There is a dynamic interplay between cholesterol and your immune system. If studies recent to 2011 are correct, cholesterol and the immune system react with each other to try and prevent the spread of infection. Scientists are pondering whether cholesterol-lowering drugs could stimulate the immune system and fight disease—and whether immune system adjustments could prevent cardiovascular events like heart attacks, which are associated with high cholesterol.
Healthy Immune Systems Suppress Cholesterol
Scientists from the University of Edinburgh reported in the March 2011 journal “PLoS Biology” that they found a link between the immune system and cholesterol levels. They found that when a healthy immune system is attacked by a virus, it innately responds by suppressing the synthesis of cholesterol. They said infections such as a virus need cholesterol to spread, and it’s possible that high cholesterol may play a role in a weakened immune system. They suggested that cholesterol-lowering drugs may boost the immune system.
Immune System Regulates Blood Lipids
Four years before the Edinburgh study, University of Chicago researchers published findings in the journal “Science” that the immune system directly influences lipid metabolism—the development, use and removal of cholesterol, triglycerides and other blood fats. Their study used mice, some with altered LDL cholesterol receptors. The scientists looked specifically at T cells, which play a role in immunity. By changing the way certain molecules acted on T cells, the researchers significantly changed the mice’s cholesterol and triglyceride levels. They described the results as unexpected, because they suggested that engineered immune system cells could possibly prevent high cholesterol and triglycerides. That means the immune system could be tweaked to possibly prevent coronary heart disease.
Contradictory Findings
Dr. Joseph Mercola, the controversial doctor of osteopathic medicine, said the answers to the Edinburgh questions have already been proven in study from a 2000 issue of “Nature Medicine.” In reviewing the study, Mercola wrote that cholesterol-lowering drugs “Lipitor, Mevacor and Pravachol have been found to suppress certain immune system cells known as helper T-cells.” The study suggested a new role for these drugs as immune system suppressants for patients undergoing organ transplant. Mercola called that recommendation a positive spin on a study that had a poor result. Mercola has long been critical of cholesterol-lowering drugs, saying they were overprescribed, not very effective and possibly promoted because of their profitability. He claims the last thing someone with high cholesterol needs is a drug that suppresses his immune system.
Cholesterol and Inflammation
Scientists are interested in cholesterol because as the bad form of it builds up in your blood vessels, plaques form and block your arteries. This increases your risk of heart attack and stroke. However, in reports on various studies, Time magazine and CNN report that many people who have heart attacks have normal cholesterol levels. In 2011, researchers are convinced that inflammation—a response of your immune system—is like cholesterol’s partner in crime. Inflammation is the unleashing of immune system cells and chemicals that attempt to fight off an infection. Many people who have immune-related disorders, like lupus and rheumatoid arthritis, also have cardiovascular problems, too. One way doctors get a read on inflammation is by measuring a substance called C-reactive protein, or CRP. A group of researchers found that when people with normal cholesterol but high CRP took cholesterol-lowering medications, their risk of heart attack dropped significantly.
References
- “PLoS Biology”; Host Defense against Viral Infection Involves Interferon Mediated Down-Regulation of Sterol Biosynthesis; Mathieu Blanc et al.; March 2011
- “Science”; Lymphotoxin ß Receptor–Dependent Control of Lipid Homeostasis; James C. Lo et al.; April 13, 2007
- “Nature Medicine”; Immunomodulation: A New Role for Statins?; Wulf Palinski; 2000
- "Huffington Post"; The Cholesterol Myth That Could Be Harming Your Health; Joseph Mercola; Aug. 12, 2010
- University of Chicago Medical Center; Link Found between Immune System and High Plasma Lipid Levels; April 12, 2007
- “New England Journal of Medicine”; Rosuvastatin to Prevent Vascular Events in Men and Women with Elevated C-Reactive Protein; Paul M Ridker et al.; Nov. 20, 2008
