If we’re already talking about building blocks for cell membranes, signaling, and transport then we can’t skip a molecule that spent decades with a bad reputation and is only slowly making a comeback as the biological all-rounder it is: cholesterol.
It’s not a fat in the classic sense, but a so-called sterol; chemically related, but structurally and functionally distinct. And although it’s often cast as a scapegoat, cholesterol plays so many essential roles in the body that you have to wonder how it ended up with such a bad image in the first place. Time to take a closer look.
Few substances have a worse reputation – and few are so misunderstood. Cholesterol is not a neurotoxin. It’s a vital building block, signaling molecule, and protective factor. We can’t live without it – and the body knows it: it produces cholesterol on its own, every single day, and in surprisingly large amounts.
This article is Part 2 of my Fat Guide series.
In Part 1: Understanding Fat – A Little-Known Love Story we explored fatty acids, membranes, and why fats are far more than just fuel. Here, we’ll zoom in on cholesterol and its transport partners and why your blood values tell a much more nuanced story than “good” or “bad.” And stay tuned: carbohydrates and protein deserve their own spotlights too.
What Is Cholesterol, Really?
Contrary to common belief, cholesterol does not store energy. It’s not made of fatty acids either, but belongs to the group of sterols, a class of substances closely related to steroid hormones. If you’re thinking of estrogen, testosterone, or cortisol, you’re spot on: these hormones strucrurally derive from cholesterol.
Why Does the Body Need Cholesterol?
Cholesterol plays multiple key roles in the body. It stabilizes cell membranes and influences how flexible and fluid they are which is an important factor for cell function and communication. Moreover, it is the precursor to bile acids, which are essential for digesting fats. Hence the name, derived from the Greek word chole for bile.
It also serves as the raw material for a range of vital hormones, including cortisol, estrogen, testosterone, and aldosterone. Even vitamin D is synthesized from cholesterol in the skin, with the help of UVB light.
And here’s a particularly fascinating fact: the brain is highly dependent on cholesterol. The protective sheath around nerve cells ,the so-called myelin sheath, is largely made of cholesterol. When this sheath breaks down, as in multiple sclerosis, serious neurological symptoms can result.
Cholesterol Production: Homemade!
The good news: we don’t have to eat cholesterol to have enough of it. The body produces about one to two grams daily on its own primarily in the liver, but also in other tissues. Only about 20 percent comes from food. And the body actively regulates this: when we consume less cholesterol, it ramps up its own production. When we eat more, it can slow things down.
Can is the key word here because it doesn’t always work that way. At some point, internal regulatory mechanisms can become exhausted or overwhelmed, for example in cases of genetic disorders or persistently unhealthy lifestyles. That’s one reason cholesterol levels vary so much from person to person, depending on diet and habits.
Transport in the Blood: Lipoproteins
Cholesterol is a lipid and like most fats, it’s hydrophobic. In other words, it can’t just float freely through the bloodstream like a tiny fat dolphin. It needs a ride and that’s where lipoproteins come in.
Lipoproteins are transport particles that consist of proteins (apoproteins) and phospholipids forming the outer shell, with a mix of triglycerides and cholesterol inside. Depending on their composition and density, they serve different roles in lipid metabolism.
Chylomicrons form in the intestine right after a high-fat meal and transport freshly absorbed dietary fats to muscles and fat tissue. The liver produces VLDL (very low-density lipoprotein) which delivers triglycerides to the body. When VLDL drops off most of these fats, a smaller, denser particle remains: LDL (low-density lipoprotein). This delivers cholesterol directly to body cells which is a useful job in principle, but its tendency to accumulate in blood vessel walls has given it a bad reputation.
In contrast, HDL (high-density lipoprotein) acts like a cleanup crew: it collects excess cholesterol from the tissues and returns it to the liver, which either reuses or excretes it.
In short: LDL is the delivery van, HDL is the taxi after the party.
LDL – The Bad Reputation
LDL = bad? Not quite. Without LDL, cholesterol wouldn’t reach the places it’s needed like cells, hormone factories, and nerve tissue. It plays a vital role in transport throughout the body. But, as so often, too much of a good thing can become a problem.
