The human body is efficient in that it regularly creates many of the substances it needs to be healthy and to function properly. These substances include hormones, chemicals, vitamins and even cholesterol. These days, the word cholesterol carries with it a negative connotation due to “bad” cholesterol being one of the primary causes of cardiac and vascular disease. In general, “good” cholesterol and the vital roles that it plays within the body are often overlooked. So, what exactly is cholesterol - good and bad, how does it help us, and how does it cause disease? What preventive steps can we take to reduce our chances of developing a life-threatening disease caused by hypercholesterolemia? In this article, we will explore these answers and offer helpful tips and information regarding this subject.
What is Cholesterol?
Cholesterol is a waxy, oil-based substance that is found not only in the blood but also in all cells of the body. This substance, produced by the body, is not actually a fat, it is a sterol. A sterol is a naturally occurring group of solid, unsaturated alcohols found in plants and animals; the body cannot draw any energy from it because it contains no calories. This leads us to the question of if cholesterol is not a fat, how does it become detrimental to our health? The answer to this question is due to the difference between high-density lipoproteins (HDL) and low-density lipoproteins (LDL), which we will discuss shortly.
Where is it produced?
The human body creates a majority of the cholesterol that it requires; it produces roughly 80% while the remaining 20% is derived from a person’s diet. Cholesterol is primarily synthesized by the liver with about 20% of production occurring there. Other sites of synthesis include the reproductive glands, intestines and adrenal glands. Because the body monitors its own cholesterol levels, it will produce more if cells do not have enough. Dietary cholesterol is acquired through eating and is found in foods such as dairy products, red meat, poultry, pork, shellfish, eggs, and cheese.
What are the main roles of cholesterol in the body?
There are five vital functions:
- Aids in the production of Vitamin D which is essential for strong bones and healthy teeth. Vitamin D is responsible for maintaining normal levels of calcium and phosphorus.
- Assists in producing bile acids that aid in the digestion of fats ingested through eating.
- Facilitates the production of hormones, especially steroid hormones produced by the adrenal and sex glands. These include testosterone, progesterone, estradiol, aldosterone, corticosterone, and others.
- It is an essential structural component as it aids in the production, support, and protection of cell membranes.
- It is vital for neurological function and brain development as it allows neurons to communicate with each other and exchange electrical signals within the central nervous system. The brain is the most cholesterol-rich organ in the body with up to 25% of the body’s total cholesterol being found here.
The Difference Between HDL and LDL
Because cholesterol is oil-based and does not mix with blood which is water-based, it is carried around the body by lipoproteins. Lipoproteins are quite literally fat(lipids)+soluble proteins with proteins on the outside and lipids on the inside. There are two types of lipoproteins, LDL and HDL. Low-density lipoproteins (LDL) are frequently referred to as the "bad" type of cholesterol. LDL circulates in your blood and leaves fatty deposits which result in a buildup of plaque within the lining of your arteries. High-density lipoproteins (HDL) are viewed as the "good" type of cholesterol. HDL aids in keeping bad cholesterol away from your arteries by clearing away excess LDL found in the blood and then transporting it back to the liver. Once LDL is in the liver, it is removed by utilizing it for the production of bile acids which aid the intestines in the digestive process. Because HDL can assist with clearing away excess fatty deposits in the arteries, it is helpful in the prevention of cardiovascular disease.
What levels are considered normal by healthcare providers?
Every adult should have their cholesterol checked at least once every five years as part of their yearly physical exam. How this is done is through a blood test called a lipid profile which measures a person’s total cholesterol along with individual LDL and HDL levels. A total cholesterol level is inclusive of both LDL and HDL levels. This test will help a physician determine a person’s level of cardiac risk, along with any other known risk factors for heart disease. The results of this test will also assist the physician in developing a plan of treatment and follow-up if needed.
The following table shows what the optimal, borderline and high cholesterol numbers are per healthcare industry standards. Do you know your numbers?
|Total Cholesterol||200mg/dL or less||200-239mg/dL||240mg/dL or higher|
|LDL - Bad cholesterol||Less than 100mg/dL||130-159mg/dL||160mg/dL and above|
|HDL - Good cholesterol||60mg/dL or higher - protective against cardiovascular disease||40-59mg/dL||Less than 40mg/dL - major risk factor for cardiovascular disease|
Hypercholesterolemia and Atherosclerosis
When a person’s total cholesterol or LDL numbers are too high, they have what is called hypercholesterolemia. Hypercholesterolemia is a condition that can result in serious health conditions such as coronary artery disease, peripheral artery disease, and cerebrovascular disease. The higher the LDL level is, the greater the risk. Inversely, the higher the HDL level, the lower the risk of developing cardiovascular disease.
