It sounds like a junk-food junkie's dream come true--a fat substitute with no calories and no fat. But while olestra recently won approval form the Food and Drug Administration for use in salty snacks, UT Southwestern nutrition experts who were involved in some of the early studies on the fat substitute don't necessarily consider it a victory. Olestra, manufactured by Procter & Gamble, is a synthetic compound of sugar and vegetable oil. It adds no fat or calories to food because the olestra molecule is bigger than ordinary fat molecules and passes through the body without being absorbed.
Olestra itself, however, interferes with the absorption of fat-soluble vitamins A, D, E, K and some carotenoids. Carotenoids are believed to be important in warding off cancer. Procter & Gamble has agreed to boost the level of the vitamins in their food to counteract some of that absorption. FDA Commissioner David Kessler said olestra does cause abdominal cramping and diarrhea in some people, so products containing the fake fat will have to carry a warning label. While most people have only recently heard of olestra, it is not new. It has been studied and debated for two decades.
Dr. Scott Grundy, director of the Center for Human Nutrition, conducted early research on olestra and in 1986 reported that it showed promise in treating obesity and diabetes. Ten patients--three diabetics, three diabetics with high triglycerides and four nondiabetics--lost weight and experienced a decrease in their total cholesterol and low-density lipoprotein (LDL) cholesterol when placed on a calorie-restricted diet with olestra. Most of the diabetic patients were unable to tolerate as much olestra as the other patients because large amounts resulted in abdominal discomfort or diarrhea. Smaller amounts were well-tolerated.
Today, Dr. Grundy is hesitant to endorse its universal use. "I think if used appropriately in the right people, it could have benefits--specifically lower cholesterol and weight reduction," he said. "Obesity is a subject of great concern to our researchers. Olestra could be one step in the treatment of obesity, but I would prefer that it be used under a physician's guidance." Dr. Grundy would have preferred that olestra be tested further as a cholesterol-lowering or weight-control drug--so that any side effects could be carefully monitored--before being released to the general public. In the meantime, he said, it could be used for treating patients with specific nutritional problems.
Some researchers say that because it has been approved for only snack foods, olestra will have little impact on health and nutrition. Olestra products will be fat-free but not calorie-free. These snacks will have about half the calories of regular chips and crackers. In the future, olestra could be used to replace fats in shortenings and oil, ice cream, table spreads, salad dressings and cheese, but any use beyond snack chips will require separate FDA review and approval.
