Understanding the Variables That Predict Heart Disease
It's very possible your MD orders lab work and you have no idea what or why you're having blood drawn. Well, let's clear up the confusion when it comes to your cholesterol labs.
The terms "lipid panel", "lipid profile", and "lipoprotein profile" are used interchangeably to order the same set of labs. To make reading this easier, I'm going to use "lipid profile" from here on out.
"Lipid" is simply a medical term for "fat". A lipid profile measures fatty substances in your blood. Cholesterol is one type of fat.
When you eat food containing cholesterol or when your body produces cholesterol and releases it into your bloodstream, the cholesterol will attach to a protein. This package of cholesterol plus a protein is called a lipoprotein (lipid or fat plus protein). A lipid profile measures lipoprotein levels in your blood.
Lipid profiles include five components:
LDL - "bad" cholesterol
LDL (low-density lipoprotein) cholesterol carries mostly cholesterol, some protein, and minimal triglycerides throughout your circulation. LDL should be less than 130 mg/dL, ideally less than 100 mg/dL.
VLDL - "bad" cholesterol
VLDL (very low-density lipoprotein) cholesterol contains minimal protein and mainly transports triglycerides. VLDL should be less than 40 mg/dL.
Triglycerides are a type of fat in the blood, not a type of cholesterol. Triglycerides are frequently used to estimate VLDL ("bad") cholesterol. Here's the calculation: triglycerides divided by 5 equals VLDL cholesterol. Triglycerides should be less than 200 mg/dL, ideally less than 150 mg/dL.
HDL - "good" cholesterol
HDL (high-density lipoprotein) cholesterol removes cholesterol from your bloodstream and carries it back to the liver. I like to think of HDL as a vacuum cleaner, picking up cholesterol LDL leaves behind in your arteries, the more HDL the better. HDL should be greater than 40 mg/dL, ideally greater than 60 mg/dL.
Cholesterol is essential to bodily functions, such as building cells and producing hormones. However, too much cholesterol will build up on artery walls, form a plaque, and potentially "plug" the artery resulting in a heart attack or stroke. Total cholesterol is calculated from the above components (Total cholesterol = HDL + LDL + VLDL). Total cholesterol should be less than 200 mg/dL.
Do you see how if you only know your total cholesterol, you only have one piece of the lipid profile?
Now, sometimes your results will include ratios or a risk score. Here's an explanation of what those numbers mean.
A risk score is based on you lipid profile results, sex, age, family history, and various other risk factors. If you have a high risk score for heart disease, it's best to speak with your MD to evaluate your risk score.
Cholesterol : HDL Ratio
You want a low ratio of cholesterol to HDL. A ratio lower than 4.5 is good, but 2 or 3 is best. You can calculate your cholesterol to HDL ratio by dividing total cholesterol by HDL. For example, your total cholesterol is 195 and your HDL is 55. 195 divided by 55 equals a ratio of 3.5.
It's actually not your total cholesterol that has the greatest impact on your heart disease risk. The ratio of total cholesterol to HDL is a critical factor. If your total cholesterol is less than 200, but your ratio is 5, you are still at increased risk for developing heart disease.
LDL: HDL Ratio
This ratio compares the amount of bad (LDL) cholesterol to your good (HDL) cholesterol levels. You want a ratio less than 3.5, ideally less than 2.5. To calculate your ratio, divide LDL by HDL. For example, your HDL is 55 and LDL is 100. 100 divided by 55 equals a ratio of 1.8.
Triglyceride : HDL Ratio
A low ratio of triglycerides to HDL is best, ideally less than 2. To calculate your triglyceride to HDL ratio, divide your triglycerides by your HDL. For example, your triglyceride level is 200 and your HDL is 55. 200 divided by 55 equals a ratio of 3.6.
Lipid profiles are commonly ordered to assess your heart disease risk. Your doctor or dietitian will use the results to determine the best treatment to reduce your risk.
A lipid profile is beneficial, because you know your "good" cholesterol level and "bad" cholesterol levels. The interventions that work best to raise HDL and lower LDL differ, so knowing all your numbers helps you make the most effective changes.
You're probably wondering why a lipid profile isn't always ordered versus simply checking your total cholesterol (and possibly HDL). Cost and time always play a part and if your risk for heart disease is low, then a quick and less expensive screening makes sense. If you are at increased risk, a more complete assessment (lipid profile) may be more appropriate. Everyone's situation is unique, so it's best to discuss what's right for you with your MD.
Be sure to sign up for the free e-course How to Lower Cholesterol in 8 Simple Steps by dietitian Lisa Nelson.