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Soybean oil is a cooking oil that’s made from the seeds of the soybean plant.

“The seeds get cleaned and dried, then cracked and the hull is removed. Once the bean is cracked open, it’s turned into flakes, and a solvent wash removes the oil from the flakes before it’s bleached and deodorized,” says integrative dietitian Jessica Cording, R.D.

Soybean oil is very prevalent in processed foods because it has a neutral flavor and is cheap to make. In fact, it is the most widely consumed oil in the U.S., as well as the main oilseed produced in this country. According to the USDA, soybeans make up 90% of America’s oilseed production.

In addition to its neutral flavor, soybean oil’s high smoke point (450 degrees Fahrenheit) also makes it a common choice for cooking, especially in fast food restaurants.

• Calories: 120
• Total fat: 13.6 grams
• Polyunsaturated fats: 7.8 grams
• Monounsaturated fats: 3.1 grams
• Saturated fats: 2.1 grams
• Trans fats: 0.1 grams
• Protein: 0 grams
• Carbohydrates: 0 grams
• Vitamin E: 1.1 milligrams
• Vitamin K: 25 micrograms

• Cold-pressed: Cold-pressed oils are made without applying heat. Instead, the seeds are crushed and oil is forced out via pressure. This helps retain some of the nutrients in the oil, since heat can contribute to oxidation and the breakdown of nutrients. Cording says these types of oils may not have the same neutral taste as refined oils, however, and they’re more difficult to find.
• Organic: Organic soybean oil isn’t easy to find either, since soybeans in the U.S. are often genetically modified and treated with the herbicide glyphosate. There are some options available online, but they’re more expensive than other types.
• Vegetable oil / soybean oil blends: There are two types of soybean oil blends you’ll typically find: soybean oil that’s blended with canola or vegetable oil, or olive oil that’s cut with soybean oil. In the latter case, manufacturers usually do this to save on production costs. The oil is often marketed as olive oil, but it has a much cheaper price tag because it has lesser-quality oils mixed in.

1.

It may lower cholesterol.

Unsaturated fats, like those found in soybean oil, are typically credited with lowering LDL (or “bad”) cholesterol and raising HDL (or “good”) cholesterol. And there’s a decent amount of scientific evidence that backs up this benefit for soybean oil specifically. In a 2021 review2, researchers found that replacing dietary saturated fat with soybean oil could lower LDL cholesterol without increasing inflammation or oxidative stress.

Another 2021 study3 found similar results, but this one went further and looked at LDL particle size, which is an important indicator of heart disease risk. The researchers found that when compared to other oils, like hydrogenated soybean oil and a palm oil/palm kernel oil mix, soybean oil didn’t raise the small size LDL particles as much. This is a worthy callout since the small size particles are associated with atherosclerosis4.

2.

It can support heart health.

Lower LDL levels tie in to better heart health, but soybean oil may have some additional benefit here too. For starters, it contains omega-3 fatty acids, which have been linked to better heart health and a reduced risk of cardiac arrhythmias5.

According to a 2021 report6, two separate clinical trials showed increased eicosapentaenoic acid (EPA) levels and a better omega-3 index in adult overweight subjects who consumed soybean oil. This confirmed the ability of stearidonic acid (SDA)—for reference, soybean oil contains about 20% stearidonic acid7—to raise EPA plasma levels.

3.

It may help balance blood sugar since it’s a source of fat.

4.

It contains vitamins and some beneficial fatty acids.

1.

It can be pro-inflammatory.

Inflammation is one of the biggest concerns surrounding soybean oil. And soybean oil can lean pro-inflammatory depending on how much you’re consuming. The polyunsaturated fats in soybean oil are mostly in the form of omega-6 fatty acids. This isn’t a major concern on its own, but it can be problematic when you look at what the typical American is eating.

