Like many you may be concerned about your cholesterol. You have probably heard on the news that eating saturated fats will raise your “bad” cholesterol. No doubt you are concerned about the growing rates of heart disease. Well hopefully this article will help you understand what cholesterol is and why you should not be afraid of it.
We may know the word cholesterol but how many of us understand its purpose? Cholesterol is a molecule with several roles in the body. I won’t go into great detail about the chemical makeup. There was a website from Chris Masterjohn, PhD who is an expert biochemist and has spent years studying cholesterol. He has an amazing mind for detail and I love reading his work. I will refer to some of his work throughout this article. Unfortunately the website is gone, so I cannot link to it anymore. He is still a good resource and you can learn more from him here: chrismasterjohnphd.com
I have included the cholesterol pathway. It illustrates how our body makes cholesterol as well as what happens when we take statin medications like Lipitor. As you read this you may want to refer to it again to get the big picture.
In describing cholesterol’s function Masterjohn states, “It is a critical component of cell membranes, the precursor to all steroid hormones, a precursor to vitamin D, and the limiting factor that brain cells need to make connections with one another called synapses, making it essential to learning and memory.” In other words, it has an important role throughout the body. A lot of my patients deal with hormone related issues and if you are not eating healthy fats and making enough cholesterol you will have a problem making enough hormones. Now, let’s breakdown each part a little further.
The cell membrane is the structure around the entire cell composed of a double layer of lipids called phospholipids. Intertwined within the membrane are proteins and cholesterol. It is a selective structure only allowing certain substances in since it is composed of lipids. I am sure most of you have seen how oil and water do not mix. This is how the cell structure works with lipid membrane.
The role of cholesterol in the cell membrane is to help maintain the cell’s structure. It makes up about 20% of the membrane. Without it the cell’s integrity would be compromised. The membrane would be too mobile and permeable to other molecules. It also keeps the membrane from becoming to rigid. It helps it to be just right. Furthermore, it participates in cell signaling or the ability for our cells to communicate with each other. It does this by locking in the proteins that communicate with other cells or allow the flow of substances in and out of the cell..
Cholesterol is also present within the cell. There exists within our cells structures called organelles. These structures all have varying jobs. Some of them you may recognize such as the endoplasmic reticulum and mitochondria. The membranes of these structures also have a varying amount of cholesterol.
Next stop the brain. Cholesterol is abundant within our brain and nervous system. Our nerves are covered with a fatty sheath called myelin that is partially composed of cholesterol. This sheath allows for the fast transport of signals. In fact approximately 25% of our cholesterol is in our brain!
It has an essential role memory. It helps with neuroplasticity, the ability of your brain to adapt and form new synapses. A synapse is a new connection. When we learn something new such as playing the piano synapses are being made with memories, muscular control, hearing, etc. Our brain constantly changes for the better or the worse. But cholesterol is crucial in this process.
Digestion. Without cholesterol we would not be able to create bile salts which helps us emulsify fats that we consume. Without that we cannot digest them. Bile salts are created in the liver and stored in the gallbladder. They are released into the small intestine and then most of it is reabsorbed later on but some is excreted. However, none of this is possible without cholesterol. It is the precursor to bile salts.
The all important vitamin, Vitamin D. We usually think of being able to get vitamin D from the sun but we rarely think of the process it takes to create it in the body. The sun doesn’t magically give us vitamin D by just basking in it. Sunlight turns cholesterol into vitamin D. That’s right cholesterol is the precursor to vitamin D. So what does vitamin D do?
Most of us have heard the warnings and have been admonished to take vitamin D because it helps with calcium metabolism to strengthen bones. But it has many other roles such as immunity, blood sugar regulation and cardiovascular health. Some even call it a hormone. Sad news is in the US approximately 70% of us are deficient in vitamin D. We just do not get enough from our diet or spend enough time in the sun. When we are outside we tend to put on sunblock. Sunblock that has a SPF of 8 or more blocks the production of vitamin D. I will write another article soon on vitamin D. And without enough cholesterol we will not be able to make vitamin D regardless of how long we spent basking in the sun.