When doctors measure “LDL cholesterol,” they’re not actually counting the number of LDL particles. They’re only measuring how much cholesterol those particles carry on average. That may sound like a technicality, but it’s important. Because it’s not just the amount that matters, but also the form and behavior of these particles.
It becomes problematic when LDL particles oxidize meaning free radicals or chronic inflammation chemically alters them. Glycation also plays a role: when blood sugar levels are consistently high, sugar molecules attach to proteins in the LDL shell, a process that makes the particles more prone to oxidation. Oxidized LDL is seen by the immune system as “foreign” and is taken up by scavenger cells. These cells then form what’s known as foam cells, which can embed in the vessel walls.
Over time, this leads to plaque buildup – the start of atherosclerosis, a narrowing of the arteries that increases the risk of heart attack and stroke.
When cholesterol tries to help – but inflammation fuels the fire
So cholesterol itself isn’t the villain. It actually helps repair damaged blood vessels. But if this repair job becomes constant due to ongoing micro-injuries, inflammation, or oxidative stress then the whole system becomes unbalanced.
Chronic low-grade inflammation acts like an accelerant: it raises the demand for cholesterol, weakens vessel walls, and boosts LDL oxidation. The real danger arises when several risk factors overlap: high blood sugar, stress, smoking, sedentary lifestyle, poor fat intake, or a lack of protective antioxidants. That’s when this once-helpful building block can become a key player in the formation of arterial plaques.
Excursion: High Blood Pressure and Atherosclerosis – Who Came First?
High blood pressure can damage the delicate inner lining of blood vessels mechanically, through the constant force of elevated pressure. These tiny injuries trigger repair mechanisms that bring LDL cholesterol into play. If that LDL becomes oxidized, it attracts immune cells, which settle into the vessel wall. This can lead to atherosclerosis: the buildup of fats, immune cells, and connective tissue in the arterial wall.
But the reverse is also true: when blood vessels become narrowed and stiff due to atherosclerotic plaques, the heart has to pump harder to maintain proper blood flow. The pressure rises and high blood pressure develops.
In short: high blood pressure and atherosclerosis can reinforce each other. Which one comes first often depends on an individual’s risk profile but in the end, they’re rowing the same boat. That’s why prevention strategies are most effective when they target both together: protecting blood vessels and regulating blood pressure go hand in hand.
Aside from how much cholesterol is circulating: fewer taxis, lower risk regardless of their cargo. Because in the end, it’s not just how much cholesterol is floating around in your blood that matters, but how many particles are carrying it. This is exactly where more modern risk markers come in. They reveal more than the traditional cholesterol number.
ApoB & Lp(a) – the better markers?
If you really want to know what’s going on, forget total cholesterol and look at these two:
- ApoB (Apolipoprotein B-100): Each atherogenic lipoprotein particle (VLDL, LDL, IDL, Lp(a)) contains exactly one ApoB. So the ApoB level tells you how many potentially risky particles are circulating – regardless of how much cholesterol each one carries. If you paid attention you know that Chylomicrons also carry apoB albeit a shorter version. However, they are only in your blood if you have eaten recently and blood tests are carried out fasted (no food for 8-10 hours).
- Lp(a) (Lipoprotein little a): Structurally similar to LDL, but with a dangerous addition – Apolipoprotein(a). This variant is genetically determined, barely influenced by lifestyle, and particularly atherogenic. And the kicker (for better or worse): Lp(a) isn’t even measured in standard cholesterol tests. So, you could have “perfect” LDL levels – and still carry a hidden risk.
This variant is carried by 20–30% of the population, so it’s not exactly a niche issue. And that raises an intriguing question: why would the body even do that? Why produce a lipoprotein so strongly linked to cardiovascular disease?
Maybe because it used to be useful.
Lp(a) resembles a rescue helicopter equipped with special gear and a throw line: it can quickly fly to where a blood vessel has been damaged and help with the repair. Apo(a) resembles the enzyme plasminogen, which normally helps dissolve blood clots. Researchers therefore suspect that Lp(a) played an evolutionary role in wound healing and clotting, especially in times when injuries were common and survival depended on how quickly bleeding could be stopped.
