In one study, researchers looked at 30 healthy volunteers who agreed to follow three different diets for four weeks each. Each of the three diets emphasized a different type of fat: trans fats, interesterified soybean oil and a natural, saturated fat. The participants’ cholesterol and blood sugar levels were measured before beginning eat diet and at the end of each four-week period.
While on the diet with trans fats, the participants’ LDL levels rose, as expected. However, when the participants ate the diet featuring interesterified fat, their blood sugar rose 20 percent and their HDL levels dropped as compared to when they ate the diet featuring the saturated fat.
Hayes believes that interesterified fats change the levels of insulin in the body. This hormone helps regulate blood sugar levels, and if it is not working right, people are at risk for diabetes.
“There is very strong evidence of the association between trans fats and diabetes, but now we have some evidence that interesterified fats also increase your risk,” said Dr. K. C. Hayes, study author from Brandeis University in Waltham, Massachusetts.
While more work needs to be done to determine their true health risk, interesterified are currently being used to replace trans fats. To avoid both trans fats and interesterified fats, Hayes recommends closely looking at nutrition labels. Just because a box of cookies says it’s “trans-fat free” does not mean it’s healthy.
Hayes recommends that consumers look to see if a fat is listed with any words in front of it. Words like “partially hydrogenated oil” signal the use of trans fats, and “fully hydrogenated oil” on the ingredients list is another word for interesterified fats.
The best bet is to look for food that just lists the oil used as it is found in nature: olive oil, canola oil, vegetable oil.
