Updated: Nov 17, 2019
If you find yourself in a conversation about heart disease or atherosclerosis you will more than likely find yourself talking about cholesterol, especially the lipoprotein called LDL. For the better part of 70 years LDL has dominated the conversation about cardiovascular disease, solely because it has been blamed for the disease. If you follow my blog, you know a lot about why it has been wrongly blamed. I believe it is time that we redeem LDL. Rather than discussing the evidence of why it isn’t bad and is not the cause of heart disease, we will instead discuss how beneficial it is for the body.
If LDL was such a problematic entity and it had the ability to kill us by causing heart disease so readily, then evolution would have selected out LDL a long time ago. Those with higher LDL would not have survived as well as those without it and those high LDL genes would have been weeded out. However, LDL was preserved by evolution and when we start to look into all the roles of LDL in the body we start to see why.
LDL is low density lipoprotein. It is a vesical for carrying around cholesterol. Cholesterol is not dissolvable in water and cannot travel through the blood (because blood is half water) so it is packaged up into LDL, and other lipoproteins, to be transported. LDL has an identifying protein on it, therefore it is called a lipoprotein.
If you ate no cholesterol in your diet your body would make about 1.5 grams of cholesterol per day. That’s how important it is. It then would get packaged up into various lipoproteins and shipped out throughout the body. So, what kind of things does it do once it gets out into the body?
One thing that it does is aid in defense from infection. LDL is able to bind to bacteria and endotoxins and neutralize them before they can negatively affect the host. (1,2) In a previous blog, I discussed the possibility that LDL on a blood panel can go way up on a ketogenic or carnivore diet, why this can happen, and why it isn’t a problem. Dave Feldman of cholesterolcode.com has labeled these people as “lean mass hyper responders”. One thing that we see among these people with really high LDL is that getting sick is a rare thing. I would postulate that this is because there is much more LDL available to protect them from bacterial infection.
I am a lean mass hyper responder and my LDL is over 400. I have not been sick since January 2016 (I hope I am not jinxing myself). Since being on a ketogenic diet my LDL has been above 200 and I have noticed this effect. When I went full carnivore, my LDL went up to over 400. I saw another benefit when this happened, which I will discuss later.
Another job of LDL is cellular membrane function and repair. Cholesterol plays a very important role in cell membrane structure providing strength and flexibility to the cell. (3) It is also essential for the communication between cells. Without that communication, our cells would not be able to come together and form tissues, tissues wouldn’t be able to become organs, and organs would be able to function together as a human. Cholesterol is critical for maintaining proper cell communication and repair, and studies have shown that the cholesterol packaged in LDL can repair the damaged nerve cells (which are used for communication) of demyelinated nerves. (4)
Moving on, a we discussed the main job of LDL is the delivery of cholesterol. Cholesterol is the backbone for all our hormones and without LDL transporting cholesterol we could not make hormones. As cardiologist Nadir Ali says, “Women would not be as beautiful, and men would not be as handsome without cholesterol”. But it is more than just our sex hormones. The body uses cholesterol as the base for the synthesis of all steroid hormones. (5)
Speaking of steroid hormones, Vitamin D is technically a steroid hormone. Vitamin D2 is ergocalciferol and Vitamin D3 is cholecalciferol, both are converted to calcitriol in the body. It is well known that our body synthesizes Vitamin D when we are exposed to sunlight on our skin. However, if we do not have the other raw materials we need to make it then we will not get enough Vitamin D. Having enough cholesterol present is essential for us to make adequate amounts of Vitamin D.
Once Vitamin D is made it is transported around the body in LDL, as are all the fat-soluble vitamins. (6) They are reliant on LDL for transport because they are not soluble in water (blood). Long term use of the LDL lowering drug PCSK9 inhibitors has been shown to result in decreased levels of Vitamin E. (7)
Yet another role of LDL is to deliver energy to our body. It makes sense that if we restrict carbohydrates that the body will have to burn more fat and deliver that fat to our cells to be used for energy. This could explain why some people on a ketogenic diet experience really high LDL, the body is delivering energy. This idea is best outlined by Dave Feldman in the talk he did at Low Carb Down Under.
Next, we need to talk about muscle function. LDL delivers cholesterol to muscles because it is essential for muscle repair. (8) This is critical for rebuilding stronger muscles after working out. If we don’t have cholesterol delivered from LDL then we cannot build strong muscles. Given that muscle mass is a huge determinant of longevity, (9) a continuous supply of cholesterol from LDL is key to health.
The delivery of cholesterol by LDL is also essential for the proper function of insulin receptors on cells. (10) Aside from the research showing this, I have personal experience with this. I had been on a ketogenic diet for many years and, as I said before, my LDL would hover around 200. When I went carnivore, my LDL has been consistently over 400. I am type 1 diabetic and have to administer my own insulin. I felt that my insulin seemed to work better when I went carnivore and had no idea why that would be. At first, I thought it was that I had eliminated a plant toxin that may have been interfering with insulin or that I had reduced inflammation and therefore required less insulin. But when I learned that cholesterol was essential for the health of insulin receptors on cells and the fact that my LDL went way up on carnivore, this made sense as a plausible mechanism.
Lastly, we need to talk about the ability of LDL to prevent vascular calcification. Yes, you read that right. It has been blamed for causing atherosclerosis, but it can actually prevent it. It does this through another fat-soluble vitamin, K2. LDL delivering cholesterol is essential for making Vitamin K2, which is key for depositing minerals where they need to be and not where they don’t, like in the lining of an artery. K2 stimulates the matrix Gla protein that inhibits the formation of calcium plaque. (11) LDL lowering medications have been shown to stimulate atherosclerosis, not enough K2 being made and delivered when taking these drugs is one mechanism behind this. (12,13)
So obviously there are major benefits to having enough LDL in our blood to deliver cholesterol and fat-soluble vitamins to our body. Lowering it to the lowest possible number may not be a good idea. To illustrate this let’s look at what happens to people with abetalipoproteinemia, a condition where the body cannot absorb fat which results in very low levels of LDL. These people often have recurrent infections because LDL cannot help in defense of bacteria, blindness because fat soluble vitamin A is not delivered by LDL, ataxia because of demyelination of nerves due to lack of cholesterol, and higher rates of liver cancer. (14) These people also tend to die earlier, in their 4th or 5th generation.
Now, the devils advocate side of this is to say that yes LDL does a lot of beneficial things in the body and we need it at normal levels, but does it become problematic when it gets too high? For this we need to look at people who have familial hypercholesterolemia, a condition where they have very high LDL levels. A study that tracked a family with a genetic line of familial hypercholesterolemia for over two centuries found that, “the precocious onset of cardiovascular disease and the bad prognosis of familial hypercholesterolemia have been overemphasized”. They also found that the condition “may have conferred a survival advantage when infectious disease was prevalent”. (15) These people didn’t die any sooner that those with “normal” LDL levels.
I know I have seen benefit from having higher LDL, such as the less frequent sicknesses and the better insulin response I mentioned before. And if very high cholesterol doesn’t seem to be an issue as far as longevity goes then why not reap the benefits of it. When looking at a lipid panel a high LDL is perfectly fine, and as we’ve seen can be beneficial, as long as triglycerides are low, HDL is normal or high, and we have low markers of inflammation and insulin resistance. The good news is that a ketogenic or carnivore diet will create a lipid/blood panel that looks this way. Hopefully now you can see that the demonization of LDL was wrong and unnecessarily lowering it has created poor health.
Stay healthy out there!
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