According to the Centers for Disease Control and Prevention (CDC), heart disease is the leading cause of death in the United States—more than even all types of cancer combined. One of the simplest indicators of a person’s heart health is their cholesterol levels. But what exactly is cholesterol, and what kind of tests are available? Dr. Robert Segal, a board-certified cardiologist and founder of Manhattan Cardiology, has answers to those questions and more.

First and most importantly, what exactly is cholesterol?

“Cholesterol is a natural, waxy substance made by the liver that’s found in most tissues of the body. It has a lot of important uses from digestion to hormone production,” says Segal.

The liver produces enough cholesterol for all of the body’s functional needs, but cholesterol can also be found in many foods. In effect, this dietary cholesterol can lead to having too much cholesterol overall in the body—and in particular in the bloodstream—where it starts to stick together and build up.

“Because of cholesterol’s waxiness, it can stick to the inner walls of arteries. Once that starts, more and more cholesterol tends to build up, narrowing and hardening the arteries. This increases blood pressure, decreases the supply of oxygen to the heart, and can directly cause a heart attack,” says Segal.

There are a few different types of cholesterol that are important to know about.

Low-density lipoprotein (LDL). This is often referred to as “bad” cholesterol or “L” for “lousy”, although the body does need a small amount of LDL cholesterol for normal functioning. Lower LDL levels are associated with lower risk of heart disease and stroke.

High-density lipoprotein (HDL). This is often referred to as “good” cholesterol. HDL cholesterol can collect extra LDL cholesterol and return it to the liver to be broken down and removed from the body. Higher HDL levels are associated with lower risk of heart disease and stroke.

Triglycerides. This is a type of fatty compound the body uses to store extra energy. Triglycerides can be broken down later to release energy, but if the need never arises, the fat continues to build up. Lower levels of triglycerides are generally healthier.

“Often times when someone’s cholesterol levels are too high, there aren’t any noticeable symptoms until they have a heart attack or a stroke. But if someone knows they have high cholesterol, there’s a lot that can be done to lower their risk of those dramatic outcomes. That’s why it’s so important for people to regularly have their cholesterol levels tested. This is generally a simple procedure that can be performed during an annual physical,” says Segal.

There are several types of cholesterol tests available. Some are more generalized, while others have more specific uses.

• Lipid Panel. This very common test can be performed in a doctor’s office and yields results in a couple of days. Blood is drawn and sent to a laboratory for analysis. This type of test typically directly measures total cholesterol, HDL, and triglycerides, and then uses this information to calculate LDL levels.

• HDL-C test. This test is usually ordered as needed as a follow up test to a standard lipid panel. It can show whether HDL levels have gone either up or down since a previous screening.

• LDL-C test. Where a standard lipid panel uses a formula to calculate LDL levels, this test directly measures LDL cholesterol. For people with very high triglyceride levels, this may provide a more accurate assessment of LDL levels.

• Lipoprotein (a) = LpA  The amount of lipoprotein in your blood is determined by a lipoprotein test. You may be at an increased risk for heart disease and stroke if you have a high level of lipoprotein (a). 

• CAC test. A coronary artery calcium score uses a CT scan instead of a blood draw. The scan measures the amount of calcium in the arteries around the heart to determine how much plaque is built up. This type of test can help doctors decide if someone would benefit from taking statins (a type of medication) to lower their cholesterol. The higher the calcium score, the higher risk of heart disease.

“Cholesterol tests are an efficient and effective way to find out if someone’s cholesterol levels are too high. But that information is only useful if some sort of action is taken,” says Segal.

While statins and other medications are one available option, most of the time the most significant long-term benefits can be gained from making lifestyle changes.

A diet low in trans fat and saturated fats, refined sugars, and red meats can help lower cholesterol. These foods can be replaced with fish, fresh vegetables, nuts, legumes, seeds, and whole grains. Regular moderate exercise, healthy sleep habits, managing stress, maintaining a healthy weight, and quitting tobacco products are also all associated with improved heart health.

“The best part is that these options don’t require special equipment or a prescription. They’re simple concepts that most people understand intuitively. Sometimes it’s just about getting back to basics,” said Segal.

Manhattan Cardiology is the premier facility for preventive cardiology treatment in New York. Our cardiologists practice under the guiding principle that early detection is the best form of prevention.  www.manhattancardiology.com

Skin treatment research, while still in early stages, indicates that cholesterol added as an ingredient in moisturizers could actually help protect skin from UV damage. According to research published in the Journal of Dermatological Science, other lipid—or fatty—ingredients do not confer the same type of protection, making this a potentially very important discovery.

CHOLESTEROL IS NOT ALWAYS A BAD THING

When most people hear “cholesterol” they think “bad.” The reality, however, is far more fascinating and complex. Yes — high cholesterol can be dangerous, but cholesterol itself, however, is a vital substance for every living creature, and is essential to almost every bodily process, from insulating nerve cells in the brain to aiding digestion to providing structure for cell membranes.

