Consumers know that bad cholesterol is bad for the heart, but good cholesterol can be bad in terms of heart health too, says a new study by the Cleveland Clinic. Good cholesterol is also known as high-density lipoprotein (HDL.) It turns bad once it is oxidized in the arteries. The nature of the protein changes and it can become just as harmful as bad cholesterol, low-density-lipoprotein (LDL.) This isn’t always the case, but the discovery of abnormalities shows that it can happen.
For decades, the risks associated with consuming excessive amounts of bad cholesterol have been clear; they pose a clear danger and put people at risk for heart disease. Foods like eggs, dairy, fast food and fried foods pose a risk for heart attacks and stroke. Warnings have been issued to reduce the intake of these foods and increase the intake of foods that are high in HDL.
What wasn’t clear until recently, was the effect of foods that contain good cholesterol. HDL has been touted as a way to reduce bad cholesterol. Foods high in HDL, such as olive oil, avocados, beans, lentils, fish, onions and garlic, are said to improve heart health. The results of a Cleveland Clinic study were recently published in Nature Medicine, an online news source. The report claims that good cholesterol turns bad once it is oxidized.
HDL is complicated, because while it is usually sent directly to the liver without a chance to attach to the artery walls, some of it is able to get back up through the bloodstream and cause problems. It can then leave deposits on the artery walls that build up over time, which can restrict blood flow; this makes it just as dangerous as bad cholesterol.
Good cholesterol contains a protein called apoliproprotein (apoA1). In normal circumstances, this protein is what gives the cholesterol its protective properties. According to the Cleveland Clinic, the good cholesterol changes to bad, when the apoA1 is oxidized while in the artery wall. That change is what interests researchers.
Dr. Stanley Hazen is the Vice Chair of Translational Research for the Lerner Research Institute at the Cleveland Center. He and his colleagues spent five years studying the nature of good cholesterol and how it changes to create health risks. They tested 627 participants who had raised HDL levels and were at risk for heart disease.
The team found that participants who had a higher level of apoA1, also had a higher risk of heart disease. The results of the study prompted researchers to develop a test to check for abnormal HDL, then create drugs to treat the abnormality, thereby preventing damage to the heart. Finding out what causes the dysfunctional protein is the first step; creating a medical treatment, is the next. Both are key to maintaining a healthy heart while consuming foods that are high in HDL.
Hazen’s message to the public to “eat foods high in good cholesterol” remains unchanged, even in light of the findings from the Cleveland Clinic. The study on proteins should not be taken as a sign to reduce the amount of good cholesterol people eat. It is only the abnormal apoA1 proteins that are problematic. The Cleveland Clinic says that early detection and treatment will take priority, when scientists are able to develop a test to identify the good cholesterol, once it turns bad.
By Tracy Rose