Women tend to have slightly higher Lp(a) levels on average than men. That, too, could be biologically meaningful: the greatest risk of bleeding in a woman’s life was (and still is) childbirth. A fast clotting response could mean the difference between life and death. What we now see as a risk factor may once have been a survival advantage.
In a world full of low-grade inflammation, chronic stress, and constant metabolic stimuli, this rescue helicopter gets called out far too often – even when there’s no real emergency. And that’s when a once protective function becomes a burden on the arteries.
What does that mean for you?
If Lp(a) was originally a useful repair helper, then maybe the key isn’t so much to lower its level. Either way it’s considered relatively stable and not influenced much by lifestyle. Instead, the goal should be to prevent the body from needing to send it out so often in the first place.
And that brings us to one of the most important influencing factors of all: inflammation.
Because particles like LDL, Lp(a) only become a problem in an inflammatory environment. That’s when they attach to vessel walls, oxidize, get “eaten” by immune cells, and end up embedded in the arteries.
That’s why it’s so important to pay attention to the quality of your diet, to move your body, to get good sleep, and to manage stress. It’s trendy wellness advice but you’re actively shaping the environment in which your blood vessels either age or manage to stay young.
So let’s take a closer look: what exactly is inflammation? And how can you tell if it’s quietly smoldering inside you?
Excursion: Inflammation and Fat Metabolism – Friend or Foe?
The word inflammation brings to mind swollen red patches, throbbing pain, and feverish drama. And yes, that’s exactly what classic acute inflammation looks like. Think cuts, infections, or sprained ankles. The immune system jumps into action like a well-trained emergency crew: it sends out messengers, opens blood vessels, allows immune cells to flood in, and clears out the mess. Once the job’s done, the team retreats, the body heals, and everything calms down again.
But what happens when that retreat never comes?
That’s when we enter the territory of chronic, low-grade inflammation. No drama. No obvious pain or hot, swollen area. Just a body stuck in constant alert mode. These processes can smolder beneath the surface for years. And that’s what makes them so sneaky. They drive oxidative stress, mess with repair processes, and increase the chances that otherwise harmless substances like cholesterol start showing up in the wrong places.
This type of inflammation is often fueled by a mix of modern-life stressors that overwhelm the system over time: chronically elevated blood sugar, a diet full of ultra-processed foods, too little movement, poor sleep, or ongoing emotional strain. Environmental toxins, lingering infections, or an overloaded gut can add to the fire.
The good news is there’s a lot that helps to calm things down. Regular movement. A colorful, plant-rich diet. Enough Omega-3s. Sleep. Sunlight. Slow breaths. True breaks. And the occasional honest conversation. (Let’s be real: a well-placed “no” often helps more than the seventh to-do list.)
Inflammation, then, isn’t the enemy. It’s a signal. A biological SOS that says: Something needs care. And when we learn to listen, something deeply healing can begin.
Side note: Funny, isn’t it? We often rush to suppress acute inflammation- ice swollen ankles, lower fevers – even though that’s our immune system doing exactly what it’s supposed to do (I am not denying that acute inflammation can escalate, too). But meanwhile, the slow-motion car crash of chronic inflammation quietly builds in the background… and we barely notice we’re fueling it.
Excursion: How do I know if I have low-grade inflammation?
The tricky thing about chronic, low-grade inflammation is: you don’t feel it. No fever, no redness, no classic pain. And yet, the body can remain on high alert for years. So how do you know if something’s quietly smoldering in the background?
There are a few clues if you know where to look. Certain inflammatory markers can be measured in the blood, most notably CRP, or more precisely: hsCRP, the high-sensitivity C-reactive protein. It spikes during acute inflammation, but in this more sensitive version, it can also detect low-grade, chronic processes. Values below 1 are considered low risk, above 3 are elevated though always to be interpreted in context.
Other lab values can also hint at inflammation, such as the neutrophil-to-lymphocyte ratio or elevated triglycerides paired with low HDL. But no single value can definitively prove or rule out chronic inflammation.
Sometimes, inflammation makes itself known indirectly through fatigue, diffuse pain, poor recovery after exertion, low mood, or unexplained weight gain. None of these are dramatic on their own but taken together, they can be a signpost.
