces the risk of breast cancer in women.” And according to the National Cancer Institute, soy isoflavones have been shown to reduce tumor cell proliferation, regulate hormone balance, and reduce the risks of heart disease and osteoporosis. Nutritionists also advise that diets that include plenty of soy can help lower bad cholesterol and improve vascular function.

As with any type of food, there’s less evidence the ultraprocessed, soy-based products can promise the same health benefits compared to fresher, minimally processed soy foods.

Stay ahead of misinformation

At a fundamental level, the arguments against soy come from the same place as the arguments against eating meat—that the food we eat has real and immediate impacts on the health of the planet, and on our own health. Unfortunately, misinformation muddies the waters, and allows some folks to come to conclusions that are the opposite of the truth.

These days, it’s easier than ever for misinformation to spread far and fast. I know from lifelong experience that some people can’t help but tell plant-based eaters that their dietary choices are wrong. And for those people, it becomes a point of pride to advocate for omnivorous eating.

In the case of soy, these two phenomena combine to create a perfect storm that results in health or planet-conscious eaters having to listen to debunked theories and outright myths aimed at convincing them to eat fewer plants. The best defense is to simply keep a level head, and rely on trustworthy, research-based information from reputable sources.