Lastly, steroid hormones. Cholesterol is the precursor to all steroid hormones. These hormones are vital. Hormones are chemical messengers that instruct cells to do certain things. You will have undoubtedly heard of many of these hormones. Even the word steroid should give away one of them, testosterone. But there are several others such as progesterone, estrogen, aldosterone, and cortisol. These hormones play roles in blood sugar regulation, mineral balance, blood pressure regulation, menstrual cycle, reproduction, tissue growth, and the list goes on. As you can see cholesterol has many functions and is vital to our health. Now that I have listed the functions you may want to refer back to the pathway to get a better picture of it.
So where do we get cholesterol? How do we make it? I am going to take a bit of a tangent, it is relevant so bear with me. This is vitally important to understand. Not only for cholesterol synthesis but for health in general. Fats that we eat to do not equal fats that we store. This is frustrating and maybe confusing. I know it is very frustrating to me as a physician. In biochemistry there are two terms I would like to define: exogenous and endogenous. The prefix “exo” means from without or outside. The prefix “endo” means from within or inside. The meaning of “genous” should be easy to figure out. It is from the same origin as Genesis, the first book of the Hebrew Bible. It is a Greek word which means origin or beginning. Therefore, exogenous means originating from outside the body. Endogenous means originating from within the body. The majority of cholesterol is made endogenously, or within the body not absorbed from diet.
This is an important concept because since the 1960s we have been told that fat is bad. This is one of the reasons I am writing an article on cholesterol. Cholesterol has been singled out as devastating to our cardiovascular system. That it is the cause of heart disease. But this is simply not true. Furthermore, we all know obesity leads to many complications including heart disease. We have seen the store shelves filled with items that say “low-fat” or “fat-free.” It would be nice if all we had to do was to cut out fat in our diet so we could trim our own fat. But exogenous fat is not at the root of our obesity epidemic. It is our carbohydrate intake specifically refined carbs such as all our flours, sugar, and corn syrup we love to eat. This quickly overwhelms our body with more food than we need and so our body shunts it into storage, aka, fat. I am sure I will write endlessly on this subject so most likely there is much more to come.
Alright tangent over. As you can see cholesterol is needed all over the body. It would be difficult to get enough cholesterol from our diet to supply this need, therefore our body makes it. Eating cholesterol rich foods may be helpful and lower the burden on the body, but overall, there is little effect from dietary cholesterol. You heard that correctly, there is little effect on our cholesterol levels from eating foods rich in cholesterol. Which debunks a myth that eating cholesterol rich food raises blood cholesterol levels.
However, this myth started a major problem. Cholesterol containing foods like eggs, butter, and lard were maligned and we were discouraged from eating them. We replaced these foods with vegetable oils which contain a large amount of polyunsaturated fatty acids or PUFA. They contain a high about of omega-6 fats, a PUFA. I am sure you have seen plenty in the news about the benefits of omega-3 fats, also a PUFA. Usually they will tell you to take fish oil supplements, which creates another problem. But our bodies do not need that many PUFAs. PUFAs can contribute to oxidative stress in our bodies. Another reason antioxidants are all the rage.
But what about bad cholesterol vs good cholesterol? This is referring to LDL vs HDL. Let’s talk about these molecules a bit. LDL stands for low density lipoprotein and HDL stands for high density lipoprotein. A lipoprotein is a molecule that consists of proteins and lipids. The membrane consists of PUFAs. Because fats do not mix with water lipoproteins are used to carry them. Therefore, lipoproteins carry cholesterol, fat, vitamins A, D, E, and K, and coenzyme Q10. Masterjohn describes them as being like a bus and the protein is like the driver which interacts with different cells to determine where it goes, parks, and drops off the passengers. So it is incorrect to call LDL, LDL cholesterol. It carries cholesterol and other molecules.
When we digest fats they are carried via lipoprotein. The liver also takes these fats and lipoproteins and repackages them and sends them off to their various destinations. LDL is primarily responsible for transportation of cholesterol. They transport cholesterol to cells where they are taken up. LDL not taken up are prone to oxidation which will be discussed later. HDL is responsible for taking the free cholesterol from the tissues and gives them to LDL particles or to the liver. HDL trades the cholesterol for triglycerides and vitamins.
