Lipids are molecules that contain hydrocarbons. They make up the building blocks of the structure as well as the function of living cells. Cholesterol is a type of lipid, in fact, cholesterol is part lipid and part protein. Some simplify the question by simply calling lipid a scientific term for “fat.” Many people know that cholesterol is not fat, but it does contain a waxy compound. Well, that waxy compound is really lipid. Cholesterol is in all our tissues and cells. The liver makes it and we get it from the food we eat.
Cholesterol is one of the important biological molecules, but there are other important lipids, including triglycerides. Both cholesterol and triglycerides travel through the bloodstream as lipoproteins. LDL and HDL are different varieties of lipoproteins.
Connection between cholesterol and lipid disorders
A lipid is a carbon-based molecule that doesn’t dissolve well in water. Most lipids do contain carbon and hydrogen, and some also include oxygen and phosphorus. Cholesterol consists mainly of carbon and hydrogen, but it does have some oxygen. In combination, carbon and hydrogen can decrease the ability of a compound to dissolve in water, while oxygen increases it. There is evidence suggesting that there is not enough oxygen in cholesterol to cause it to dissolve in water, thus answering the question, why is cholesterol considered a lipid?
Cholesterol is a component of cell membranes, brain and nerve cells, and bile, which helps the body absorb fats. The body uses cholesterol to make vitamin D and various hormones. Triglycerides, which are contained in fat cells, provide energy for growth. Cholesterol and triglycerides are packaged with proteins to form lipoproteins. There are low-density lipoproteins (LDL) and high-density lipoproteins (HDL). HDL is commonly referred to as the good cholesterol while LDL is bad cholesterol. Abnormal levels of cholesterol—for example, a high level of LDL or bad cholesterol—can lead to serious health problems, including atherosclerosis. Ultimately, this increases the risk of heart attack and stroke.
Use of drugs, a diet high in saturated fats, being overweight, or being sedentary could lead to an increase in lipid levels and bad cholesterol (LDL).
What is the role of lipids in the body?
The human body does need some lipids in order to maintain good health. Our bodies make cholesterol, which can help produce specific hormones, vitamin D, and enzymes to assist with digesting food. Cholesterol also comes from the foods we consume. Examples include egg yolks, dairy, red meat, and fish. If we have moderate levels of cholesterol in our body, it’s okay, although high levels can raise our risk of health problems.
It can help to understand the role of lipids in the body. For instance, lipids make up cell walls. Think of the body as having special entry and exit points to control the movement of compounds into cells. Research shows that cholesterol also plays an important role by aiding in digestion, manufacturing hormones, and protecting nerve endings.
When we look at the biological importance of lipids, it’s easy to see why our body depends on them.
- Fatty acid derivatives are used as an energy source
- Triglycerides are linked to a chemical called glycerol and are carried in the blood as complexes known as lipoproteins. They store energy for later use
- Phospholipids form part of the cell walls and help cells function
There are various lipoproteins that have an important job in our bodies. As an example, chylomicrons are a lipoprotein. They are large particles that carry dietary fats from the intestine through the circulatory system. Meanwhile, LDL delivers cholesterol to tissues where it’s used by growing cells that may be deposited when in excess. This might be where the term “bad cholesterol” came from. The main function of HDL is to remove cholesterol from cells and carry it back to the liver for excretion.
Low-density lipoproteins (LDL) vs. High-density lipoproteins (HDL)
While we have briefly introduced you to LDL and HDL, it is important to fully understand their differences. It is easy to get the two confused.
LDL is considered “bad” cholesterol because it has the ability to form waxy deposits in our arteries. The deposits, often referred to as plaque, make arteries stiffer. They can also clog arteries, leaving less room for blood to circulate. This is what is called atherosclerosis, or the hardening of the arteries. Plaques also run the risk of rupturing, which can spill cholesterol into the arteries. When this occurs, blood cells can rush to the site in an effort to form a blood clot. The problem is that if the blood clot is big, it can block blood flow, which in turn can cause a heart attack. When a clot blocks an artery in the brain or an artery carrying blood to the brain, it can lead to stroke.
HDL cholesterol, which is called “good” cholesterol, is supposed to sweep LDL out of our bloodstream and back to the liver. More cholesterol is produced in the liver and the process begins all over. HDL represents about one-fourth to one-third of cholesterol in the blood.
Lipids level limitation and recommendation
So, at this point, you likely have a better sense of what too much cholesterol or lipids really means. Naturally, we all want to avoid plaque and blood clots that can restrict blood flow and lead to heart attack or stroke. When a doctor tells you that you have too much cholesterol in your blood, they are referring to bad cholesterol and you should take it seriously. The USDA dietary guidelines set out specific recommendations for cholesterol intake. The guidelines stipulate that Americans should have less than 300 mg per day of dietary cholesterol. In order to reduce lipids in the diet, you have to reduce total fat, saturated fat, and cholesterol. To give you a sense of cholesterol levels in food, an egg generally contains over 200 mg of cholesterol in the yolk alone.
Measuring lipid levels
HDL and LDL can be measured through a simple blood test. The results are usually determined in milligrams per deciliter (mg/dL). Normal LDL is around 10 mg/dL and normal HDL is about 40 mg/dL. An important lipid measurement, called “total cholesterol” is simply a calculation that adds your LDL and HDL levels and 20 percent of your triglycerides. Total cholesterol may be able to help your doctor determine what your risk of future heart attack is.
Unless your doctor suggests annual check-ups, it is a good idea to have cholesterol levels checked every few years. It is worth noting that as we age, our LDL level tends to rise.
Treating dyslipidemia
Dyslipidemia is an abnormal level of lipids in the blood. It is a serious risk factor for heart disease. The good news is that it is treatable for most people. Some individuals with high LDL levels keep these levels within a healthy range using medication.
Statins are one of the most commonly prescribed medications to control cholesterol. There are several different types and a qualified doctor can determine what is best in each case. These drugs or other cholesterol-lowering medications may have to be adjusted from time-to-time, but it is important to not stop taking them unless advised to do so by a doctor. Other medications, including fibrates, niacin, PCSK9 inhibitors, and bile acid binding resins may be prescribed. Leading a healthy lifestyle and controlling cholesterol with a well-balanced diet that is low in fats is also achievable.
Tips for managing cholesterol
If you are concerned about cholesterol or know someone who is struggling with high cholesterol, think about the following tips:
Diet: Eat a diet low in cholesterol and saturated fats. Consider working with a dietitian to develop a healthy eating plan.
Exercise: Participate in at least 150 minutes of moderate-intensity exercise every week as recommended by the American Heart Association. This could include, brisk walking.
Regular check-ups: See your doctor for check-ups and regular blood work so your lipid levels can be closely monitored.
People who have heart attack risk factors like high blood pressure, a history of smoking, or a history of heart disease in the family should have their cholesterol checked yearly. If you fall into this category, you will also want to avoid foods that can raise cholesterol levels. For instance, fast foods, baked goods, cream cheeses, red meats, and snack foods with a lot of salt should be eliminated or reserved for special occasions only. It is also important to keep in mind that multiple studies show that people who exercise and control their diet improve their heart risk profile.
Related: Why cholesterol is actually good for you