WHAT FUELS YOUR SEX DRIVE? CHOLESTEROL…

Yes. It’s true — every sex hormone in our body is made from cholesterol. It is a critical component of testosterone, estrogen, and progesterone, to name a few. Cholesterol is one of the essential building blocks of the body, in fact, without it we would not be able to have children. Studies have shown that having low levels of cholesterol can actually cause infertility. According to Dr. Jorge Chavarro, of the Harvard School of Public Health: “Women wanting to conceive should examine their diet. They should consider changing low-fat dairy foods for high-fat dairy foods, for instance by swapping skimmed milk for whole milk and eating cream, not low-fat yogurt.”

YOUR BODY HAS A BUILT-IN CHOLESTEROL FACTORY. IT’S CALLED YOUR LIVER.

To function properly, the human body requires, yes, you guessed it… cholesterol. Your liver can make all the cholesterol you need, even if you don’t consume any dietary cholesterol. Fascinating, right? Problems begin, however, when you consume too much saturated fat, which in turn spurs your body to product too much LDL – aka “bad” cholesterol – which can then turn into plaque that can line, and eventually clog, your arteries.

PREGNANT WOMEN NATURALLY HAVE HIGH CHOLESTEROL LEVELS.

A woman’s total cholesterol and LDL cholesterol reach high levels during pregnancy. This is an important part of growing a baby; therefore it’s not a concern… unless cholesterol remains high after giving birth. In a comparative study, published in the Journal of Brain Development, of imaging tests done on babies carried to full term and on those born prematurely, the “good” form of cholesterol — HDL or high-density lipoprotein — appears to play a key role in helping babies form healthy brains.

BREAST IS BEST WHEN IT COMES TO HEART HEALTH.

Research shows that breast milk, which is naturally rich in cholesterol, may offer heart health security later in life. Studies have found that breastfed babies may have lower cholesterol levels as adults, reducing the risk of cardiovascular disease.

INFANT FORMULA HAS ADDED CHOLESTEROL.

To better mimic breast milk, baby formula includes a variety of vitamins, minerals, and, importantly, fats, some of which contain cholesterol. However, there are currently no government guidelines for how much should be added, but it’s clear that cholesterol is critical for vital bodily processes.

HAVING VERY LOW TOTAL CHOLESTEROL CAN ACTUALLY INCREASE SOME HEALTH RISKS.

High cholesterol can carry artery-clogging risks, but having very low cholesterol can also pose some significant health risks. While research is ongoing, studies have shown that cholesterol levels below 160mg/dL may increase your risk for depression, anxiety, and certain types of cancer—and in pregnancy, can lead to low birth weight and preterm labor. Because cholesterol is involved in the production of sex hormones, low levels can actually lead to infertility. If you tend to have low cholesterol, be sure to talk to your health care provider about what you should do.

DAILY MINIMUM FOR DIETARY CHOLESTEROL?

Ok, here’s the scoop – you don’t need to consume any cholesterol through the food you eat to maintain your health. Why? Your liver makes enough cholesterol to meet all your body’s needs. Vegans, who eat no animal products — and hence, no cholesterol – do just fine. So how much cholesterol should you aim to consume daily? Aim to keep it under 300 mg if you have normal cholesterol levels, and under 200 mg if you have heart disease or have been diagnosed with high LDL (aka “bad”) cholesterol.

CHOLESTEROL-FREE FOODS CAN ACTUALLY RAISE YOUR CHOLESTEROL

Sounds crazy, right? But doctors cite this as one of the biggest misconceptions they deal with when talking to their patients about cholesterol. So what’s the deal? Many commercially baked goods, along with many fried foods, contain cholesterol-raising trans fats, most often in the form of hydrogenated vegetable oils. Trans fats, along with saturated fats, are the biggest culprits of high cholesterol from food – but are not listed as cholesterol on nutritional labels or food packaging. You have to be a bit of a detective, read ingredient lists and look at nutrition labels closely, before deeming a food purchase a healthy choice.

A release from the association notes that the study was conducted in Alberta, the only province in Canada that authorizes certified pharmacists to prescribe any needed medications for the patients they see. In other provinces, pharmacists can prescribe certain medications in certain circumstances, but in a more limited fashion.

The study provides strong evidence that allowing pharmacists to prescribe drugs and order lab tests — among other steps in patient care — can lead to positive health outcomes, said the study authors. Theirs is the first study to look at effects of pharmacist care that includes prescribing on cholesterol levels. In previous studies, pharmacists have referred patients to other health care providers, mainly physicians, for medication.

High cholesterol levels are a common problem in Canada. The Canadian Health Measures survey, conducted from 2007 to 2009, found that roughly 36% of all Canadians and 43% of those aged 40 to 59 had unhealthy levels of LDL cholesterol, the unwanted or “bad” type of cholesterol that leads to cardiovascular disease such as heart attacks and strokes.

This study, which started in January 2012 and concluded in mid-2014, tackled the problem of high cholesterol using a treatment and monitoring approach, explained authors Dr. Ross Tsuyuki and Dr. Glen Pearson, both pharmacists and professors of medicine at the University of Alberta.

