[Kim Jaeho's Life Story]<229> The Value of Faded Cholesterol

Nowadays, as health checkups have become widespread, cholesterol levels are among the frequently pointed out items. In health checkups, the results of hyperlipidemia tests generally report low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, and the total cholesterol level, which is the sum of these. What exactly is cholesterol that it is tested as a major item every time during health checkups, and why do doctors prescribe medication if the test results show high levels?

Cholesterol is a type of lipid, a broader category than fat, and plays an important role in our body. It is a component of the cell membrane of all cells, providing strength and flexibility to the membrane. It is produced in the liver and also serves as a raw material for bile acids that aid fat digestion, vitamin D, and hormones such as estrogen. Although cholesterol is such an essential substance, it attracts attention because excessive amounts can cause serious problems.

Cholesterol is produced in the liver, but some is also ingested through food. Foods high in cholesterol include egg yolks, meat, cheese, and shellfish. There is no need to deliberately consume these foods to intake cholesterol, nor is there a strong reason to avoid them. According to research, about 25% of the cholesterol needed by the body comes from food intake, while the rest is produced by the liver.

Because cholesterol does not dissolve in water, it must bind to proteins to be transported throughout the body via the blood. This complex of cholesterol and protein is called lipoprotein. Depending on the relative density of cholesterol and protein, lipoproteins are classified into high-density lipoprotein, low-density lipoprotein, and very low-density lipoprotein, each having different roles and health impacts.

Low-density lipoprotein, commonly known as "bad cholesterol," mainly transports cholesterol throughout the body, but excessive amounts cause many health problems. High-density lipoprotein, known as "good cholesterol," returns used cholesterol to the liver for breakdown, and having more of it is beneficial for health. Very low-density lipoprotein primarily transports triglycerides.

Although cholesterol plays an important role in our body, excessive amounts cause serious health issues. What we need to be cautious about is when cholesterol levels rise excessively, with low-density lipoprotein (LDL) at the center of concern. When LDL levels become too high, it signals a health warning.

If there is too much LDL in the blood, these particles accumulate on the walls of arteries, narrowing or blocking them; this buildup is called plaque. When plaques increase, they can rupture and form blood clots (thrombi), a condition known as atherosclerosis. As atherosclerosis progresses, it can develop into serious vascular diseases such as angina, myocardial infarction, and stroke. This means LDL lies at the root of vascular diseases that threaten our lives second only to cancer.

What causes an increase in LDL, the low-density lipoprotein? Cholesterol is produced and broken down in the liver. Earlier, it was mentioned that eating foods high in cholesterol is not a big problem because the liver adjusts the total cholesterol amount to an appropriate level. So, what disables the liver's cholesterol regulation ability? Let's examine how the liver regulates cholesterol.

Liver cells have LDL receptors on their surface. When LDL passes through the blood and its level is high, these receptors bring LDL into the liver to break it down, lowering cholesterol levels to maintain an appropriate balance. However, excessive intake of saturated fats weakens the function of these LDL receptors, causing them to malfunction. This is why consuming a lot of saturated or trans fats increases cholesterol in the blood.

Causes of elevated LDL include unhealthy dietary habits with high intake of bad fats such as saturated fats and trans fats (refer to Life Story episodes 18 and 19), lack of physical activity, unhealthy lifestyle habits like smoking, and obesity.

To maintain cholesterol at an appropriate level and prevent vascular diseases, it is essential to improve the unhealthy lifestyle habits described above. If you are taking medication to improve hyperlipidemia, always remember that medication is only a temporary measure, and you must also make efforts to correct the lifestyle habits that raise cholesterol levels.

In terms of diet, reduce intake of most animal fats, including meat high in saturated fats, dairy products such as cheese and butter, and some plant fats like coconut oil and palm oil. Avoid margarine, shortening, and fried fast foods that contain high amounts of trans fats.

Kim Jae-ho, Independent Researcher

This content was produced with the assistance of AI translation services.