Iron Involved in LDL Oxidation
Researchers from the Baylor College of Medicine have discovered that iron is involved in the process of oxidation of low-density lipoproteins, also known as LDL. The oxydation of LDL and high levels of LDL-cholesterol in the bloodstream have been linked to artery damage known as atherosclerosis, also called the hardening of the arteries. Hardening of the arteries is the leading cause of cardiovascular disease, which includes coronary artery disease, heart attacks, strokes and other blood vessel diseases.
The Baylor researchers found that the LDL oxidation process utilized iron ions and produced kyurenines on the surface of the oxidized LDL particles. Kyurenines have been associated with a number of inflammatory and degenerative disorders, including Alzheimer’s, dementia, malaria, Huntington’s disease, cancer, ALS, depression and schizophrenia. The oxidation process also produced and increase in tryptophan. Imbalances between tryptophan and kyurenines have been seen in the above diseases.
The researchers also reviewed epidemiological research that suggested that iron serves as a catalyst in the progression of atherosclerosis.
LDL-cholesterol has been found more prevalent in diets higher in fried foods, trans-fats, red meats and saturated fats. Red meats also provide significant levels of iron.
While the research has not concluded that dietary iron stimulates higher levels of LDL-oxidation, it is apparent that the oxidation process requires iron.
Iron overload, or hemochromatosis, can cause iron deposits to form within various tissues and organs around the body. Iron deposits within the pancreas can shut down insulin production, producing diabetes. A built up of iron in heart tissue can produce arrhythmia and heart failure. The build up of iron in the liver produces cirrhosis and increases the risk of liver cancer. Now it could be hypothesized from this research that high iron levels may well increase LDL oxidation.
Chen HH, Chen CY, Chow LP, Chen CH, Lee YT, Smith CV, Yang CY. Iron-catalyzed oxidation of Trp residues in low-density lipoprotein. Biol Chem. 2011 Aug 18.
Chen Y, Guillemin GJ. Kynurenine Pathway Metabolites in Humans: Disease and Healthy States. Internl Jnl Trypt Res. 2009:2 1-19.