What is cholesterol and why are high levels a problem? Here’s what you need to know about this highly-nuanced topic.
What is Cholesterol?
Cholesterol is a fat-like molecule that is essential for human life. It is required by the human body in several ways:
- As an important component of cell membranes
- For the synthesis of Vitamin D
- For the production of hormones in the body (such as testosterone and estrogen/progesterone)
- As a component of bile salts, which are required for the digestion of fats and absorption of fat-soluble vitamins A, D, E & K.
Given that cholesterol does not dissolve well in blood (due to its high water-content), it must be shuttled throughout the bloodstream via lipoproteins. Blood tests highlight the number and type of lipoproteins in the body, which is where we get the classifications of “good” High Density Lipoproteins (HDL) cholesterol and “bad” Low Density Lipoproteins (LDL) cholesterol. There are other lipoproteins as well: Intermediate-density Lipoproteins (IDL), Very Low Density Lipoproteins (VLDL), and chylomicrons.
While us humans like to label things as “good” or “bad”, this is an oversimplification regarding cholesterol. Our “bad” LDL particles are plentiful and have a distinct purpose: They contain at least two-thirds of all circulating cholesterol and are responsible for transporting cholesterol from the liver to peripheral tissues (which again, need cholesterol in order to function properly). HDL particles are responsible for the opposite: They transport cholesterol from the peripheral tissues to the liver, which is why this cholesterol is protective of health, as it can “clear” excess cholesterol from the body.
The main lesson here is that when it comes to human health, there is a sweet spot for everything. When the body is oversaturated with cholesterol, there will be more lipoproteins for transportation, and this increased activity is more likely to cause inflammation to blood vessels. Think of this as though there are an excessive number of cars on a highway leading to faster wear and tear on the roads and to an increased likelihood of car accidents. On the flip side, too little cholesterol and the body becomes deprived of the precursors required for optimal cell membrane integrity, hormonal production and fat digestion/absorption.
To make a long story short, just remember that all cholesterol serves a purpose. If blood cholesterol levels become out of whack, cholesterol itself is not to blame: Something else is driving this outcome, and resolving this root cause is the key to improving health.
Did you know? If tests reveal that you have plaque in your arteries, do not panic. Plaque formation starts *for everyone* in childhood. Being alive causes plaque formation, particularly at “bends” in your arteries known as bifurcations. What you need to know is how much plaque there is and if you’re actually at an elevated risk relative to what would be considered a normal/healthy amount of plaque for your age.
Dietary cholesterol vs. Blood cholesterol
Blood cholesterol levels can rise in two ways:
- Through the food we eat (via digestion of dietary fat)
- Through making our own (cellular synthesis, which mostly takes place in the liver)
Please note that it does not rise in accordance with the consumption of cholesterol-containing foods (believe it or not, eggs are not the enemy). This is why there are no longer dietary cholesterol recommendations: The human body is equipped to make more cholesterol if necessary, or to shut down natural production and/or decrease absorption if enough is consumed via dietary fat.
This also explains why there is a recommended daily limit for saturated fat intake: When excess saturated fat is consumed in the diet, this can drive up blood cholesterol levels. You’ll notice that the word “can” is italicized, and this is because it doesn’t happen in all cases. While there is a correlation here, there are other protective factors when it comes to saturated fat intake and we’ll get to those shortly.
Why is high cholesterol bad for us?
High cholesterol, or hypercholesterolemia, is a risk factor for atherosclerosis (the thickening of blood vessel walls), which is a cause of cardiovascular disease (CVD). There is a wealth of research associating high blood cholesterol levels to an increased risk of heart disease and overall mortality (aka, to dying at a younger age). This is partly why, for a long time, people were told to stop eating cholesterol-containing foods because we did not yet know the mechanisms that drove up HDL or LDL and vice versa.
