Doug Ross

Cholesterol: Friend Or Foe?

Exploring the science behind the controversial role of cholesterol in the human body.

cholesterol bad and good egg

Cholesterol has been at the centre of debates among medical professionals and researchers for years. Although it’s essential for many bodily functions, high levels of cholesterol in the bloodstream can also lead to serious health problems. Therefore, a lot of the attention surrounding the effects of cholesterol focuses on the balance between the ‘good’ and the ‘bad.’ Let’s explore these factors so we can gain a better understanding of this balance and, as a result, make more informed decisions about our diet and lifestyle.

What is cholesterol?

Cholesterol is a type of lipid, or fat, produced by the liver. Dietary cholesterol, another form, can be found in certain foods, including meat, eggs, and dairy products. As a component of cell membranes, cholesterol plays a role in maintaining cell structure and integrity. In addition, it assists in the synthesis of hormones including estrogen, testosterone, and cortisol, as well as the digestion and absorption of dietary fats.

As cholesterol doesn’t dissolve in water, it can’t travel through the blood on its own. Therefore, cholesterol is transported throughout the human body by lipoproteins, which are made up of both proteins and lipids and are also produced by the liver.

‘Good’ and ‘bad’ types of cholesterol

These lipoproteins come in a variety of sizes and densities, depending on their composition. Lipoproteins with a higher protein content and a lower lipid content are smaller and denser than those with more lipids and fewer proteins.

The two types of lipoproteins that are commonly measured in cholesterol tests are high-density lipoprotein (HDL) and low-density lipoprotein (LDL).

Lipoproteins containing a high proportion of proteins and a low proportion of lipids, e.g., HDL, are known as ‘good’ cholesterol because they assist in the removal of excess cholesterol from the bloodstream and transport it to the liver for processing.

In contrast, lipoproteins containing a high proportion of lipids, e.g., LDL, are also called ‘bad’ cholesterol due to the fact that they can contribute to the formation of plaque in the arteries.


The benefits of HDLs

HDLs play a critical role in the body’s cholesterol metabolism and have numerous potential benefits.

1Reduces the risk of cardiovascular problems

The liver and small intestine produce HDLs, which are then released into the bloodstream and used to remove extra cholesterol from the body’s cells and tissues.

This excess cholesterol is transported back into the liver, where it is processed and excreted from the body. As a result, HDLs help to prevent the buildup of excess cholesterol in the bloodstream, thus reducing the risk of developing health problems such as atherosclerosis and heart disease.

2May have an anti-inflammatory effect

What’s more, HDLs possess anti-inflammatory properties, providing further benefits for cardiovascular health.

3Protecting cells against oxidative damage

In addition, they also contain enzymes and proteins that help protect cells against oxidative damage, in which free radicals impair cellular function.

The disadvantages of LDLs

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Although LDLs play a crucial role in cholesterol metabolism, excess levels of LDLs can increase the risk of diseases.

Increases the risk of atherosclerosis and heart diseases

LDLs are synthesized in the liver and small intestine and play the role of transporting cholesterol to the body’s cells and tissues. However, when LDL levels become too high, excess cholesterol accumulates in the blood, leading to the development of atherosclerosis and other health issues linked to high cholesterol. This is because cholesterol joins with other substances such as fatty deposits and calcium to form a thick, hard deposit on the inner walls of arteries.

Unfortunately, over time, this buildup forms plaques, narrowing the arteries and making them less flexible, thus restricting blood flow and increasing the risk of cardiovascular problems such as heart attack and stroke.

Contribute to inflammation and oxidative stress

LDLs can also increase inflammation and oxidative stress, both of which are known to play a role in the risk and development of cardiovascular disease.

Tips on maintaining healthy cholesterol levels

Reducing LDL levels is essential for keeping cholesterol levels under control and reducing the risk of atherosclerosis. Fortunately, there are a few ways to do that; here are a few of our favorites.

1Exercise, exercise, exercise

Not only does exercise improve physical fitness, but it also reduces LDL and increases HDL levels. Moreover, even low-intensity exercise such as walking can increase HDL levels, with longer and more intense training increasing this benefit.

2Choose unsaturated fats

Research indicates that a diet high in monounsaturated fats, most notably the Mediterranean diet, helps reduce levels of LDL and increase levels of HDL. Foods rich in monounsaturated fats include: olive oil, nuts, and avocados.

3Get your weight under control


Losing excess body weight can help lower cholesterol and LDL cholesterol levels, as well as triglycerides. In a study, participants who lost 5–10% of their total body weight reduced cholesterol and triglyceride levels significantly.

4Reduce alcohol intake and smoking

The American Heart Association suggests drinking alcohol in moderation (less than two drinks per day for men and less than one drink per day for women). Excess alcohol intake can raise levels of fat in the blood, leading to conditions such as hypertension and atrial fibrillation. In addition, smoking decreases HDL levels.

5Cut down on red and processed meats

Red and processed meats are high in saturated and trans fats, which increase LDL levels, thus increasing the risk of heart disease. These types of foods also tend to be high in sodium, which is a risk factor for heart disease as it increases blood pressure.

Interesting & curious facts about cholesterol

  • The word ‘cholesterol’ comes from the Greek words ‘chole’ and ‘sterol’, meaning ‘bile’ and ‘solid’, respectively. This is because early researchers discovered cholesterol in the solid form of gallstones.

  • Familial hypercholesterolemia is a condition that causes extremely high levels of LDL cholesterol at birth and affects about 1 in 250 people worldwide.

  • Women tend to have higher levels of HDL cholesterol than men, which might partially explain why women are generally at lower risk of heart disease than men.

  • Cholesterol levels can vary depending on the time of day. Studies have shown that cholesterol levels are highest in the morning and lowest in the evening.

So, is cholesterol a friend or foe?

Cholesterol is, in fact, essential for many bodily functions; however, high levels of cholesterol in the bloodstream may cause serious health problems. Therefore, it’s vital to incorporate lifestyle habits such as regular exercise and eating a diet low in saturated and trans fats. By making informed decisions, the risk of cardiovascular disease and other cholesterol-related diseases will be reduced.

Want to learn more about cholesterol?

Here’s a video of Dr. Peter Attia and Dr. Andrew Huberman discussing the relationship between dietary cholesterol and health.

Healthypedia FAQ

While low cholesterol levels are generally not a concern, excessively low levels may be associated with an increased risk of certain health problems such as depression, anxiety, and hemorrhagic stroke.

VLDL stands for very-low-density lipoprotein. It’s a type of lipoprotein produced by the liver, that is responsible for transporting triglycerides.

The American Heart Association recommends that total cholesterol levels be less than 200 mg/dL, LDL cholesterol levels be less than 100 mg/dL, and HDL cholesterol levels be greater than 60 mg/dL.

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