Cholesterol Series Part 2: What is It & Why?

Welcome to Part 2 of our journey through dietary cholesterol lore, into what actually works best for our long-term health.

Last week in Part 1, we discussed some historically significant incidents that ultimately led to blood cholesterol levels becoming the most popular measure of health, which then led to the vilification of cholesterol in the food that we eat, and by extension, all the fat that we eat.

This week, we’re focusing on what cholesterol actually is and what it does in our body. Then next week, we’ll talk about a more accurate and appropriate measure of long-term heart health, C-reactive protein.

What is cholesterol in your diet?

Cholesterol is a type of fat. It is the type of fat the makes up the walls of animal cells. Cholesterol is the building material for every cell in every animal. That’s why animal foods have cholesterol in them. It’s not coming from the saturated fat, it’s not even entirely coming from the animal’s fat. The structure of cholesterol is different than what we normally think of as “fat” in our food. Cholesterol is a completely different kind of fat from the fatty acids inside fat cells.

Animal products are the only place we encounter cholesterol in our diet, and it doesn’t matter if it’s “lean” or “low fat”. Every cell of every animal is made out of cholesterol. Plants, on the other hand, do not produce or contain any cholesterol. According to a survey conducted by the CDC, the average American man eats about 307 mg of cholesterol each day. Vegetarians will obviously consume less, and vegans, none at all.

What is cholesterol in your body?

In human bodies, cholesterol is also the structure of every cell. We are part of the animal kingdom, after all. In addition to making up the structure of every cell in our bodies, cholesterol is used to run many other processes in the body. Cell walls: made of cholesterol. Processes inside cells: powered by cholesterol. Hormones: made of cholesterol. Brain: 70% cholesterol. Neuron firing: can’t happen without cholesterol. Stomach acid: made from cholesterol. Intestinal bile: made from cholesterol. Cholesterol is kind of a big deal.

Cholesterol is so essential to the structure and processes of the human body that every single one of our cells produces its own cholesterol. Our own body makes as much as it needs on demand. We need so much, in fact, that we could never eat enough to power our body.

Maybe that’s why our bodies never even bothered to evolve the ability to digest it. Cholesterol is too important to just leave it up to us to eat enough.

The cholesterol that we eat and the cholesterol in our bodies are not the same.

Sources on the internet often claim that about 80% of the cholesterol in our body is made by our body, mostly by our liver. The problem with this claim is that we cannot digest cholesterol, so there’s no way for any that we eat to end up in our bloodstream. 100% of the cholesterol in our body is made by our body.

The cholesterol that you eat makes no difference to the amount that’s in your body because human bodies cannot digest cholesterol. Our digestive tracts are only equipped to digest and absorb glucose, amino acids, and fatty acids. Cholesterol is a fat molecule, but it’s not a fatty acid. It’s a sterol, which is not something we digest.

When we eat cholesterol, there are two options as shown in this graphic from an eCampus Ontario nutrition textbook. It either gets absorbed into our liver and used to make bile, which then aids in digestion of the other things we’ve eaten at that same time, or if we’ve eaten it with soluble fiber, it may bind to the fiber and pass out of our body, not being used at all. That’s it. Those are the two ways our body deals with any cholesterol we eat. The cholesterol we eat does not end up in our bloodstream. Ever.

Even if it did, which it doesn’t, we couldn’t eat enough (or enough less) to make any meaningful change in the amount inside our body.

A healthy total cholesterol level is considered to be under 200 mg/dL. The average human has about 5 liters of blood in their body, which is 50 dL. So 200 mg/dL of cholesterol means that in your entire bloodstream, there are about 10,000 mg of cholesterol flowing.

Recall that the average American meat-eating man eats around 300 mg per day. Those of us who aren’t men, or don’t eat as many animal products, will be eating far less. Now you can begin to see how dietary cholesterol could never be the cause of high cholesterol in the body. You literally could not eat enough cholesterol to amount to even 1/10th of how much is in your body. And then you have the fact that vegans have the same amount of cholesterol in their body, despite never eating any.

Your body synthesizes as much cholesterol as it needs. You do not need to eat it, what you eat won’t digest anyway. And if you never eat any, that doesn’t matter either. The cholesterol level in your blood has absolutely nothing to do with how much you ate. It has everything to do with how much your body needs, and it all comes from inside.