Causes of high cholesterol
As a general rule, disease is caused by excess and chronic inflammation in the body. Inflammation is a natural process that is brought on for a number of reasons and is required for leading a long and healthy life; if you get injured, short term inflammation is needed to help the healing process. However, when inflammation becomes chronic (for any reason), health declines. High cholesterol levels are no exception: Research demonstrates that LDL particles will only be actively transported into artery walls when inflammatory signalling molecules are present. With this in mind, the main risk factors that will drive high cholesterol and cause heart disease are:
- Physical inactivity
- Chronic stress
- Habitual alcohol intake
- Excessive sugar intake, which leads to chronically high glucose/blood sugar levels (which drives up LDL production in the liver)
- Excessive saturated fat intake
The common thread among the top 6 causes here is that these are all highly inflammatory inputs to the human body. If you are exposed to one or more of these stimuli for an extended period of time, blood cholesterol levels will rise.
This brings us back to the saturated fat conundrum because while it does contribute to elevated blood cholesterol levels, it does so from a place of “normal” cellular signalling, rather than as a result of inflammation. Decreasing dietary saturated fat intake can indeed lead to lower blood cholesterol levels but the jury is still out on whether or not saturated fat drives impaired health as far as root causes go.
Additionally, cholesterol levels have a genetic component so if a family member has high cholesterol, it is possible that this trait can be passed onto the next generation. That being said, genetics alone do not guarantee that someone will have high cholesterol and cannot be solely to ‘blame’ even if someone does. Even with a genetic predisposition, environmental factors such as the 6 listed above will still need to be present in order for cholesterol levels to rise to harmful levels. In short, lifestyle choices matter.
Can high cholesterol be beneficial?
While there isn’t data to indicate that high cholesterol is desirable, recent research has demonstrated that there may be some circumstances in which high cholesterol may not be a problem.
A new genetic phenotype has recently emerged in the literature: Lean-mass hyper-responders (LMHR). This is a population of otherwise healthy individuals whose only outlier in blood markers is high LDL. People in this population have a low body fat percentage, a normal BMI, healthy levels of HDL and healthy levels of circulating triglycerides (TGs). LMHRs are a segment of the population who consume a low-carbohydrate/high fat diet, and this dietary pattern correlates to the elevated LDL blood marker. Specifically, research has always demonstrated a link between high dietary SFA intake and high LDL but the LMHRs demonstrate that this doesn’t inherently mean it’s dangerous on its own.
There is much research to be done, but for now this appears to be an example of where high cholesterol in isolation does not appear to be a risk factor for CVD or premature death– and why we should always be looking beyond blood markers to target the underlying cause of pathology, rather than specifically trying to change a singular symptom (aka to “just” lower blood cholesterol).
Treating the cause vs. treating the symptom
If you’ve made it this far, you understand that a high blood cholesterol reading is a sign that there’s excessive inflammation in the body, rather than the cholesterol itself being the issue. Research demonstrates that inflammatory markers in the body (levels of c-reactive protein or CRP, which rise along with inflammation in the body) are better indicators of cardiovascular events and death than markers of high LDL.
Slowing and regressing the buildup of plaque in artery walls is therefore seemingly dependant on at least the following two factors:
- Reducing blood cholesterol
- Reducing/eliminating the inflammatory processes that are driving atherosclerosis
While there are drugs (known as statins) to address the first point by targeting/reducing levels of cholesterol directly, these drugs don’t address point two which is the root cause of the problem. If you discover you have high blood cholesterol, you can take control by focusing on different lifestyle interventions. Every situation is unique, so it is up to the individual to determine where they have the biggest opportunity for improvements in overall health and then start there. Here is a list of impactful lifestyle interventions that can lead to lower cholesterol and, more importantly, improved health and well being:
- Smoking Cessation
- Improving sleep consistency and quality
- Reducing alcohol intake
- Increasing physical activity & exercise
- This is the quickest way to stabilize plaque formation in arteries, as the effects of exercise immediately change blood vessel function and reduce CVD risk
- Increasing food-based dietary fiber intake (think: vegetables & root vegetables)
- Decreasing ultra-processed food intake (notably decreasing intake of trans fats and processed sugars)
- Decreasing saturated fat intake (which will happen by limiting ultra-processed foods)
You might notice that the common thread amongst these behaviours is that they’re all generally recognized as being “healthy” habits. While the answer here may seem simple, creating change in today’s world isn’t often easy. If your cholesterol levels are high, pick one area of this list that seems the most attainable to you and you’ll be on your way to reducing your risk factors for CVD and beyond. Once you feel you have a handle on one element, add in another layer.
