Cholesterol – it’s a very dirty, scary word in our culture. Why? Because so many people die every year from heart disease, which is largely blamed on dietary fat and cholesterol. But there are quite a few misunderstandings about cholesterol and its role in health and disease. In this article I’m going to explain why we need cholesterol for health, why dietary cholesterol isn’t harmful, and why, if these things are true, high cholesterol is often associated with heart disease.
First of all, cholesterol is essential for optimum health and has numerous functions in the body. Over 35,000 mg of cholesterol can be found in the average human body at any give time. Most of that amount is found in the cell membranes, where it serves as an important structural component. Cells need cholesterol to maintain the permeability that allows nutrients to nourish the cells. Cholesterol is also the structural precursor for steroid hormones, such as testosterone, estrogen, and cortisol, all of which are crucial for proper metabolism and reproductive health. Additionally, cholesterol is needed in order to produce one of the body’s most important vitamins, vitamin D. Then there’s bile production (bile is essential for the digestion of fats) — it too depends on cholesterol. The immune system is also strengthened by cholesterol. And, finally, cholesterol is an essential component of myelin, which forms the protective sheaths around neurons, allowing the central nervous system to function properly! Moral of the story: we need cholesterol!
If cholesterol has so many health benefits, then why is it associated with cardiovascular disease? Well, a growing body of evidence is starting to reveal the answer. Initially researchers noticed a correlation between cholesterol levels, especially high LDL cholesterol, and incidence of heart disease. Then, as is so often the case in the realm of medicine, dietary cholesterol was demonized without an understanding of all the other factors at play. We now know that dietary cholesterol actually has a very minimal effect on blood cholesterol levels, if any, and that saturated fats, in and of themselves, don’t cause elevated cholesterol levels either. In fact, the body is highly efficient at maintaining cholesterol levels and will actually decrease it’s own production of cholesterol when cholesterol is obtained from diet.
While LDL undoubtedly has a role in atherosclerosis, few people seem to known what LDL is or that there are actually different types of LDL. Not all LDL is created equal. In a nutshell, LDL (Low Density Lipoprotein) is basically a protein shuttle that carries cholesterol to the cells. The cells then use the cholesterol to repair the themselves or produce hormones. LDL levels are known to rise as a result of mental stress (stress drains the body of stress hormones that are cholesterol-based), physical injury, smoking (which causes injury to the cells), and overeating. LDL levels can also be elevated as a result of a genetic predisposition to having fewer LDL receptors. If there aren’t enough receptors on the cells, then the LDL continues circulating in the blood stream where it can eventually lodge into the arteries and promote arterial plaque.
It’s important to reiterate that LDL, in and of itself, isn’t unhealthy. In a way, a high ratio of LDL to HDL is merely a sign that the body is undergoing some form of stress that needs to be remedied. Targeting LDL is kind of like removing the warning signal instead of fixing the actual problem. LDL is important because it provides nourishment to the cells, but there are two factors that can make LDL particularly problematic: particle size and oxidation.
A high carbohydrate diet, particularly one that’s high in fructose and refined sugar, can caused the body to produce a certain type of LDL called Small Dense LDL. These LDL particles are smaller and denser than they should be, which makes them more prone to lodging themselves in artery cell walls and initiating the first stages of atherosclerosis and heart disease. A whole-food based diet, however, that’s higher in healthy fats, causes the body to produce larger, fluffier LDL particles that don’t damage the arteries as easily.
Perhaps even more dangerous than Small Dense LDL particles are oxidized LDL particles. Several recent studies have found a direct correlation between the amount of LDL oxidation in circulation and an increased risk for cardiovascular disease. Oxidized LDL is basically a damaged, unstable LDL molecule that is absorbed by the arteries’ immune cells in self-defense. When oxidized LDL is absorbed by these cells (called macrophages) foam cells can form that bulge and lead to atherosclerosis.
So what causes oxidized LDL? There are several potential culprits, for one, a diet high in polyunsaturated fats (PUFAs). PUFAs (found in refined seed oils like corn, canola, and soybean oil) are unstable and prone to damage. When these types of fats are digested, they’re used for building LDL particles; in turn, these LDL particles are prone to oxidation. Saturated and monounsaturated fats, by contrast, (butter and olive oil) are much less prone to oxidation and, therefore, result in LDL that is resistant to oxidation.
Inadequate supplies of antioxidants, especially Co-enzyme Q10 and vitamin E, can also lead to excess oxidized LDL. Coenzyme q10 is specially manufactured by the body to protect LDL and HDL cholesterol from damage, but in order to produce it, the body needs plenty of b-vitamins. Coenzyme q10 can also be obtained from grass-fed beef (especially the liver) and from dietary supplements. Studies indicate that supplemental co-enzyme q-10 does have a cardioprotective role and can protect LDL from oxidation. Vitamin E is another important fat-soluble antioxidant for protecting lipoproteins, but it works best in the presences of co-enzyme q-10. There are also a number of polyphenols from plants that have the ability to protect against oxidation, as well as increase the number of LDL receptors (which means there are more “nets” to remove LDL from the blood stream). Some of these polyphenols include EGCG from green tea, resveratrol from red wine, and quercetin, which is found in onions, apples, and berries.
The Take Away: Our bodies absolutely depend on cholesterol for health. While, in certain cases, cholesterol can contribute to heart disease, dietary cholesterol isn’t the problem. The quality of cholesterol the body produces is more relevant than the quantity. Healthy cholesterol depends on eating the right kinds of oils (monounsaturated and saturated fats found in natural products like butter, olive oil, and coconut oil), grass-fed meats, and plenty of leafy greens that are high in fat-soluble anti-oxidants. High LDL levels may require a dietary and/or lifestyle change, including stress reduction. Some people are also genetically predisposed to having higher LDL levels, in which case it’s especially important to prevent LDL particles from becoming oxidized by eating a nature-based diet.
References: Dietary Cholesterol Reduces Endogenous Production, The Role of Oxidized LDL in Atherosclerosis, Is Dietary Cholesterol as Bad for You as History Leads us to Believe?, Regulation of LDL by Carbohydrates, Small Dense LDL and Atherosclerosis, Association of Circulating Oxidized LDL with Heart Disease, Effects of Co-enzyme q10 on Oxidized LDL in Vitro, Cardioprotective Effects of Dietary Polyphenols, Consumption of Fructose and HFCS Increase LDL, Green Tea Upregulates LDL Receptors
Originally posted 2013-06-04 17:33:00.