So if you feel like your body is somehow out of balance, it might be worth checking in on those inflammatory markers. Not out of panic but out of curiosity and care. Because the earlier you notice something stirring inside, the easier it is to course-correct.
I wanted to show you what an amazing system your body is. We often look outward in search of fascinating things to discover but there’s this spectacular organism you’re wired into, always with you, quietly doing its job. It deserves admiration, care, and deep respect. And no matter what’s going on, your body is always trying to do right by you.
I hope I’ve convinced you how unfair it is to pin all the blame on cholesterol.
It’s neither the villain nor the hero of the story but rather a multifunctional building block of life that only becomes a problem in the wrong context. The molecule itself isn’t the risk. It’s how many of them are circulating, how they’re packaged, whether they oxidize, and whether your internal environment promotes inflammation. If you’re only looking at total cholesterol, you’re only seeing half the picture and missing the chance to take smarter, more personalized steps for prevention. Cholesterol isn’t the end. It’s the beginning of a much more fascinating journey through metabolism, immunity, and modern risk diagnostics.
Practical Tips for Supporting Your Fat Metabolism
The good news? You have more influence over your lipid metabolism than you might think without needing statins. (That said, don’t stop any medications on your own! But ideally, find a doctor who’s at least heard of ApoB.)
A lot starts with what you do every day. Movement, for instance, works like an internal cleanup crew and reduces silent inflammation. A diet rich in colorful vegetables, healthy fats, and low in sugar also supports a calmer, more resilient system. Fiber plays multiple roles: it feeds your gut microbiome, helps regulate blood sugar, and binds bile acids in the gut which can help lower cholesterol levels.
Try to avoid trans fats, which are found in industrially hardened oils and disrupt fat metabolism on many levels. And if you’ve never had your cholesterol checked, remember: the classic total cholesterol number doesn’t tell you much. More informative markers include ApoB, LDL-P, and Lp(a), which give you a clearer picture of how many atherogenic particles are actually circulating.
Some people also use plant sterols or niacin. These can be helpful, but not for everyone, and never without guidance. As so often, the smartest hacks are the least spectacular. But they work, if you stick with them.
My Personal Case Study
I’ve tried a lot of things including keto. Afterwards, I had my labs done: my LDL has always been on the higher end of the normal range, but my ApoB is completely unremarkable, and my triglycerides are in a good place. What is genetically elevated for me, though, is Lp(a). That’s why I no longer just look at numbers in isolation but at the bigger picture of my metabolism. Because my transport taxis are a bit stickier than average they could get stuck in the vessel walls. That part I can’t change.
My focus now is on keeping inflammation low and staying metabolically flexible. I practice “intermittent intermittent fasting”. I generally like to eat a lower-carb diet, because it keeps my hunger signals calm and helps me stay steady throughout the day. But not during the luteal phase of my cycle. And especially not in the final week.
I eat fats, but intentionally. I go for high-quality plant-based fats like nuts, olive oil, avocados, and seeds but I avoid large amounts of sunflower oil and the like. Animal products are part of my diet too. I do not exclude anything in fact. Not even cake as you know from my front page. I do prefer fermented dairy and occasionally organ meats, for their nutrient density.
What I consciously include on a regular basis: fatty sea fish twice a week for Omega-3s (EPA and DHA). Plenty of vegetables, some fruit. And a few times a week, chia or flaxseed pudding for fiber, plant-based Omega-3 (ALA), and satiety.
I don’t believe in the perfect diet and I certainly don’t have one. But I do believe in self-observation, good data. And in the idea that our metabolism thrives on variety grounded in rhythm.
Cholesterol isn’t the villain it was made out to be but it doesn’t get a free pass either. It’s a vital building block that only becomes problematic in the wrong context. Looking at your numbers in isolation tells only half the story; understanding them in relation to inflammation, metabolism, and lifestyle tells the other half.
And there’s another angle worth exploring: are you a “hyper absorber,” someone whose cholesterol levels rise noticeably with food intake? I suspect I might be and I’ll be testing this in an upcoming mini-series.
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