A popular form of vegetable oils, soybean oil is extracted from soybean seeds.1 There has been much hype about its touted health benefits, 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 manufacturing processes and the presence of genetically engineered varieties. Get the lowdown on this food staple, and why it is one of the worst oils for cooking.
Soybean oil is extracted from soybean (Glycine max) and often has a dark yellow or faint green color. Standard vegetable oil is typically composed of soybean, corn, safflower and palm oils.2
The first domestic use of soybeans is traced to the eastern half of North China in the 11th century B.C., although as early as 2853 B.C., the plant was considered a sacred plant of China along with rice, wheat, barley and millet. By 1895, Chinese soybean production expanded overseas when the Japanese began importing soybean meal to serve as fertilizer.3
Soybean shipments to Europe began around 1908, although Europeans had been aware of soybeans as early as 1712. The story of soybeans in the United States began in the early 1800s, with North Carolina having one of the first soybean plantations.4
As of 2016, Americans were consuming more than 28 billion pounds of edible oils annually, with soybean oil comprising about 80 percent of that number. Worsening the problem further at the time was that soybean oil was highly processed and hydrogenated.5
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. According to the U.S. Department of Agriculture (USDA), 94 percent of soybeans today are grown using herbicide-tolerant seeds.6
Thankfully, in an effort to address health concerns that partially hydrogenated oils (PHOs) — the primary dietary source of trans fats — could be causing thousands of heart attacks and deaths each year, the FDA decided in 2015 that PHOs no longer should be considered "generally recognized as safe (GRAS), and started a campaign wherein food manufacturers were given three years to phase out trans fat from their products, with the ban officially taking effect on June 18, 2018.
This marked a turning point for public health, as The Washington Post reported that trans fat consumption soon drastically lowered. Between 2015 and 2018, companies were able to remove 98 percent of trans fat from the market.7 Later, in a gesture to allow what they called "an orderly transition in the marketplace," the U.S. Food and Drug Administration extended the date for these foods to get completely off grocery store shelves to January 1, 2020.8
Uses of Soybean Oil
The USDA notes that processed soybeans are the second largest source of vegetable oil — close behind palm oil — as well as the largest source of protein for animal feed.9 It is also the primary source of biodiesel in the country, making up 52 percent of domestic production.10
Lecithin, a product extracted from soybean oil, is a natural emulsifier and lubricant used in many foods, as well as commercial and industrial applications. As an emulsifier, it helps products maintain a smooth quality because it binds two disparate chemicals together.11
Soybean oil is commonly used to make mayonnaise, salad dressing, margarine and nondairy coffee creamers.12 It is also a mainstay ingredient in many processed foods, which is where the problem begins: Processed foods are perhaps the most damaging part of most people's diets, contributing to the occurrence of disease and poor health.
Partially hydrogenated soybean oil was one of the primary culprits in processed foods because of its trans fat content, a substance that can damage your health by increasing your LDL cholesterol levels while simultaneously lowering HDL cholesterol levels, as well as causing a host of other health-related concerns.13
But since the banning of trans fat, companies have been looking for new ways to produce "healthier" soybean oil, such as making it from high-oleic soybeans. These specially made soybeans were created to not need to undergo hydrogenation when processed; thus, no trans fats are formed.14 Oleic acid, such as the that found in olives, has been linked to lowered risk of heart disease.15
However, be aware that high-oleic soybeans are genetically modified, such as Monsanto's Vistive Gold (MON 8775).16 According to a report published by GenØk, a Norwegian foundation that monitors safe consumption of biotechnologies, review officials assert that Monsanto is not entirely honest about their claims about their product's benefits.
The report cites improper assumptions, weakness in study design, lack of information on potential adverse events and improper use of comparators as some of the major concerns, concluding that the company should provide more information to properly assess the risk of MON8775 to public health.17