Is Cooking With Soybean Oil Bad for Your Health?

Many people simply say "soy." But what's often forgotten is that soy is actually a bean. And that's inherently a good thing when it comes to health. So what's the deal with the oil that's extracted from soybeans?

Soybean oil contains omega-6 fats, which can be inflammatory if you eat too much.
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For starters, soybean oil is an excellent source of unsaturated fats, especially polyunsaturated fat. While unsaturated fats boast some solid benefits, soybean oil is still 100 percent fat — and going overboard with it may be detrimental for your overall health.

Ideally, your best bet is to use unsaturated fats (like those in liquid soybean oil) in place of saturated fats (like those in shortening, which is often used for making flaky pie crust!). But before sautéing soybean oil with your favorite veggies, find out if it's a healthy addition to your diet.

Read more: Is Coconut Oil the Miracle Food It's Cracked Up to Be?

Soybean Oil Nutrition

A one-tablespoon serving of liquid soybean oil provides 120 calories and 13.6 grams of total fat. It's rich in unsaturated fat (7.9 grams of polyunsaturated fat and 3 grams of monounsaturated fat) while containing only 2.1 grams of saturated fat.

On the other hand, a one-tablespoon serving of vegetable shortening provides 113 calories and 12.8 grams of total fat, yet it's significantly higher in unhealthy fats, including 3.2 grams of saturated fat and 1.6 grams of trans fat. Due to their negative impact on health, including the potential to raise bad cholesterol levels, the American Heart Association (AHA) recommends limiting saturated fat and avoiding trans fat in your diet.

Benefits of Polyunsaturated Fats

With their 7.9 grams of polyunsaturated fat in a one-tablespoon serving, soybean oil is considered high in polyunsaturated fat, comprising 58 percent of the total fat content. According to a July 2017 report published in Circulation, polyunsaturated fats are considered good for cardiovascular health, especially when consumed in place of saturated and trans fats.

In fact, heart disease risk was slashed by about 30 percent in diets that limited saturated fats and used polyunsaturated vegetable oil in place of saturated fat. That's a similar decrease in heart disease risk as statins provide!

What's more, polyunsaturated fat includes omega-3 fatty acids, which the body doesn't produce on its own. Omega-3s are a vital feature of the membrane around every cell in the human body, according to the National Institutes of Health. And yes, soybean oil contains omega-3s — specifically, alpha-linolenic acid (ALA). However, soybean oil supplies 0.9 grams of ALA per tablespoon, which is far less than the 7.3 grams of ALA found in a tablespoon of flaxseed oil. So while soybean oil does contain omega-3s, it's not the best source of these healthy fats.

Read more: With the Good Comes the Bad: The Side Effects of Taking Too Much Omega-3

While omega-3s have been studied for their potential ability to reduce inflammation, arthritis and heart disease risk as well as promote brain health and cognitive function, most research is based on the other forms of omega-3s — namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — which you'll find in cold-water fish and fish oil. However, the good news is that polyunsaturated fats can play a role in lowering bad cholesterol levels, which therefore may reduce your risk of stroke and heart disease.

How Much Fat to Use

While oils, including soybean oil, offer healthful fats, they should be consumed in moderation since they're a concentrated source of calories. The U.S. Dietary Guidelines advise a daily intake of 20 to 35 percent of calories from total fat and less than 10 percent of total calories from saturated fat for men and women ages 19 and older. The AHA recommends keeping saturated fat intake to no more than 5 to 6 percent of total daily calories if you need to lower your blood cholesterol.

"The typical diet should have about 25 to 30 percent of calories from (total) fat, with the primary sources being polyunsaturated and monounsaturated fats," says New York City-based registered dietitian, Natalie Rizzo, MS, RD. "Any more than that could contribute to weight gain, since fat has more calories per gram than other nutrients (nine versus four for carbs and protein)," she adds.

However, for those following the Mediterranean diet, a total fat range is not clearly defined as it emphasizes healthy fat intake. And in a January 2014 study in Diabetes Care, which findings suggest a reduced risk of diabetes and stroke, the percentage of fat intake ranged from 39 to 42 percent of total calories.

What does this all mean in your kitchen? Consider using the Dietary Guidelines' recommendation of about 5 teaspoons of oil (27 grams) per day on a 2,000-calorie eating plan as a ballpark. Or simply be mindful — drizzle it modestly rather than dousing your dishes with it.

Read more: Your Ultimate Guide to Fats and Why Your Diet Needs Them

Should I Use Soybean Oil?

With all of the healthful oils available on the market, should you reach for soybean oil first?

"Because soybean oil is high in polyunsaturated omega-3 fats, it's been linked to heart health benefits," Rizzo says. In fact, a September 2003 report in The American Journal of Clinical Nutrition found that woman who ate a salad with soybean-oil-based dressing multiple times per week had a lower risk of developing coronary artery disease.

Separately, a small October 2017 study published in the American Journal of Clinical Nutrition found that eating a salad with the addition of soybean oil promotes the absorption of health-promoting carotenoids and fat-soluble vitamins. What's more, soybean oil offers 1.1 grams of the antioxidant vitamin E — of which most Americans need more. The oil has possible benefits outside of the body, too! "It might be good for sun worshippers, with studies suggesting that applying soybean oil to the skin may reduce sun-induced inflammation," says Rizzo, citing a December 2005 study in the journal Archiv der Pharmazie.

But not so fast! Getting too much polyunsaturated fat, such as that found in soybean oil, has a downside.

"It should be noted that soybean oil is higher in omega-6 than many other plant oils, and too much omega-6 may cause inflammation," says Rizzo. Though some research points to a negative impact on inflammation, Rizzo says that it's OK to use soybean oil in moderation.

And there's one other important consideration with soybean oil: Genetic modification (GM). Since the vast majority of soybeans in America are GM soybeans, according to the USDA, that means most soybean oils fall into the controversial GMO category. A couple of the potential health risks associated with GMOs are antibiotic resistance and allergic reactions, according to a December 2013 in the Journal of Food Science and Technology. One way to avoid these risks is to choose USDA-certified organic soybean oil, which will ensure your soybeans are GMO-free.

Read more: Is Eating Soy Actually Bad for Your Health?

How to Use Soybean Oil

Soybean oil's versatility makes it a great addition to your kitchen. "It's a neutral-tasting oil that can be used in basic cooking," says Rizzo. It works well for sautéing veggies or fish, or as a marinade for these foods prior to high-heat cooking. Because it has a neutral flavor, soybean oil isn't ideal for salad dressings, unless you're going for a mild flavor.

You can use the oil in well-seasoned foods — such as worldly cuisines — as it won't compete with the flavors. "I usually recommend a combination of olive oil and vegetable oil, which usually has soybean oil in it," says Rizzo. She likes vegetable oil because it's affordable, neutral tasting and has a relatively high smoke point. "But if you prefer soybean oil instead of a blend, there's no reason to avoid it."

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