A dose of fiber every day won't make up for a high-fat diet, if a study on rats by UC Davis nutritionists is any indication. A high-fat diet supplemented with fiber may not increase cholesterol levels, but it may boost fat in the bloodstream in the form of triglycerides. People eating high-fiber diets naturally tend to decrease their fat intake. However, if they simply take a fiber supplement while continuing to eat a high-fat diet, they may still be contributing to high concentrations of fat in the bloodstream. "We've been looking at how the intestine adapts to fiber," says graduate student Suzette Middleton. "It has been suggested that, with a high dietary fiber intake, the lower third of the small intestine is more involved with nutrient and fat absorption than with a low fiber intake." To test whether this happens in an animal model, Middleton and Professor Barbara Schneeman fed 40 rats either high-fat diets or low-fat diets, each containing 6 percent oat bran fiber. They found that adaptation to the high-fat diets with bran fiber did not affect the rats' cholesterol levels. However, triglycerides in the bloodstream were significantly higher after a high-fat test meal than after a low-fat test meal, both containing oat bran. Overall, the results indicate that adding oat bran to a high-fat diet does not prevent the body from absorbing excess calories from fat. The paper will be presented at the nutrition minisymposium titled "Lipid Absorption and Transport," Monday, April 6, 2:45 p.m., Anaheim Convention Center, Room A7.