Miranda has a Master's in Human Nutrition from Christian-Albrechts-Universität and a passion for promoting accurate nutrition information.
Few nutrients have created as much controversy over the last few years as cholesterol.
It seems that every time you turn around, there is some new study and a flashy new media headline making extravagant and contradictory claims about the role of cholesterol in human health. One minute cholesterol is toxic, the next, part of a healthy diet.
It’s seriously confusing!
Here, I want to cut through the confusion. Let’s look at the basics of cholesterol, what it is, what it does in the body, why some scientists think it’s dangerous, why others don’t, and what it all actually means for you, your diet, and your health!
Cholesterol is a natural, fatty compound made by your liver whose main job in your body is to keep your cell membranes healthy.
What Is Cholesterol And Why Is It Important?
Cholesterol is a natural, fatty compound made by your liver. Its main job in the body is to keep your cell membranes healthy. Your cell membranes are thin layers of fat that coat each of your cells and keep them separated from each other and the outside world. Basically, they are what make a cell a cell and not a little pile of goop.
To be healthy, your cell membranes have to have just the right consistency. If they are too runny, like oil, they cannot hold a shape and everything from inside your cell will leak out and it will die. But if it is too stiff, like lard or shortening, nutrients and waste products can’t get into or out of the cell, and it dies as well. Cholesterol has a unique consistency, which allows it to keep your cell membranes the perfect firmness when it's mixed in.
As if this job were not enough, cholesterol is also used to make other important molecules that regulate:
- Digestion and absorption of fat from food
- Sexual health and reproduction
- Brain function
- Bone health
- Immune function
Simply put: cholesterol is essential for keeping your body working properly. You cannot live without cholesterol.
Simply put: cholesterol is essential for keeping your body working properly. You cannot live without cholesterol.
Your Cholesterol vs. Cholesterol In Your Food
At this point, you are likely thinking: “You cannot live without cholesterol” seems pretty conclusive - how can there be any question about whether it is safe to eat or not!? I need it!
Ah, but the problem is, you need it too much.
See, cholesterol is so important for keeping the human body alive and healthy that it was too risky to let the food supply decide how much was available. If you left it up to the diet and you had to wait a couple of days for a meal with cholesterol in it, your levels could drop too low and you could die. To make sure that could not happen, the human body evolved a way to make its own cholesterol without any help from food. And it did a great job; the production process works perfectly. You make make all the cholesterol you need, always.
So you need cholesterol, definitely. But you just as definitely do not need it in your diet.
Okay. But that does not mean that having it would necessarily do you any harm, does it? Having a little extra cholesterol to work with without having to make it yourself could be a good thing, right? Maybe you could just make a little less yourself, save yourself some time and energy making it?
Seems totally reasonable. When scientists started studying that assumption, though, the data just didn’t add up. Study after study was able to find a link between the amount of cholesterol people ate and the amount of cholesterol in the blood. Blood levels weren’t kept steady by the body making less to make up for the cholesterol from food.
Still not necessarily a problem, though. I mean, maybe a little extra just gives you some back-up cholesterol in case of emergencies or something!
But then, we discovered atherosclerosis.
Atherosclerosis is a buildup of cholesterol and white blood cells, together referred to as plaque, inside the walls of your arteries. And these plaques are bad news for your health. They make your arteries narrower and narrower, forcing your heart to pump harder to be able to get your blood to flow normally, causing high blood pressure and putting strain on your heart. And, if there is so much cholesterol in the artery wall that the wall breaks open, it can cause a heart attack or death.
Studies began showing that the amount of plaque in arteries could be directly linked to the amounts of cholesterol in the blood. They could even conclusively show that the body required nothing more than high levels of blood cholesterol to start making atherosclerotic plaques in arteries.
The case seemed closed. Blood levels are raised when you ingest cholesterol. Elevated blood cholesterol levels cause atherosclerosis. Atherosclerosis causes high blood pressure, heart failure, heart attacks and death.
This is where we were for a long time. This is the point that American Health Association and other government organizations set their low limits for cholesterol intake each day and advised avoiding cholesterol-rich foods, like eggs.
Why all the new controversy now? New studies suggesting that the picture painted about high cholesterol might be a bit more complicated than previously imagined.
There are two main scientific advances that have caused scientists to begin debating the role of cholesterol in the diet again:
- The recognition that cholesterol needs to be packaged in a very specific way in the blood in order to cause atherosclerosis
- Dietary fat can drive up the amount of cholesterol your body makes on its own
The first of these you’ve probably heard a lot about. It’s commonly talked about as LDL (or bad) cholesterol vs. HDL (or good) cholesterol.
See, since cholesterol is a fatty molecule, it has to be packaged into little waterproof protein-covered packages to be able to flow through your water-filled bloodstream -- otherwise, it would try to separate off by itself, like oil does when you mix it with water. There are several different protein-packages available to cholesterol. Two of the most important are “LDL packaging” and “HDL packaging”. In LDL packaging, the proteins form a pretty big box for the cholesterol to sit in; they aren’t bound as tightly together and they give the cholesterol room to sneak in and out. In HDL packaging, the proteins keep the cholesterol on lockdown; they are bound tightly together and keep all the cholesterol tightly wrapped up.
