Do you know what triglycerides are?
Triglycerides are that number included at the end of every cholesterol panel. You know, the one your doctor usually ignores and most people don't even know is there.
What exactly does this neglected value mean?
Triglycerides are a basic building block for the very first cholesterol-containing particle produced by the liver, building blocks of very low-density lipoprotein particles, or VLDL. The more that triglycerides are available, the more VLDL the liver produces.
After emerging from the liver, VLDL particles undergo a series of interactions in the blood. One path transforms VLDL into LDL cholesterol particles. More triglycerides means more VLDL, which then means more LDL.
It gets even trickier. If excess triglycerides are available, more VLDL is produced which, in turn, encounters LDL and HDL particles in the blood. Triglycerides from VLDL are transferred onto LDL and HDL, which become bloated with triglycerides as a result. Triglyceride-bloated LDL and HDL are reconfigured into smaller versions, small LDL and small HDL. Both small LDL and HDL are undesirable particles that stimulate plaque growth.
Thus, excess triglycerides and VLDL are behind the creation of small LDL and small HDL. Small LDL are at least three-fold more potent in causing heart disease. Small HDL renders this otherwise beneficial particle ineffective. Small is bad.
So, not only do triglycerides and VLDL precede the formation of LDL particles, they also determine the composition of LDL particles, as well as HDL. You might say that triglycerides are therefore the mother of most cholesterol particles in the blood.
So what causes excessive triglycerides?
Curiously, while excessive triglycerides usually are associated with heightened risk for heart disease, this is not always true, particularly in some people with a genetic cause for high triglycerides (familial hypertriglyceridemia). These situations can only be distinguished by your doctor (or a lipid expert).
In the real world, the majority of people with high triglycerides have gotten that way through lifestyle mistakes. Triglycerides are high (>100 mg/dl to 400 mg/dl) usually due to excess weight and indulging in processed carbohydrates. You might even say that triglycerides can serve as a useful index of your processed carbohydrate intake and can parallel blood sugar.
Triglycerides are an important risk factor for coronary plaque growth, even at levels previously thought to be normal. Elevated triglycerides commonly occur along with low HDL, but they also act independently. High triglycerides are a common cause of heart disease, even in people with low or normal cholesterol values. It is crucial that you and your doctor not ignore triglycerides, but pay close attention to them if you are to succeed in controlling your risk for heart disease.
National guidelines (ATP-III) recommend keeping triglycerides <150 mg/dl. However, the adverse effects of excessive triglycerides begins as low as 45 mg/dl, and get really bad with triglycerides >100 mg/dl. (In our program for reversal of heart disease in which we aim for zero coronary plaque growth or reduction, we target triglyceride levels of 60 mg/dl or less.)
You may notice that low HDL and increased triglycerides are patterns that are also typically associated with pre-diabetes, also called metabolic syndrome, and diabetes. In our society of packaged, processed carbohydrate-rich foods and sedentary lifestyles, metabolic syndrome and diabetes are running rampant. It means that increased triglycerides and VLDL are also running rampant. The result: a 3 to 7-fold increase in risk for heart attack. Eliminating the metabolic syndrome is another battle to fight to conquer heart disease.
In his next post, Dr. Davis will discuss ways of lowering triglycerides.