Low levels of high-density lipoprotein (HDL or "good") cholesterol and an antioxidant called glutathione peroxidase may increase a person's risk of dying from heart disease, a study reports.
Researchers analyzed samples from 130 people who participated in the Minnesota Heart Survey, all of whom had died of heart disease during the five to 12-year follow-up. All participants ranged in age from 26 to 58 and had provided information on HDL levels, glutathione peroxidase levels, and other measures of health such as exercise, smoking status and alcohol intake.
People who had both low levels of HDL and low levels of glutathione peroxidase appeared to have the highest risk of dying from heart disease, the results suggested.
The researchers concluded that both cholesterol levels and antioxidant status might be linked to heart disease mortality risk.
Cholesterol and other fats cannot dissolve in the blood. They have to be transported to and from the cells by special carriers called lipoproteins. There are two main types of lipoproteins, including low-density lipoprotein (LDL, or "bad") cholesterol and high-density lipoprotein (HDL, or "good") cholesterol. Another type, very-low-density lipoprotein (VLDL) is converted to LDL in the bloodstream. Each form of lipoprotein contains a specific combination of cholesterol, protein, and triglyceride (a blood fat). VLDL cholesterol contains the highest amount of triglyceride.
Too much LDL cholesterol can block the arteries, increasing the risk of heart attack and stroke. LDL takes cholesterol into the bloodstream, and HDL takes it back to the liver for storage. It is also believed that HDL removes excess cholesterol from plaque in arteries, thus slowing the buildup. Studies suggest that high levels of HDL cholesterol reduce the risk of heart attack.
Buijsse B, Lee DH, Steffen L, et al. Low Serum Glutathione Peroxidase Activity Is Associated with Increased Cardiovascular Mortality in Individuals with Low HDLc's. PLoS One. 2012;7(6):e38901. Epub 2012 Jun 15.