In spite of these biological facts, we are told that when we have lots of cholesterol in our blood, it’s a bad thing. If you’re annoying like me and keep asking why, then you get told that a high level of cholesterol in your blood leads to heart disease. You ask why again and you’re told that all that cholesterol in your blood will form deposits along the walls of your blood vessels, leading to cardiovascular disease.

We are supposed to believe that this absolutely essential building block of all cells and processes in our body, that our body always produces in the amounts that we need, is bad while it’s in our bloodstream. We’re supposed to eat less of it and take medication to lower it. Now that we understand what we eat has zero impact on how much cholesterol we have inside our body, this prescriptive tradition is not only outdated and wrong, but frankly, dangerous.

We cannot regulate our cholesterol. Our body does it automatically. Do you really believe that your body is stupid and just one day decided to overproduce this cholesterol stuff that’s used in every cell, but is somehow bad for us while it’s being transported around our body? Of course not. Our bodies are smart.

What is the cholesterol in our blood?

Is there perhaps something different about cholesterol while it’s in our bloodstream? Well, sort of.

Here’s the thing about cholesterol, and all fats: They tend to stick together in big blobs. If we had big blobs of fat coagulating in our blood vessels, that really would be an urgent problem. Our bodies are smart, though. Our bodies prevent fat blobs from happening by transporting fatty acids and cholesterol around in our bloodstream in little protein carrier pods called lipoproteins. Fats rides around in our bloodstream encased in these protein carriers, and are delivered wherever they’re needed, anywhere and everywhere. The bloodstream is like the highway of our body. It is how all of our nutrients travel to where they are needed. The only difference is fat molecules are chauffeured around in protein carrier pods like the nutrient royalty they are, while all the other nutrients drive themselves.

When we have a blood test to determine our blood cholesterol level, it’s not actually cholesterol that is being measured, it’s the carrier pods. Cholesterol is only present in the blood inside of those pods. You’ve probably heard that blood cholesterol comes in two forms, HDL, the “good”, and LDL, the “bad”. That’s not quite accurate. More HDL is correlated with positive health outcomes, while high levels of LDL is somewhat correlated with negative health outcomes, but as we saw last week, certainly not always. They call one bad and one good because of these correlations, but correlation doesn’t mean causation. HDL and LDL are not even cholesterol, they are just the protein carriers that can carry cholesterol.

Let’s look deeper into these carriers. Every internet source will tell you that LDL is the bad cholesterol because it’s bringing cholesterol to cells, and it can build up in your blood vessels and forms plaques. Every source will also tell you that HDL is the good cholesterol because it removes the cholesterol built up in your blood vessel walls and transports it back to your liver to be removed from the body. There’s just one problem with these descriptions. They’re not proven facts. They’re a working hypothesis, and they’re almost certainly wrong. I know I’m beginning to sound like a broken record, but hang on to your hats, we’re just getting to the good part.

LDL and HDL are the same structures. The only difference is how much fat they happen to be transporting. Here’s a diagram of HDL, LDL, and a few other lipoproteins from the same textbook referenced earlier.

They are all the same.

What the lipoprotein is called LDL, HDL, or chylomicron (these carry triglycerides), simply comes down to how full they are at any given moment. They change size like little balloons as they pick up or drop off the fat. When one is mostly full, it’s considered to be LDL, Low Density Lipoprotein. When a carrier is less than half full, it’s considered HDL, High Density Lipoprotein. The average HDL is less than 25% full. HDL is the allegedly good kind of cholesterol that is said to be removing cholesterol from our body to regulate the amount in our blood.

I say “allegedly” because it is not an established fact that HDL removes cholesterol from your body, despite what WebMD might say. This paper published in the Handbook of Experimental Pharmacology, says “HDL has been proposed to promote macrophage reverse cholesterol transport…” That’s right. The idea that HDL transports cholesterol out of your body is simply a proposal, not a fact accepted by all researchers. It’s a guess, and there’s strong evidence to suggest that it’s a wrong guess.

Researchers have been disappointed and confused by the fact that when they increase HDL in people, they don’t get healthier. HDL is supposed to be the healthy cholesterol, after all. That same pharmacology paper goes on to say that lower levels of HDL are associated with increased risk of cardiovascular disease, but “recent clinical trials on lipid-modifying drugs that increase plasma levels of HDL-C have not shown significant clinical benefit.”

