You know that trans fats are out…so no more partially hydrogenated soybean oil. But in recent years, the food industry has genetically engineered soybean oil to be more like healthful olive oil. It’s “shelf stable” (exactly what “Big Food” wants) without hydrogenation, so no trans fats. And it’s appearing in more and more of the food you buy. But is soybean oil that’s made to be more like olive oil good for you? Better than coconut oil? New research focuses on the possible effects on weight gain and diabetes, two emerging concerns with our cooking oils. The answers may surprise you…and motivate a quick oil change in your kitchen.
The latest approach is to genetically modify soybean oil so that it contains more oleic acid—the monounsaturated fatty acid found in large amounts in olive oil—to make a healthier, inexpensive, shelf-stable oil. What if this new GMO soybean oil weren’t just good for business but also good for health?
Soybean oil, while relatively new to the human diet, is now the predominant oil in American food. It’s everywhere, from salad dressings to baked goods to condiments and snacks—not to mention that big bottle of soybean cooking oil that you may have on your kitchen shelf. It’s cheap (no wonder it’s everywhere). But because regular soybean oil is so high in polyunsaturated fats, it goes rancid quickly. Hydrogenation, which keeps it from going rancid but creates trans fats, was a major health fiasco. Even without the trans problem, regular soybean oil has been losing some of its healthful glow in some circles. Some researchers have even suggested that soybean oil in general, and its primary fat linoleic acid in particular, may be contributing to obesity and diabetes.
To look at these health questions, researchers fed mice one of four diets for six months. One was a very low-fat diet (5% of calories) known to minimize weight gain and reduce diabetes factors. It was compared with high-fat diets (40% of calories) rich in regular soybean oil, high-oleic-acid GMO soybean oil or coconut oil.
Result: The mice fed either kind of soybean oil gained significantly more weight, had fattier livers and had more glucose intolerance (a diabetes risk factor) than either controls or coconut oil eaters. Those fed GMO soybean oil gained less weight and had less insulin resistance (another diabetes risk factor) than those fed regular soybean oil—good news for the bioengineered stuff—but the effects on weight and the liver were still negative. Maybe it’s something in soybean oil other than linoleic acid that’s a problem, the researchers speculate.
The coconut oil–fed mice did better, gaining only slightly more weight than controls on the super-low-fat diet. Researcher Poonam Jot Deol, PhD, from the department of cell biology and neuroscience at University of California, Riverside, explained that coconut oil contains medium-chain fatty acids that are metabolized more quickly than other fatty acids, so it may contribute less to weight gain, including belly fat.
This study has nothing to do with GMO issues, since almost all soybean oil in this country is already GMO. And the study results have nothing to do with soy foods in general. They are nutritionally very different from the highly processed oils extracted from soybeans.
Nor does this study mean that you should leap on the coconut oil bandwagon yet. Coconut oil is high in saturated fat, and while healthier than we once thought, it’s not a perfect oil.
What’s best for your kitchen? The researchers themselves believe that coconut oil is a healthy choice, and that extra-virgin olive oil may be even healthier. The researchers used coconut oil in this study because it’s naturally low in linoleic acid, making the study design easier, but they plan to compare olive oil with GMO-modified soybean oil in their next study. Extra-virgin olive oil is not only rich in oleic acid and low in linoleic acid, but is also extracted under low-heat conditions that preserve healthful antioxidant compounds. (For more about healthy fats, see Bottom Line’s “Butter is Bad for You and Other Lies”.)
Dr. Deol’s personal recommendations? Cook at home more so you are in control of what you eat…use olive oil or coconut oil…and be conscious of the amount of fat or oil you use. Too much of even a “good” oil is still too much.