Studies have shown that high LDL leads to increased risk of atherosclerosis or plaque build up in blood vessels. However, this is an oversimplification. When doctors order blood tests to measure cholesterol, it measures it by weight not by number of LDL particles. There are different particles with different roles. Studies have linked one particle to atherosclerosis. This particle is small. The larger LDL particles are not linked to atherosclerosis and are considered safe. The idea is the smaller particles are more prone to oxidation. Cholesterol containing foods such as eggs make the particles bigger and less prone to oxidation. So having a high LDL count is not necessarily bad. The particles need to be looked at it. In fact, you can have low cholesterol but have high LDL particles. (1) However, in most of the population consuming cholesterol containing foods has little to no effect on blood levels. In some, cholesterol goes up but the LDL particles stay the same they only get bigger and safer.
Not eating cholesterol containing foods has other negative effects as well. Cholesterol is not the only nutrient within these foods of course. Arachidonic acid, a fat that has also been maligned as inflammatory is contained within these foods. It is one of the most essential fats we need to function especially in children, women, or those recovering from an injury. This can be produced from Omega-6 PUFAs as well. This also illustrates the need for a variety of foods in your diet and a balance between Omega-6 and Omega-3 fats. Signs of Arachidonic acid deficiency include infertility, scaly skin, and hair loss.
A food group that is often overlooked in our meals is offal. Offal refers to organ meats like liver, kidney, and heart. Foods not typically found in most American diets. Often because the flavor is hard for many. However, these foods are among the most nutrient dense. Chris Kresser in his book, Paleo Cure, talks about the importance of liver in your diet. He has diagrams showing the nutrient density of the liver compared to vegetables, grains, and other cuts of meat. It is a fantastic superfood. But you are like me and hate the taste, you can try mixing it into ground beef for your favorite dishes, try it in a bone broth, or if that is not good enough you can try cutting it into small pieces and freezing it and then swallowing them like pills. Another option is to buy dessicated liver, Radiant Life has a product. They also sell fermented cod liver oil which has been shown to be of high quality. The fermentation helps prevent rancidity.
Eggs have gone in and out of popularity. But let this be final, eggs are healthy and great addition to any diet. Eggs not only include cholesterol as I stated earlier, they also include Vitamin K2, Choline, Vitamin B7, and protein.
Cholesterol and Heart Disease
We have talked about what Cholesterol is and where cholesterol comes from but lets go more in depth with its controversial “role” in heart disease. Cholesterol is blamed for heart disease, stroke, alzheimer’s, and many other things. Saturated fats have been maligned for many decades. So what is really going on?
So if the amount of cholesterol we consume has little effect on blood cholesterol levels, what is the problem? It really comes down to oxidation. Polyunsaturated fatty acids or PUFAs are fatty acids that are prone to oxidation. We produce antioxidants to combat oxidation in our body, but they can only do so much. Masterjohn gives a good analogy for clarification. “If you use a jar of oil, you open it, exposing the PUFA within it to the oxygen in the air, but quickly put the cap back on and put it back in the fridge. What would happen if you opened the jar and let it sit on the table at room temperature? Over time, the limited amount of antioxidants in the oil would run out and the PUFA would begin to oxidize. The oil would go rancid. Pumping LDL in to the blood but letting it sit there circulating round and round exposed to oxidants rather than taking it into the shelter of the cell is like opening a jar of oil and leaving it on the table.”
Oxidized LDL cholesterol is the problem. The membrane of the LDL particle contain PUFAs. They have a limited supply of antioxidants as do the cells they become attached to. When they run out the oxidized PUFAs begin to damage other parts of the LDL particle. As it becomes damaged it infiltrates the blood vessel wall and activates immune cells called monocytes turning them into macrophages and then into foam cells which makes up the plaque that fills the endothelium (the blood vessel layer closest to the blood) of the blood vessel. (2,3)
So where are we getting all these PUFAs? These do come from our diet. The highest concentration of PUFAs is in our vegetable oils, the oil we most commonly use. These include canola oil, corn oil, sunflower oil, peanut oil, and the simply named vegetable oil. Pretty much it is any oil that is liquid at room temperature. That includes olive oil. Yes, it is considered a healthy oil but if you are not careful and place it in a dark container or in the fridge it will oxidize as well. Some of these oils have deodorizers added to them because they have already oxidized. Rancid oil does not have a pleasant smell. Unfortunately, we have been encouraged for over 50 years to consume a lot of these types of oils.