The release quotes Pearson as saying, “The first step is identifying people who have high cholesterol. If you can’t identify them, it doesn’t matter what you try to do. This involves pharmacists being systematic and finding cases.” Ninety-nine patients with high- or moderate-risk cholesterol levels were found and randomly assigned to “usual care” (a test for cholesterol, a pamphlet on cardiovascular disease, and whatever steps the pharmacist and physician would normally take) or to assessment, treatment, and monitoring.

The approach included assessment of the patients’ risk and health goals and beliefs, repeated follow-up and testing for cholesterol over six months, prescription of cholesterol-lowering drugs or changes to existing prescriptions (many patients had high cholesterol levels despite taking medication), and information about what the test results meant and how the patients’ risk was changing. “The whole package is important,” emphasized Pearson. “The patient needs to understand the disease — the rationale for treatment, what the benefits are expected to be. It needs to be put into an appropriate context.”

The lower level of cholesterol achieved in the treatment group would be expected to reduce heart attacks, death due to coronary disease, and the need for bypass surgery or angioplasty by 13%, and to reduce stroke by 11%.

Pharmacist involvement is key to these results, said the authors. As front-line primary care professionals, pharmacists see many patients at risk for cardiovascular disease, and often more frequently than physicians do. “Our study doesn’t say ‘pharmacists are better than physicians.’ It says we have a different and complementary approach,” said Tsuyuki. Pearson believes that pharmacists have a role in preventive health care. “We are reaching people earlier. If we can treat high cholesterol early, we can prevent problems.”

Since high cholesterol is one of the major public health problems in Canada, it makes sense to have pharmacists identifying and treating the problem, said Tsuyuki. At a recent conference, Tsuyuki asked an audience of US and Canadian cardiologists (physicians specializing in heart disease), “If you were truly serious about public health and wanted to reduce heart disease, why would you not be supportive of having thousands of helping hands — additional primary care providers — supporting you and patients?” He said many of the cardiologists were supportive of the role of pharmacists in prevention of heart disease.

A release from U Penn notes that previous research raised the possibility that HDL might not be quite as protective against heart disease as generally believed by cardiologists, especially after several clinical trials of HDL-raising drugs showed little or no effect. “The thinking about HDL has evolved recently to the concept that it may not directly protect against all heart disease,” said senior author Daniel J. Rader, MD, chair of the department of Genetics. “Our results indicate that some causes of raised HDL actually increase risk for heart disease. This is the first demonstration of a genetic mutation that raises HDL but increases risk of heart disease.”

Rader and his colleagues sequenced the lipid-modifying regions of the genomes of 328 people with markedly elevated HDL (along with a control group with lower HDL) to identify genetic causes of high HDL. One of the genes they focused on was SCARB1, which encodes for Scavenger Receptor B1 (SR-B1), the major receptor for HDL on cell surfaces.

In the course of this sequencing, they identified, for the first time, a person without any SCARB1 function, typified by an extremely high HDL-C level of about 150 mg/dL, whereas the normal level is about 50 mg/dL. The subject had two copies of a SCARB1 mutation called P376L, which the team showed caused a breakdown in HDL receptor function.

Among the many approaches they took, the researchers generated induced pluripotent stem cells (iPSCs) from the SCARB1-deficient person, used them to create liver cells, and showed these new cells had profound reduction in their ability to take up HDL. “This mutation prevents the receptor from getting to the cell surface where it needs to be situated in order to bind and take up HDL,” Rader explained. “This disruption in the receptor’s job is due to mistakes in its folding and processing during protein synthesis.”

Going back to the other sequenced genomes, the researchers were then able to show that persons who carry only one copy of the SCARB1 P376L mutation have significantly higher HDL-C levels. From this, Rader and colleagues had a hunch, based on their knowledge of SCARB1 function and previous studies in mice, that having the SCARB1 P376L mutation, despite raising HDL, might paradoxically increase the risk of heart disease.

Working with other researchers around the world, the Penn team was able to show exactly what they had surmised. “This SCARB1 variant, while rare, is just frequent enough that it allowed us to ask the question about its effect on HDL and heart disease in people with only one copy of the mutation,” Rader said.

The Penn team and their colleagues plan to characterize and test other SCARB1 mutations for their relationship to HDL levels and heart disease. Other genes may also have similar effects. “Eventually we may want to perform genetic testing in persons with high HDL to make sure they don’t have mutations–like this one–that raise HDL but don’t protect against, or may even increase, risk for heart disease,” Rader said. Since the P376L mutation in SCARB1 appears to be specific to people of Ashkenazi Jewish descent, testing in this ethnic group might be particularly important.

Rader suggests that a therapeutic approach to increase the expression or activity of SCARB1 could be a new way to reduce the risk of heart disease even though it would reduce HDL blood levels. “The work demonstrates that the protective effects of HDL are more dependent upon how it functions than merely how much of it is present,” Rader concluded. “We still have a lot to learn about the relationship between HDL function and heart disease risk.”

Photo Credit: The lab of Daniel Rader, MD, Perelman School of Medicine, University of Pennsylvania