One major complication of hypercholesterolemia is a condition known as atherosclerosis. Atherosclerosis, or the hardening and narrowing of the arteries, is caused by the buildup of cholesterol plaques along the inner lining (endothelium) of the arterial walls. These plaques are usually able to form and adhere to the vessel wall after damage to the endothelium has occurred by other factors that include smoking, high blood pressure, diabetes, and more. When LDL attaches to the arterial wall it causes inflammation; in response, the body will send white blood cells (macrophages) to attack the cholesterol. Over a period of time the combination and accumulation of cholesterol and white blood cells (both active and dead), along with calcium and other crystallized materials, will build up and create atherosclerotic plaque. This buildup of plaque can significantly reduce blood flow causing some disease states.
Three common conditions caused by atherosclerosis
Atherosclerosis is a chronic, cumulative and slowly progressive condition that may remain asymptomatic for many years. Once atherosclerotic plaque has significantly reduced blood flow within an artery it can wreak major havoc on the body, depending on its location. There are three common conditions caused by atherosclerosis:
- Coronary artery disease- This is the most common form of heart disease. It is characterized by plaque buildup in the arteries that supply blood to the heart and limits the flow of oxygenated blood to the heart tissue. Myocardial ischemia is the lack of oxygenated blood flow to the heart which can result in cardiac tissue damage; it is the major cause of angina and most heart attacks. Once the tissue is damaged, the heart’s ability to pump efficiently is severely reduced and can cause serious dysrhythmias. Angina is severe pain in the chest that can also spread to the shoulders, arms, or neck.
- Cerebrovascular disease - This disease is characterized by decreased or complete obstruction of oxygenated blood flow to the brain. Commonly, soft plaque will suddenly break away from an arterial wall causing the formation of a thrombus (blood clot) that travels to the brain. This thrombus will rapidly slow or obstruct blood flow causing a cerebrovascular accident (CVA), commonly known as a stroke. Just like with coronary artery disease, ischemia can occur and can result in brain injury or death. A transient ischemic attack (TIA), often called a mini-stroke, is the result of a temporary blockage in the arteries of the brain and usually only lasts for a short period of time. TIAs are indicative of an impending major stroke if left untreated.
Peripheral artery disease - This disease is characterized by atherosclerotic plaque buildup that decreases or stops the flow of blood within the arteries of the arms and legs; it also affects the arteries that carry blood to and from the stomach and kidneys. Significantly decreased or obstructed blood flow to the arms and legs can cause cramping, pain, and numbness. If the artery is severely blocked, usually due to a thrombus, it can cause gangrene (tissue death). In some cases of severe gangrene, amputation is necessary.
An additional complication of cardiovascular disease is the potential development of an aneurysm. An aneurysm is a localized bulge caused by the weakening of an arterial wall; it can occur anywhere in the body. If an aneurysm ruptures, it can cause a life-threatening emergency due to internal bleeding.
Symptoms and Risk Factors
Hypercholesterolemia by itself is usually asymptomatic, meaning that it does not present any signs or symptoms. Often it is not until an adverse event occurs, such as the threat of a heart attack or stroke, that testing is done to confirm this condition. Routine lipid profiles should be conducted for those who are considered to be at a higher risk. Various factors, both modifiable and non-modifiable, determine who is at the highest risk of developing high cholesterol and cardiovascular disease.
Non-modifiable risk factors tend to be genetic and include:
- Sex - Men ages 45 years or older, and women after menopause
- Genetic abnormalities such as familial hypercholesterolemia
- Family history of heart attack or stroke
Modifiable risk factors include:
- High blood pressure (hypertension)
- Sedentary lifestyle
- Eating a diet high in saturated fats and trans fats
Prevention of high cholesterol
Reducing the chances of developing a condition associated with high cholesterol begins with each individual. Obviously, some factors are out of a person’s control, but every step that is taken to lower LDL levels will assist in slowing or stopping the process of plaque formation. Living a healthy lifestyle will not remove plaque or blockages that have already formed, but it can prevent further progression. Most people can lower their cholesterol levels by:
- Exercising regularly - Exercise not only helps people to lose weight, but it also raises HDL levels while lowering their LDL. Aim to engage in at least 30 minutes of exercise per day.
- Limiting alcohol intake - According to the CDC, “Men should have no more than 2 drinks per day, and women only 1.”
- Losing weight or maintaining a healthy weight - Excess weight contributes to a high LDL level. Losing as little as 5-10 pounds can help to lower bad cholesterol levels.
- For those who smoke - Quitting will lower the risk of developing heart disease as smoking damages blood vessels and speeds up the hardening of the arteries.