As I noted before, not all LDL cholesterol is alike. There are different particle sizes. Most doctors do not order labs that breakdown the LDL particles. LDL can be high and still safe. Small, dense LDL particles oxidize much more rapidly.(4) The larger LDL particles are bigger and safer. So it is incumbent upon the physician to order a comprehensive cholesterol test to measure the values of each particle.
Let’s talk more in depth about the oxidation of these small particles. As they oxidize they infiltrate the blood vessel wall and begin to get stuck. As they buildup they cause an inflammatory cascade. Immune cells called monocytes convert into macrophages and then into foam cells. These cells consume the oxidized LDL. They also send out molecules that attract other immune cells.(5) When doctors talk about plaque buildup in your arteries this is what they are talking about. This buildup is atherosclerosis. The oxidized LDL causes further destruction by decreasing the production of collagen and increasing its degradation.(6) Collagen is a protein that helps hold things together. But without it the plaque can rupture sending clots to the heart and brain causing heart attacks and strokes. The oxidized LDL also impairs cells from producing nitric oxide. Nitric oxide is a gas that helps with blood flow and decreases blood clotting and the adhesion of these immune cells.(7) So it is oxidized LDL that wreaks havoc injuring our cells and causing inflammation leading to atherosclerosis and its related complications.
What Can Be Done?
First of all stop consuming vegetable oils. Replace them with oils higher in saturated fat. That’s right, saturated fat. In fact there was a study comparing a diet of PUFAs versus a diet with a higher intake of saturated fat. The more PUFA consumed the worse the atherosclerosis became. The more saturated fat that was consumed, the less atherosclerosis progressed and in even reversed.(8) Saturated fat is very resistant to oxidation. Some good oils to use that are higher in saturated fat and great for cooking are coconut oil, avocado oil, palm oil and shortening, and my favorite, butter.
Exercise is another component. The more we exercise and move throughout the day the more efficient our blood flow becomes. When blood flow is can flow properly and less turbulent the less likely it is for plaques to form. Exercise also increases nitric oxide production which increases the size of the vessel and increases blood flow. And as mentioned earlier decreases the adhesion of immune cells to the blood vessel wall. It also prevents oxidation of LDL.
Proper nutrition is important. A nutrient dense diet will provide plenty of antioxidants such as Vitamin C, Vitamin E, and Coenzyme Q10, which is also produced from cholesterol. Sugar should be eliminated. Sugar increased inflammation adding to the problem. Carbohydrate consumption must be reduced. Our diets are typically filled with carbs. The ideal is to have 40% of our calories coming from carbohydrate sources. But this can differ from person to person. However, high quality carbohydrates should be chosen such as fruits and starchy vegetables like sweet potatoes. The other 60% will come from fats and protein. 40% will be from fats. Healthy fats include avocados, olive oil, coconut oil, butter from grass-fed cattle, and other pasture-raised/grass-fed animals. 20% should come from high quality protein sources. A nutrient dense diet gives the body the needed resources to repair, maintain, and build. This includes creating cholesterol.
We must remember that atherosclerosis increases with age. The problem today is that people are getting advanced atherosclerosis younger and younger. Also, we must understand that atherosclerosis is one type of arteriosclerosis. Arteriosclerosis is just one type of heart disease. There are many others. The recommendations above can help with many of them as well but it is not as simple as oxidized LDL causes all heart disease. And it is definitely incorrect to state eating saturated fats and high cholesterol foods will cause heart disease. Fats are an essential part of our diet without them and other vital nutrients we cannot make cholesterol which not only has vital role by itself, but also is the precursor to so many important substances we need. You can enjoy butter!