The Lipid Hypothesis and Statin Drugs
The Lipid Hypothesis states that high cholesterol (namely LDL) leads to CVD. In the 1980s, cholesterol-lowering drugs called statins hit the market and have been the main pharmacological strategy for heart disease prevention ever since.
While it is generally accepted that the most effective strategy for lowering blood cholesterol levels is via the combination of statin therapy and lifestyle intervention, this does not mean that this is the best strategy for improving overall health or reducing risk of death from all causes.
Statin drugs for lowering cholesterol can be seen akin to liposuction for reducing obesity: The tool will address the surface symptom, but it will not resolve the underlying cause. Statins do not eradicate cholesterol. Instead, they lower blood cholesterol by sequestering this cholesterol within cells. Does this actually lead to better health outcomes? The jury is still out, and given that rates of CVD have doubled since statins were introduced, there’s reason to assume we might be missing the forest for the trees. Furthermore, there are often unsavory side effects and correlations linked to statin use which include but are not limited to:
- Mitochondrial dysfunction and decreased energy
- Muscle soreness/discomfort
- These top two are especially problematic because these symptoms might get in the way of someone exercising, which is one of the best known ways of managing inflammation.
- Links to both the onset and escalation to other disease such as cancer and Type-II diabetes
There is also research showing that statins aren’t as impactful as was once thought; studies have shown that statin treatment may only extend life by a few days on average. In fact, the early reputation of statin drugs as a breakthrough treatment was based on relative risk, which is a misleading way to report findings of research trials. As mentioned above, when absolute risk is assessed, the benefits of statins regarding longevity and protection against heart disease are minimal at best.
If there is doubt around the efficacy of statins to reduce CVD, and if they don’t address the root health problems that lead to high cholesterol in the first place, why do doctors prescribe them with such frequency? Part of the answer is liability: A doctor *must* present patients with all options for lowering risk of premature death, particularly if the patient is not interested in or able to make any lifestyle modifications. The Lipid Hypothesis is the basis of current recommendations, and research shows that statin drugs lower cholesterol and that high blood cholesterol is associated with CVD. Doctors should always give patients the opportunity to take a therapeutic lifestyle modification route but if a patient is not willing or able to do so, then statins have to be prescribed. Doctors are in a position where they are trying to help patients minimize the risk of disease and death and sometimes this means needing to rely on pharmaceuticals when other options are refused.
As with everything in life however, it is always a personal choice when deciding whether or not to use prescribed medication. This article is not making a recommendation one way or another and its intention is to explain why statins are prescribed for high cholesterol, and why they can be viewed as an overall positive or negative for health given the individual situation and desired outcome.
Many individuals do not fully understand what cholesterol is and usually hear about it in the context of “good” or “bad” levels and assume that drugs will be necessary if a family member has had to go that route. Even more importantly, many are unaware of which behaviours are most impactful for managing cholesterol levels favourably for long term health. Knowing more about bodily processes and functions can reduce fear and empower individuals to make informed choices prior to any diagnosis; We hope this article can help.
- Cholesterol is a fat-like molecule that is essential for human life.
- Plaque formation starts in teenage years for everyone and exists in all bodies. Presence of plaque in arteries is not an emergency if levels are appropriate.
- The consumption of high-cholesterol foods does not directly lead to an increase in blood cholesterol.
- Genetics do not predict your cholesterol levels or dictate an inevitable need for pharmaceutical drugs.
- High cholesterol levels are driven by chronic inflammation, caused by behaviours such as smoking, physical inactivity, chronic stress & habitual alcohol intake.
- New research shows that some people can have high cholesterol levels and still be at a decreased risk of CVD. This is by and large a physically active population.
- Statin drugs decrease cholesterol levels but don’t address the root causes of inflammation that are driving disease.
- If a patient will not make the appropriate lifestyle and behaviour changes, doctors must prescribe statin drugs to slow or reduce the risk of complications for the patient.
- Lifestyle modifications will lead to lower cholesterol levels and ultimately address the root cause of disease.
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