A popular form of vegetable oil, soybean oil is extracted from the seeds of the soybean. There has been much hype about it being a healthful oil, but there’s more to soybean oil than what’s advertised on product labels. It could be very problematic to use in cooking, due to factors such as hydrogenation and the presence of genetically engineered varieties. Get the lowdown on this polyunsaturated oil — and why it is one of the worst oils for cooking.
What Is Soybean Oil?
Soybean oil is extracted from the soybean (Glycine max) and often has a dark yellow or faint green color. Standard vegetable oil is typically composed of soybean oil. 1
The first domestic use of soybean is traced to the eastern half of North China in 11th BC, or perhaps a little earlier.2 Soybean is one of the five main plant foods of China, along with rice, wheat, barley, and millet. Early accounts have it that soybean production was localized in China until after the China-Japan War of 1894 to 1895, when the Japanese started to import soybean oil cake as fertilizer.
Soybean shipments to Europe were made in around 1908, although Europeans had been aware of soybeans as early as 1712 through a German botanist’s writing. In U.S. literature, the first use of the word “soybean” was in 1804. Most of the early U.S. soybeans were used as a forage crop instead of being harvested for seed.
Today, Americans consume more than 28 billion pounds of edible oils annually, and soybean oil accounts for about 65 percent of the said figure. Mexico and Korea are large customers of U.S. soybean oil.
Unfortunately, about half of the soybean oil used in the country is hydrogenated, as soybean oil is too unstable to be used in food manufacturing. Among the problems with partially hydrogenated soybean oil is trans fat and the health hazards of the soy itself, as well as the prevalence of genetically engineered soybeans today.
Uses of Soybean Oil
Soybean oil is processed and sold mainly as a vegetable oil, while the remaining soybean meal is typically used as animal feed.3 It is also the primary source of biodiesel in the country, making up 80 percent of domestic production.4
Lecithin is a product extracted from soybean oil, and it is a natural emulsifier and lubricant used in many foods and commercial and industrial applications. It helps keep the chocolate and cocoa butter in a candy bar from separating, and is used in pharmaceutical products and protective coatings.5
Soybean oil is commonly used to make mayonnaise, salad dressing, margarine, and non-dairy coffee creamers. It is a usual feature of processed foods, which is where the problem begins: processed foods are perhaps the most damaging part of most people’s diet, contributing to the occurrence of disease and poor health.
Partially hydrogenated soybean oil is one of the primarily culprits in processed foods, alongside high fructose corn syrup (HFCS). Used alone or in combination, they spell trouble for your wellness. But why is there a need to hydrogenate oil? One of the most common answers you hear is that it prolongs the oil’s shelf life.6 For example, raw butter is likely to go rancid far more quickly than margarine does.
Hydrogenation — where hydrogen gas is forced into the oil at high pressure — also makes the oil more stable and increases it melting point, allowing it to be useful in various food processing methods that use high temperatures.
In the late 1990s, experts started to see and confirm the adverse health effects of this chemical alteration. Beware, though, that “fully hydrogenated” is different from “partially hydrogenated.” The latter contains trans fat, while the former does not. But this does not make fully hydrogenated soybean oil a healthful choice.
Composition of Soybean Oil
Within soybean oil are four phytosterols: stigmasterol, sitosterol, campestrol, and brassicasterol.
Per 100 grams of soybean oil, there is about 16 grams of saturated fat, 23 grams of monounsaturated fat, and 58 grams of polyunsaturated fat.7 Of the unsaturated fatty acids, linoleic acid, a type of omega-6 fat, is about 50 percent, while linolenic acid is about seven percent.
Leading biotech company Monsanto has come up with soy crops as a response to the growing demand for healthier diets. Its Vistive low-linolenic soybeans,8 for instance, was launched in 2005 and contain only one to three percent linolenic acid. Therefore, according to Monsanto, “the oil produced … does not require hydrogenation.”
Yet another soybean variety it created is the high stearate soybean, which retains the properties of margarine and shortening without hydrogenation. Given the separate issue of GMO safety, I don’t think these are options worth taking.
Benefits of Soybean Oil
Perhaps the main benefits of soybean oil are for food manufacturers, who are able to use cheap vegetable oils for their products. It took many years before conventional health authorities to finally warn against using trans fat.
