Trans fat Substitutes May Increase Blood Sugar

February 24, 2007

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Trans Fat Substitutes May Increase Blood Sugar

Feb. 9 (iVillage Total Health) -- As many restaurants and cooks rush to take artery-clogging trans fatty acids from their menus, researchers have found that some of the replacement fats may increase blood sugar. Results of the study, which was conducted in part by researchers at Brandeis University in Massachusetts and the Malaysian Palm Oil Board, were published online in the January 15 issue of Nutrition & Metabolism. Researchers used 30 volunteers for the four-week study, which involved feeding them meals from diets prepared with one of three different cooking oils. Each subject eventually consumed meals from all three diets. The first diet used palm olein, a saturated fat derived from palm oil. The second used a blend of 30 percent soybean oil, 30 percent palm olein and 40 percent partially hydrogenated soybean oil. The third oil used interesterified fat, prepared by chemically modifying molecules in soybean oil and palm olein through a process called interesterification. Researchers noted that interesterification is a new method of modifying fats in commercially sold cooking oils that replaces unhealthy trans fatty acids -- known more commonly as trans fats. These fats are the basis of the lards, spreads and cooking oils used to prepare foods. Trans fats are produced when hydrogen is added to vegetable oil. This process - called hydrogenation -- makes some foods, particularly baked and fried goods, tastier and keeps them fresher for longer periods of time on store shelves. Trans fats raise the low-density lipoprotein (LDL) blood levels in the body. LDLs are the bad cholesterol responsible for clogging arteries and causing strokes and heart attacks . Trans fats also reduce the level of good cholesterol (high-density lipoprotein or HDL) in the blood. A 2006 study conducted by the Harvard School of Public Health showed a link between trans fats and an increased risk of coronary artery disease and other serious conditions. Many fast food restaurant chains (including McDonald's, KFC, Taco Bell and Wendy's International) have replaced or are replacing trans fats in cooking oils with healthier unsaturated fats , such as olive, canola, soybean, corn or sunflower oils. For the Malaysian study, volunteers were served three catered meals a day prepared under the direction of a dietitian. None of the participants reported family or personal histories of atherosclerosis or hypertension and none reported using tobacco, alcohol or weight loss medications. Researchers took blood samples before, during and after the test period for levels of total cholesterol, low-density lipoproteins, high-density lipoproteins, triglycerides and blood sugar. They found that the interesterified fats adversely affected metabolism of lipoproteins and glucose compared to the soybean oil or palm olein. "In this study we discovered that trans fat also has a weak negative influence on blood glucose," researcher K.C. Hayes said in a press release. "The newer replacement for trans fat, so-called interesterified fat, appears even worse in that regard, raising glucose 20 percent in a month." Researchers said further studies were needed on the insulin metabolism with the new fats and to determine if the effects they observed were unique to the Malaysian population they studied. Copyright 2007 iVillage Total Health. Publish February 09, 2007