- Eating a well-balanced diet - Choosing healthy options such as fruits, whole grains and vegetables will help in avoiding bad cholesterol. Limit the amount of saturated fats that are found in red meat, processed meats, and dairy products. Avoid trans fats which are commonly found in processed foods.
5 superfoods that are great for your heart:
- Salmon - This fish contains a lot of omega-3 fatty acids which aid in lowering the risk of atherosclerosis and arrhythmias. The American Heart Association recommends eating fish at least twice a week.
- Tomatoes - This vegetable is a good source of the antioxidant lycopene and heart-healthy potassium. It is believed that lycopene helps to reduce inflammation and cholesterol which can help to decrease the incidence of heart attack or stroke.
- Oatmeal - Helps to reduce cholesterol levels because it is high in soluble fiber. Fiber acts like a sponge in the intestines during digestion and soaks up cholesterol before it is absorbed into the bloodstream.
- Nuts - Almonds, macadamia nuts, pistachios, walnuts, and peanuts all contain vitamin E which helps to lower cholesterol. They also contain fiber and omega-3 fatty acids. Make sure to choose low salt options.
- Dark green vegetables - Vegetables such as spinach, kale, and broccoli are high in fiber and act as antioxidants in the body. They also contain iron, calcium, folate, and vitamins C and K.
- Bake, boil or grill instead of frying. Use a baking or broiling rack to help drain fats from meats cooked in the oven.
- Select lean cuts of meat. Trim the fat from meats and remove the skin from poultry prior to cooking or eating.
- Choose white meat poultry. Dark meats are higher in fat.
- Use canola, olive, sunflower or safflower oil instead of shortening, butter, or lard. Coconut oil is also a good substitute.
- Cook fresh vegetables in a tiny amount of oil and water. Place in a pan and cover; cook on low heat. Add herbs and spices to taste.
- For baking recipes that require a specified amount of oil, you can substitute it with the same amount of unsweetened applesauce.
Common Medications Prescribed for High Cholesterol
Maintaining a healthy lifestyle, eating a healthy diet and regularly exercising is sometimes not enough for some individuals. For those who find themselves in this situation, cholesterol-lowering medications may help. After a full assessment by a licensed physician, they may prescribe a single drug or a combination of drugs to lower LDL and increase HDL. Most often, the first type of drug a physician will prescribe is called a statin; statins lower LDL and triglycerides, a different type of blood fat. This kind of drug is also helpful in the prevention of heart attacks by increasing the stability of the blood plaque to the scarred tissue thanks to balancing done to the amount of cholesterol and scar tissue.
Commonly prescribed statins include:
The following are other types of drugs commonly prescribed:
|Type of Drug||Name of Drug||Used For|
|Prescription B vitamin||Niacin||Decreasing LDL and increasing HDL|
|Combination statin and niacin||Niacin-lovastatin||Lowering LDL and increasing HDL|
|Cholesterol absorption inhibitor||Ezetimibe||Decreasing LDL and slightly increasing HDL|
|Bile acid binding resins||Cholestyramine, colestipol, colesevelam||Decreasing LDL|
Common Procedures Performed on Narrowed or Blocked Arteries
Because atherosclerosis by itself is usually asymptomatic, some individuals may not know they have cardiovascular disease until an adverse event occurs. These events can range anywhere from angina to a major heart attack or stroke. When this happens, a physician will perform a series of tests to determine the location and severity of the blockage. Depending on these results, different procedures can be conducted to unblock the affected arteries.
The following is a simple list of procedures that are commonly performed:
- Angioplasty - A balloon on the end of a cardiac catheter is used to widen and increase blood flow through a blocked or narrowed artery. It reduces angina and risk of heart attack. This procedure can also be used to unblock arteries in the neck, brain, and extremities.
- Laser Angioplasty - Increases blood flow through blocked or narrowed arteries using pulsating beams of light to obliterate plaque buildup.
- Atherectomy - Similar to angioplasty except plaque is shaved away with a rotating shaver on the end of a cardiac catheter. Can also be used for unblocking carotid arteries.
- Stent Procedure - A wire mesh tube is inserted into an artery to hold it open which improves blood flow to the heart or extremities depending on the artery’s location and extent of the blockage. A stent placement is permanent.
- Carotid Endarterectomy - This procedure involves making a surgical incision in the neck and then removing plaque from narrowed carotid arteries which restore blood supply to the brain to reduce the risk of stroke.
According to the World Health Organization, 17.5 million people die each year as a result of cardiovascular diseases which are an estimated 31% of all deaths worldwide. 80% of these deaths are due to heart attack and stroke. With these statistics, prevention of high cholesterol and cardiovascular disease should be a priority for every individual.
See also our Guide to a Healthy Heart for more advice on heart health.
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