The Food and Drug Administration (FDA) required food manufacturers to list trans fat content on the label starting January 1, 2006 — a move that essentially allows some companies to fool buyers, as any product containing up to half a gram of trans fat per serving can still legally claim to contain zero trans fat.9 It turns out that the trick is to reduce the serving size to bring it below this threshold.
How to Make Soybean Oil
Soybean contains about 19 percent oil. To extract soybean oil from the seed, the soybeans are cracked, adjusted for moisture content, rolled into flakes, and solvent-extracted with commercial hexane. Afterwards, the oil is refined and blended for various applications — and often hydrogenated.10
It is often that commercial brands mix soybean oil with cheaper ones to make the end product more affordable. But there are unrefined soybean oil products, cold-pressed and expeller-removed. They usually have a stronger flavor, but are said to retain a higher nutritional value than refined oils.
How Does Soybean Oil Work?
The partial hydrogenation of soybean oil creates completely unnatural man-made fats, which can cause dysfunction and chaos in your body on a cellular level. Proceed to the section below for safety issues with soybean oil, particularly with the presence of trans fat.
Is Soybean Oil Safe?
Research has associated trans fat,11 an unnatural fat present in partially hydrogenated soybean oil, with:
- Cancer, through interfering with your body’s cancer-fighting enzymes
- Diabetes, through interfering with the insulin receptors in your cell membranes
- Heart disease, through clogging your arteries (In women with underlying coronary heart disease, consuming trans fats increased the risk of sudden cardiac arrest three-fold)
- Chronic problems such as obesity, asthma, autoimmune disease, and bone degeneration
- Decreased immune function
- Reproductive problems, by interfering with sex hormone-producing enzymes
- Increased blood levels of LDL or “bad” cholesterol, and lowered levels of HDL or “good” cholesterol
- Interfering with how your body uses beneficial omega-3 fats
Besides these risks, soybean oil in and of itself is NOT healthy. Its fat is primarily omega-6 fat, which we do need in certain amounts but is way too pervasive in the standard diet. Its omega-6 is also highly processed and therefore damaged, and promotes chronic inflammation in your body — the hallmark of virtually all chronic diseases.
Genetically engineered soybean oil is the worst offender. GE soybeans are linked to significant adverse health effects, including increased infertility rates with each passing generation. But even if you have organic soybean oil, it still poses several significant issues, including the following problems with soy:
- Goitrogens – Substances that block the synthesis of thyroid hormones and interfere with iodine metabolism.
- Isoflavones: genistein and daidzein – A type of feminizing phytoestrogens, and are shown by evidence to disturb endocrine function, cause infertility, and promote breast cancer.
- Phytic acid – These bind to metal ions and prevent the absorption of certain minerals, including calcium, magnesium, iron, and zinc. Soybean has one of the highest phytate levels of any grain or legume, and its phytates are highly resistance to normal phytate-reducing methods such as long, slow cooking. Only a long fermentation period will substantially reduce soybeans’ phytate content.
- Anti-nutrients – These are natural toxins such as saponins, soyatoxin, protease inhibitors, and oxalates. Some of these interfere with the enzymes you need to digest protein. These anti-nutrients are not problematic in small amounts, but Americans today are consuming too much soy.
- Hemagglutinin – A clot-promoting substance that causes your red blood cells to clump together, with the cells unable to properly absorb and distribute oxygen to your tissues.
Side Effects of Soybean Oil
Beware of soy allergy, which can also happen in very young infants fed soy-based formula. Allergic reactions may also manifest when consuming the oil.
Through the risks and negative effects I’ve outlined above, I want to make it clear that you are better off avoiding soybean oil and other vegetable oils for cooking, as well as totally eliminating processed foods from your diet. This way you can avoid dangerous fats of all kinds, mostly trans fat coming from partially hydrogenated soybean oil.
I highly recommend coconut oil for cooking, as it is far superior to any other cooking oil and is loaded with healthful properties. Use organic butter (preferably made from raw milk) instead of margarines and vegetable oil spreads. Butter does not deserve a bad rap, as it offers an array of wholesome benefits.
A good nutrition plan will automatically reduce your trans fat intake, putting the focus on healthy, whole, raw foods instead of the processed junk you are using to getting at the supermarket. Remember that virtually all processed foods are guaranteed to contain either HFCS or soybean oil, or both.