The discovery that only cholesterol being transported in loose LDL-packaging was really able to sneak into the artery walls and cause atherosclerosis created a divide in the scientific community. Some argued that this discovery proved dietary cholesterol wasn’t really the problem in driving atherosclerosis, since you could, theoretically, have all the cholesterol you want in your blood, as long as it’s in HDL packaging. The problem, actually, was some people’s livers deciding to put cholesterol into the wrong package! So, really, we shouldn’t be looking at dietary cholesterol, but at optimizing liver health to keep cholesterol packaged properly.
Other scientists pointed to the strong data showing clear links between levels of cholesterol in the diet, blood cholesterol levels and heart attacks. They pointed out that as long as that relationship exists, it was unethical to suggest eating cholesterol is safe, even though it theoretically could be with optimal liver health.
The debate became even more heated when studies investigating the role of different fats in the body showed that high concentrations of fats, especially saturated and trans fats, could cause the body to make too much cholesterol of its own, and package it in LDL proteins. This meant that your diet could elevate your LDL-packaged cholesterol without there being any cholesterol in it at all!
Scientists who thought the first line of evidence suggested cholesterol was safe to eat found this to be a nail in the coffin of the anti-cholesterol argument. If other foods can increase cholesterol levels, cholesterol cannot be the bad guy. Maybe it was just fat in the diet, in general, that had been the problem the whole time! Maybe we were doing people a disservice by telling them just to avoid cholesterol because saturated and trans fat might be just as bad for their blood cholesterol levels!
And this has been the center of the controversy for the last few years - is it dietary cholesterol itself that is the problem, or dietary saturated and trans fat, or both?
Not if cholesterol is involved in causing atherosclerosis. Not if cholesterol itself is inherently dangerous or inherently good. The debate is just - is dietary cholesterol the primary dietary factor responsible for raising blood cholesterol or not.
That’s a much narrower area of debate than the context-less media headlines make it seem, huh!
From Debate To Dinner
Unfortunately, the debate rages on. We still do not definitively know if dietary cholesterol is the biggest player in driving up levels of poorly packaged LDL-cholesterol in the blood or not.
So, what do you do in the meantime? How do you decide what to put on your dinner plate? Should you avoid cholesterol? Or is it better to avoid saturated fat? Or trans fat?
The short answer is: it doesn’t matter!
Yeah! It doesn’t matter! See, only sources of cholesterol in the diet are also the number one source of saturated fat and significant source of trans fat in the diet too!
If you want to avoid any of these nutrients in order to keep your blood cholesterol levels low, you should avoid the same four foods!
- Processed junk food containing meat, dairy, eggs or refined oils
Seriously? It’s that simple?
With all the controversy, and confusion, and contradictions, it all comes down to the same changes in your diet anyway?
Now, that is not to say atherosclerosis is just that simple, or that no other factors can play a role in developing plaques in your arteries. Smoking, lack of exercise, excess processed sugar all play their roles, for example.
As far as high levels of poorly packaged LDL cholesterol in your blood, though - yeah - that is more or less it.
But you don’t have to take my word for it!
You can check out these resources for supporting evidence, additional lines of argument leading to the same conclusion, and additional in-depth discussions:
Tabas, Ira. “Cholesterol in health and diseases.” Journal of Clinical Investigation 110.5 (2002): 583-590. DOI: 10.1172/JCI16381.
Gundy, Scott M. “Does dietary cholesterol matter?” Current Atherosclerosis Reports 18 (2016): 68. DOI: 10.1007/s11883-016-0615-0.
Berger, Samantha et al. “Dietary cholesterol and cardiovascular disease: a systematic review and meta-analysis.” American Journal of Clinical Nutrition 102.2 (2015): 276-294. DOI: 10.3945/ajcn.114.100305.
Eckel, Robert H. “Eggs and beyond: is dietary cholesterol no longer important?” American Journal of Clinical Nutrition 102.2 (2015): 235-236. DOI: 10.3945/ajcn.115.116905.
Dinu, Monica et al. “Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies.” Critical Reviews in Food Science and Nutrition 57.17 (2017): 3640-3649. DOI: 10.1080/10408398.2016.1138447.
Or browse the videos here: https://nutritionfacts.org/topics/cholesterol/
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
Miranda Poenicke (author) from Germany on November 08, 2017:
Thank you so much for your positive comment, Liztalton! I find it to be a fascinating topic, as well!
It's interesting to hear that you got your cholesterol down on a high-fat diet. You must be doing a great job of emphasizing healthy fats! Awesome work! :)
Liztalton from Washington on November 07, 2017:
Great hub and a very interesting debate. I eat a low carb, high fat diet and people often comment that my cholesterol must be through the roof. But since going low carb, it's gone down. With all the controversy surrounding cholesterol, you did a great job sorting through a lot of debate.