On the other end of the confused research spectrum, we have this study. Mice were engineered to lack a certain gene that supposedly resulted in them having no HDL. Literally nothing about their overall cholesterol levels changed. “We conclude that plasma HDL levels… do not control net cholesterol transport… indicating that the importance of HDL in reverse cholesterol transport requires re-evaluation.”

So what we’ve learned here is that adding more HDL does not improve cholesterol levels or health. Likewise, removing HDL does not worsen cholesterol levels or health. But HDL is associated with improved health. It’s supposed to be the good cholesterol! What the actual heck is going on?

Let’s logic our way through this situation.

LDL and HDL are the same structure. They are proteins that carry fats around in our bloodstream. The only difference between them is that one is full and one is empty. If HDL’s purpose is to remove built up cholesterol from our blood, it does a very bad job, considering that most of them are empty. Good thing that’s not what they’re actually for.

Whenever any of these carrier pods are full of fat, they are called LDL. LDL are full of fat. That doesn’t mean they are full of cholesterol. All fats need to be carried by lipoproteins when they’re in the bloodstream. LDL could be full of fatty acids to deposit into fat cells, or they could be full of cholesterol to use as part of the immune system’s healing process. Remember, cholesterol is the building material of cells. Anytime there is damage to cells, cholesterol is needed to repair it and there should be lots of LDL scurrying around to get cholesterol to the site of the damage to help it heal.

When LDL delivers fatty acids to a fat cell, it just empties the fat out into the fat cell, which means the LDL has now become an HDL because it’s now empty. The HDL then travels back to the liver to pick up some more fat and become an LDL again.

However, when LDL delivers cholesterol as part of the healing process, the entire particle, the cholesterol and the protein carrier, is absorbed into the cell that’s being healed. That LDL does not become an HDL, it becomes part of the healing cell. This, my friends, is the answer to why LDL are present in the plaques in your arteries, and also why HDL are correlated with better health, yet changing the amount of them doesn’t change health in any way. LDL are carrying cholesterol to rebuild damaged cells in our body. HDL are empty. They have nothing in them. These carriers are only considered HDL when they are done doing something and currently doing nothing! Adding or removing nothing isn’t very likely to change anyone’s health, is it?

Ultimately, having a relatively high percentage of lipoproteins as HDL does mean that you are healthier, but not in the way we’ve been taught to think. More HDL means that there are fewer immune processes going on in your body. More of your carrier pods are doing processes like dropping fatty acids off to cells for energy or storage, and less of them are carrying cholesterol to repair damaged cells. That translates to proof that you’re in a good health state, but the HDL itself did not make you healthier. You have more HDL because you are healthier.

So can you change your blood cholesterol levels with diet?

Yes you can, but before we go into how, please repeat after me. Cholesterol. Is. Good. Cholesterol is never bad. It is always good. You cannot have too much cholesterol in your body. You have as much as you need. How much you eat, or don’t eat, has no impact whatsoever on the levels in your blood. All of the cholesterol in your body is produced by your body. It’s so important that every single cell in your body can and does produce cholesterol when it needs to.

If you’re currently screaming at your screen, “why do plaques form if the LDL absorption and immune system process is normal and healthy?”, that’s a very good question! That is a topic that will take an entire post. This one is already long enough, but keep an eye out for that one. It’s coming. This post is just explaining why there is cholesterol in your body and why that is always good thing for you. Far from the gluttony-imposed coagulation fairy tale we’ve been fed all our lives, high blood cholesterol levels are produced by our body as a part of the immune system’s healing process. That’s a healthy process. It does indicate that there’s some damage being done that needs healed, but the cholesterol itself is not the problem. It’s part of the solution. How arterial plaques form is a topic for another day.

In the meantime, the way to improve your cholesterol levels and lower your risk of plaque buildup with your diet is not by eating less cholesterol. The way to improve your cholesterol levels with your diet is to eat foods that digest easily and don’t contain anything that contributes to systemic inflammation. It’s systemic inflammation, damage that requires cholesterol to heal, that increases our LDL levels and can lead to buildup in our blood vessels. Lower the work your immune system is doing and you will lower your LDL cholesterol levels, because your body produces that cholesterol as part of the healing process.

Next week, we’ll pick up the inflammation thread here and discuss the test that measures the amount of systemic inflammation we have, CRP. CRP is recognized as a much better predictor of future cardiovascular disease than cholesterol, and it’s much less convoluted, I promise!

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