Scientists at Washington University School of Medicine in St. Louis have identified a substance in the liver that helps process fat and glucose. That substance is a component of the common food additive lecithin, and researchers speculate it may one day be possible to use lecithin products to control blood lipids and reduce risk for diabetes, hypertension or cardiovascular disease using treatments delivered in food rather than medication.
"Currently, doctors use drugs called fibrates to treat problems with cholesterol and triglycerides," says the study's co-first author Irfan J. Lodhi, Ph.D., a post-doctoral fellow in endocrinology and metabolism. "By identifying this substance that occurs naturally in the body - and also happens to be used as a food additive - it may be possible to improve the treatment of lipid disorders and minimize drug side effects by adding particular varieties of lecithin to food."
Lecithin is found at high concentrations in egg whites. It also is in soybeans, grains, fish, legumes, yeast and peanuts. Most commercially used lecithin comes from soybeans. Lecithin can alter food taste and texture and also can be mixed with water to disperse fats, making it a common additive in margarine, mayonnaise, chocolate and baked goods. Lecithin is a mixture of fatty compounds called phosphatidylcholines. Various types of phosphatidylcholines house different kinds of fatty molecules linked to a common core.
This new study demonstrates that in the liver, a specific type of lecithin binds with a protein called PPAR-alpha, allowing PPAR-alpha to regulate fat metabolism. Scientists long have known that PPAR-alpha is involved in lipid and glucose metabolism. When doctors prescribe fibrate drugs to lower triglycerides and elevate good cholesterol in the blood, those drugs work by activating PPAR-alpha.
Although fibrates activate the protein, no one previously had identified any naturally occurring substance that could perform that task. Reporting in the Aug. 7 issue of the journal Cell, the Washington University research team describes how it found the link between lecithin and PPAR-alpha.
They first created a strain of mice that could not make fatty acid synthase in the liver. When humans or animals eat, we take in sugars. Fatty acid synthase converts those sugars to fatty acids in the liver, where they play important roles in energy metabolism.