Why Your Good Cholesterol May Now Be Bad: A HealthCentral Explainer

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  • I’ve finally started to understand my yearly cholesterol results, and now science throws another wrench into decoding lab work. Go figure. Researchers at the Harvard School of Public Health (HSPH) have found that when the surface of high-density lipoprotein (HDL) cholesterol bears a small protein called apolipoprotein C-III (apoC-III), it actually increases the risk of heart disease. When there’s no sign of this protein, however, the researchers say HDL cholesterol is especially effective at protecting the heart.


    What exactly is HDL cholesterol?

    HDL stands for high-density lipoprotein, but it’s more commonly known as "good" cholesterol. Lipoproteins are made of fat and protein and they carry cholesterol, triglycerides, and other fats, called lipids, in the blood from other parts of your body to your liver. HDL is kind of like a watchdog inside your arteries, constantly removing cholesterol from areas where it shouldn’t be, such as artery walls and tissues. By also acting as an anti-inflammatory agent, HDL also keeps your arteries from getting too narrow. Because it’s so good for your body, you’ll want to keep this number high (above 60 mg/dl)

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    [SLIDESHOW: Eight Foods That Lower Cholesterol]

    What’s apoC-III and why is it getting in the way of my HDL?

    ApoC-III is a pro-inflammatory protein that resides on the surface of some lipoproteins, including HDL and LDL (low-density lipoprotein, or "bad") cholesterol. Unfortunately, it looks like this protein can inhibit HDL from doing its job. By examining blood samples from 18,225 men and 32,826 women, the Harvard researchers found that the HDL without the apoC-III protein maintained its heart-protective qualities. However, the 13 percent of HDL cholesterol that had apoC-III present on its surface was associated with a higher risk of coronary artery disease. The men and women in the study who had HDL apoC-III showed a 60 percent increased risk of coronary artery disease.


    How do I know if I have apolipoprotein C-III (apoC-III)?

    On a normal cholesterol lab test, you most likely won’t know. If you’re concerned, speak to  your doctor and see if instead of just getting your HDL levels measured, the lab can also test HDL with and without apoC-III.


    How can I lower my risk for heart disease?

    There are many things you can do to lower your risk for heart disease. First off, if you’re a smoker, get yourself on a path to quit. Inhaling cigarette smoke produces several effects that damage the cerebrovascular system, putting smokers (and those on receiving end of second-hand smoke), at risk for stroke. You can also change your diet and integrate exercise into your daily routine.


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    The bottom line

    It’s important to remember that only a small percentage of those tested in the study had the apoC-III present on their HDL. So you should continue to strive for higher HDL numbers--don’t forget all the good they do for your arteries. One of the biggest threats to HDL is trans-fats. That means you should try to stay away from the donuts, cookies, French fries, and anything else that’s overly processed. Stick to healthy fats and foods with high doses of omega-3. If you’re overly concerned about the possibility of apoC-III in your blood, speak with your doctor and see if he/she feels a blood test is warranted.


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    Paddock, Catharine.  (20 May 2012).  Some “Good” Cholesterol May Be Bad For Heart.  Medical News Today.  Retrieved from http://www.medicalnewstoday.com/articles/245611.php

Published On: May 29, 2012