Cholesterol
Overview
Cholesterol is a steroid-class lipid that is a major component of animal cell membranes and serves as a precursor for the synthesis of hormones, vitamin D, and bile acids. It is synthesized in the liver or obtained from food, and is transported in the blood by lipoproteins. Elevated cholesterol levels are a major risk factor for cardiovascular diseases such as atherosclerosis, myocardial infarction, and stroke, but excessively low levels can also cause hormonal imbalances or cellular dysfunction, making it important to maintain appropriate levels.
Main Content
1. Types and Functions of Cholesterol
Cholesterol is broadly divided into low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol. LDL is called 'bad cholesterol' and accumulates on blood vessel walls, forming atherosclerotic plaques that narrow and block vessels. In contrast, HDL is 'good cholesterol' and transports cholesterol from peripheral tissues to the liver for excretion. Triglycerides are also part of the lipid profile, and hypertriglyceridemia increases the risk of pancreatitis and cardiovascular disease.
2. Normal Levels and Dyslipidemia
Generally, total cholesterol below 200 mg/dL is desirable, with LDL below 100 mg/dL and HDL above 60 mg/dL considered ideal. Triglycerides are recommended to be below 150 mg/dL. Dyslipidemia is a condition of high LDL or triglycerides or low HDL, caused by genetic factors (familial hypercholesterolemia), dietary habits (excessive intake of saturated and trans fats), obesity, diabetes, hypothyroidism, etc.
3. Role of Diet and Lifestyle
The impact of dietary cholesterol (e.g., eggs, shrimp) on blood cholesterol varies greatly among individuals, with saturated and trans fats having a greater effect. The Mediterranean diet (olive oil, nuts, fish, vegetables) is effective in raising HDL and lowering LDL. Regular aerobic exercise, smoking cessation, moderate alcohol consumption, and weight loss also help improve the lipid profile.
4. Drug Treatment
When lifestyle modifications alone are insufficient, statin-class drugs are used as first-line therapy. Statins inhibit HMG-CoA reductase, reducing cholesterol synthesis in the liver and increasing LDL receptor expression. Ezetimibe, PCSK9 inhibitors, fibrates, and omega-3 fatty acid preparations are used as combination or alternative therapies. Treatment goals are set differentially based on the patient's cardiovascular risk (diabetes, hypertension, smoking, family history, etc.).
5. Complications and Prevention
If hypercholesterolemia persists long-term, atherosclerosis progresses, potentially leading to angina, myocardial infarction, cerebral infarction, and peripheral vascular disease. To prevent acute cardiovascular events, lipid testing is recommended for adults aged 20 and older at least every 4–6 years, with more frequent testing for those with risk factors. Early detection and active management are crucial.
Recent Trends
As of 2024–2025, the paradigm of cholesterol management is shifting, with measurements of 'LDL particle number (LDL-P)' or 'apolipoprotein B (apoB)' gaining attention as more accurate predictors of cardiovascular risk than 'LDL levels themselves.' Additionally, genetically elevated lipoprotein(a) [Lp(a)] is recognized as an independent risk factor, spurring active drug development. Oral formulations of PCSK9 inhibitors are in clinical trials, and the siRNA-based inclisiran has been approved as an innovative treatment that lowers LDL by over 50% with twice-yearly administration. Dietary guidelines have relaxed restrictions on cholesterol intake, but limits on saturated fats and processed foods remain emphasized. AI-based personalized lipid management apps and continuous blood lipid monitoring technology via wearable devices are also under research.
Related Topics
- [[Atherosclerosis]]
- [[Cardiovascular disease]]
- [[Statin]]
- [[Lipoprotein]]
- [[Dyslipidemia]]
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