Soybean Oil Drug Interactions, Uses, Effectiveness, Safety & More

Soybean oil is a vegetable oil pressed from the seeds of the soybean plant (Glycine max), a legume grown widely in the United States, Brazil, Argentina, and China. It is one of the most commonly used cooking oils in the world and is found in many processed and packaged foods.

The oil is mostly made up of unsaturated fats, including omega-6 (linoleic acid) and a smaller amount of omega-3 (alpha-linolenic acid) fatty acids. It also contains vitamin E and plant compounds called phytosterols.

Besides being used in the kitchen, soybean oil appears in skin and beauty products, in softgel supplement capsules as a carrier oil, and as a purified component of some intravenous nutrition (lipid) products given in hospitals.

Soybean oil is rich in polyunsaturated fatty acids. The main one is linoleic acid, an omega-6 fat, and it also has some alpha-linolenic acid, an omega-3 fat. These are "essential" fats, meaning the body needs them from the diet.

Replacing saturated fats with unsaturated fats like those in soybean oil may help improve blood cholesterol levels, which is the proposed reason for its heart-related benefits.

The oil also contains vitamin E (an antioxidant) and phytosterols, plant compounds that may modestly affect cholesterol absorption. Much of the detail on how these compounds act comes from laboratory and animal research, so the real-world effect of soybean oil as a supplement is not fully proven.

Soybean oil is widely eaten and is generally safe for most people as part of a normal diet. Because it is highly processed, refined soybean oil contains very little soy protein, so many people with soy allergy can tolerate it—but this is not guaranteed.

Soy allergy: If you have a soy allergy, talk to your doctor before using soybean oil products, especially cold-pressed or less-refined oils that may contain more protein.

Calories and weight: Soybean oil is high in calories and fat. Using large amounts can add a lot of calories to your diet.

Pregnancy and breastfeeding: Eating soybean oil in normal food amounts is considered safe during pregnancy and breastfeeding. Taking concentrated supplement doses has not been well studied, so it is best to stick to food amounts and check with your doctor.

As with any supplement, talk to a pharmacist or doctor before taking soybean oil capsules for a health condition.

Soybean oil eaten as food usually causes no side effects in most people. Taking large amounts of oil or oil-based supplements may cause stomach upset, loose stools, or a greasy feeling.

People with a soy allergy could have an allergic reaction, although highly refined oil is less likely to trigger one. Stop use and seek medical care if you notice signs of an allergic reaction such as hives, swelling, or trouble breathing.

Because it is calorie-dense, frequent use of large amounts can contribute to extra calorie intake over time.

There is no official standardized supplement dose of soybean oil. As a food, it is used in normal cooking amounts, and as part of a healthy diet experts generally suggest replacing saturated fats with unsaturated oils rather than simply adding more oil.

For supplement products such as softgels, follow the directions on the product label. Intravenous soybean-oil lipid products are dosed only by healthcare professionals in a medical setting.

If you are considering soybean oil for a specific health reason, talk with your pharmacist or doctor about whether it is appropriate and how much to use.