Your Questions About Cholesterol Answered

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Ashish Sarraju, MD:

Hi everyone. My name is Ashish Sarraju. I'm a staff cardiologist here at the Cleveland Clinic main campus in Cleveland, Ohio. I'm part of the Section of Preventive Cardiology and Rehabilitation, and my specialty is in managing risk factors for heart disease, mainly high cholesterol. So today we're going to spend a few minutes talking about high cholesterol and high lipids, and what I'm going to do is break it down by some common questions we often get from our patients to hopefully digest this information into easy little sound bites.

So one of the most common questions and maybe one of the most fundamental questions is what is cholesterol or what are lipids? And that's such an important concept to understand when talking about risk factors. But what I tell patients is saying lipid is almost like saying protein or something exceptionally broad. Lipids are particles that are present throughout our body and serve a number of different functions. They're part of membranes, they're part of signaling pathways. They do a number of different things. Within the lipid family, you have cholesterol, again, a specific type of particle. Cholesterol also serves many different functions, but when you're talking to a cardiologist and they say high cholesterol, they're usually referring to the results of certain tests that they've ordered or your primary care doctor or other doctors may have ordered.

So when we say high cholesterol, we're usually talking about the results of that specific test. And what are those tests? Well, if you've ever done a cholesterol panel, you know that there are different results that come up. There's the total cholesterol. There's something called LDL or low-density lipoprotein cholesterol, HDL or high-density lipoprotein cholesterol, triglycerides, and several other results. And when we talk about cholesterol, what we do is look through these tests and interpret them in terms of risk for heart disease, specifically within that test.

If someone has heart disease, perhaps the two most important labs that we look at are the LDL cholesterol and the non-HDL cholesterol. And when you look at the regular lipid panel, you'll see those numbers and you'll see a range for what is normal. But what is normal is usually decided by a conversation between a patient and their physician, depending on their overall health and their risk.

In addition to the LDL cholesterol and the non-HDL cholesterol, triglycerides can also be an important marker for health. Triglycerides can be high if someone's diabetes is not controlled, if someone's diet is not controlled, if there's more alcohol use than is recommended, if weight could be better. So high triglyceride levels often are markers of other conditions or lifestyle conditions and can serve as a motivation to improve those factors, which also can help reduce heart disease.

But when we talk about cholesterol-lowering medications, predominantly what these medications do is try to lower LDL cholesterol, and by doing that, they lower non-HDL cholesterol. Now, without going into the science of it too much, the reason we do this is because we believe that there's a particle called Apo B, Apolipoprotein B-100, which is part of this LDL cholesterol particle. And we believe that Apo B, Apolipoprotein B-100, is really the predominant cause of heart disease or blockages in addition to, of course, other risk factors that contribute to it as well.

Another question we get is what is hyperlipidemia? What is hypercholesterolemia? Like I briefly mentioned, quite simply it's having those levels higher than is recommended for you in your own individualized scenario based on your risk factors and the conditions you may have. If it's higher than we would like, we call it hyperlipidemia or hypercholesterolemia. But within that family there is a condition called familial hypercholesterolemia, which is another question we get. What is familial hypercholesterolemia or FH? FH is a specific condition of high cholesterol where folks have a very high LDL cholesterol, often called the bad cholesterol, although I think that's a little simplistic. They have very high LDL cholesterol elevated in a lifelong manner because of genetic mutations that expose their arteries to high LDL cholesterol for years and years.

Generally speaking, FH comes in two forms where if you have one copy of the mutation or if both the genes that you carry have the mutation, that's called heterozygous FH and homozygous FH. Heterozygous FH, where folks have one copy of the mutation is much more common than homozygous FH. Heterozygous FH, some people say it may be present in one in 250 people in the United States, and that only 10 to 30% are actually diagnosed with it, which is remarkable considering that that's a condition that is present in an entire family, not just in a single individual. So when we say FH, we're usually referring to that specific condition. Folks may also have very high LDL cholesterol levels that are genetic, not because of a single mutation, but because of hundreds of thousands of mutations. That's called polygenic FH. So as you can see, there are all these different conditions that we can think about, that a specialist can think about if there's concern about FH.

Now, one very common question is whether a lipid panel, a cholesterol test should be fasting or non-fasting. Very common. Traditionally, as I'm sure everyone knows, we have done fasting lipid panels where you would fast for 12 hours or so, go in and get the results. However, pretty good research has shown that non-fasting lipid panels are fairly equivalent to fasting lipid panels. The LDL cholesterol, for example, from a non-fasting panel has very comparable predictive value as the LDL cholesterol from a fasting lipid panel. Now, there are minor differences. The triglycerides may be slightly higher or much higher in a non-fasting blood test. But for the sake of convenience, for logistics and because the differences are generally minor in most people, I tell my patients it's perfectly fine to start with a non-fasting lipid panel anytime of the day. And in some cases, that may be even more convenient or safer. For example, if you have diabetes and you're on insulin, you don't have to strategize around the fasting lipid panel.

Finally, one question about cholesterol medications that often comes up. The most common cholesterol medications that we use are called statins, and folks may ask when they should take their statin. You may have heard folks telling you to take your statin at night. Now, let me comment on that for a second. So cholesterol biosynthesis, which is the synthesis of cholesterol where our body makes it, we think that peaks at night, which is why the original recommendation for the statins was to take them at night. And this was for the shorter-acting statins, which would act just for a few hours. So you would really want to overlap the effect of the statin with when we think the cholesterol is being produced so that you get a really good therapeutic effect. But for the newer, longer-acting statins, they have long lives. And for the newer ones, it almost doesn't matter like rosuvastatin or atorvastatin, which are longer-acting than older ones like simvastatin, which is shorter acting. So if you're on these longer acting statins, you should be okay taking it any time of the day, but as long as you take it consistently. And that's what I tell patients, the best time of the day to take it is the time where you are going to take it every day. But if you're on a shorter acting statin like simvastatin, it may be better to take that at night.

Thank you everyone for listening to us and have a good day.

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