Before oil refining, humans’ diets were chock full of omega-3 fatty acids from wild-caught fish, wild game, and natural fats. But industrialization brought a shift. As processed foods became more readily available, consumption of omega-6 fatty acids went up drastically, while intake of omega-3 fatty acids started to decrease.8

The ideal ratio of omega-6s to omega-3s is 2:19, but the average American consumes the two fats in a ratio of 10:1 to 20:1. In other words, we’re collectively eating 10 to 20 times10 more omega-6 fatty acids than omega-3s. The consumption of soybean oil specifically also increased 1,000-fold11 from 1909 to 1999—and it’s likely even higher now.

When consumed in such excess, omega-6 fatty acids can contribute to inflammation12—especially if you’re not eating the omega-3s needed to combat these processes.

2.

It contains aflatoxins.

Like with peanuts, there’s also a concern about aflatoxins with soy. Aflatoxins are a type of mycotoxin—or toxic compound produced by certain types of molds. In fact, aflatoxins are one of the most toxic mycotoxins13, and soybean oil can be pretty loaded with them14.

Overexposure to aflatoxins can have a number of negative health effects15, including immunosuppression, impaired growth, and even cancer. In fact, aflatoxins are recognized as a global food safety concern by the World Health Organization.

3.

It is susceptible to oxidation.

When soybean oil is exposed to heat, light, and/or oxygen, it can become oxidized. When this happens, it produces toxic byproducts and potentially harmful compounds that can negatively affect its flavor and your health.

Soybean oil is especially susceptible to oxidation because of its high linoleic content, says Guy Crosby Ph.D., a chemist and adjunct nutrition professor at Harvard University. Linoleic acid oxidizes about 12 times faster than the monounsaturated oleic acid. Soybean oil, specifically, produces about 4.5 times more volatile compounds than olive oil.

4.

Its production can be unsustainable.

Another problem lies in soybean oil’s production. Most soy grown in the U.S. is genetically modified, and sprayed with pesticides and herbicides. One of the most notable of these herbicides is glyphosate16, which has been linked to cancer17, immune issues, and inflammation. Glyphosate also drives antibiotic resistance.

But glyphosate doesn’t just harm your health; it’s also detrimental to the environment. Glyphosate can change the microbial composition18 of the soil, which can affect the guts of animals, plant life; reduce the nutrients in the food you eat; and reduce the carbon-capturing potential of farmland. 

5.

It may negatively impact the brain.

There was also a 2020 preclinical study19 looking at how soybean oil may affect your brain. It’s important to call out that this study involved mice, and not humans, but its findings are interesting nonetheless.

Researchers fed mice three different diets—one with regular soybean oil, one with low-linoleic soybean oil, and one with coconut oil. They found that the groups fed both types of soybean oil experienced genetic changes in the brain, specifically the hypothalamus. These changes could potentially affect energy metabolism, body temperature regulation, neurotransmitter production, and proper brain function. 

“We have to be mindful that it doesn’t directly correlate to what we would see in humans, but it’s a good case for variety in the diet,” says Cording.

Summary

Consuming highly refined soybean oil in large quantities (like what you’ll find in many processed and fried foods) is not healthy. Using cold-pressed or unrefined soybean oil occasionally will not harm your health, but you’ll want to balance it out with other cooking oils like avocado oil and olive oil.

Olive oil has a better nutritional profile overall, with two times as many monounsaturated fats and twice the vitamin E. It also has a lot of antioxidants and other compounds that have proven health benefits, including combating inflammation. 

While the smoke point is lower for olive oil, Cording says this doesn’t really matter as much as most people think it does. As long as you’re cooking at a reasonable temperature—about 350 degrees for olive oil—most home cooks can use either without worrying about burning your oil.

“Coconut oil is in its own category because it’s so different,” says Cording, adding that the main type of fatty acids found in coconut oil are medium-chain triglycerides (MCTs), which your body processes differently. It’s also a lot lower in omega-6s compared to soybean and canola oil, which is a plus.

It’s still recommended to use coconut oil it in combination with other oils, like olive and avocado oil, and it’s best to choose unrefined and/or cold-pressed versions (which go through the least processing) for most purposes.