Lipids are a general term for the neutral fats (triglycerides and cholesterol) and lipids (phospholipids, glycolipids, sterols, steroids) in blood plasma, which are widely present in the human body. They are essential for the basic metabolism of living cells. Generally speaking, the main components of lipids are triglycerides and cholesterol, of which triglycerides are involved in energy metabolism in the body, while cholesterol is mainly used for the synthesis of cell plasma membranes, steroid hormones and bile acids.
Although plasma lipid content only accounts for a very small portion of the total lipid content in the body, both exogenous and endogenous lipid substances need to be transported into the blood to run between tissues. Therefore, blood lipid levels can reflect the lipid metabolism in the body. After consuming a high-fat meal, the plasma lipid level increases substantially, but this is temporary and usually normalizes gradually after 3-6 hours. When testing fixed lipids, blood is often taken 12-14 hours after a meal so that it can more reliably reflect the real situation of lipid levels. Because elevated plasma cholesterol and triglyceride levels are associated with the development of atherosclerosis, these two items have become the focus of lipid measurements.
Short-term starvation can also cause a temporary increase in blood lipid levels due to the massive mobilization of stored fat. It is easy to understand why when you go to the hospital to have your blood lipids checked, your doctor asks you to fast for 12 hours after you have eaten dinner and not eat anything else.
Hyperlipidemia is an elevated level of cholesterol or triglycerides in the blood plasma. It is a relatively common disease, except for a few due to systemic diseases (secondary hyperlipidemia), the vast majority are caused by genetic defects (or interaction with environmental factors) (primary hyperlipidemia).
Five major misconceptions about lipid awareness.
Myth 1
”High blood lipids” and “abnormal cholesterol” are the result of a lifestyle of eating more and moving less. Many people regard high blood lipids and abnormal cholesterol as “rich disease” brought about by eating more and moving less. Professor Zhou Yujie pointed out that abnormal cholesterol is not a simple lifestyle disease. Although it is related to diet and exercise, it can’t be solved just by avoiding food and exercising more. Among the factors leading to the occurrence of cardiovascular diseases, mainly coronary heart disease, risk factors such as age, gender, and family history of coronary heart disease are not modifiable. Among the factors that can be changed, the main one that causes serious harm is abnormal cholesterol, especially high LDL-C (low-density lipoprotein). In addition, having high blood pressure, diabetes and smoking habits are also important factors that lead to cholesterol deposition and coronary heart disease. Many thin people with low weight and strict vegetarians think that they will never have high blood lipids and abnormal cholesterol, but in fact, if they have the above risk factors, they may develop coronary heart disease as a result.
Misconception 2
High blood lipids means high triglycerides, high blood viscosity and slow blood flow. Lipid is a general term for the lipids contained in blood, which mainly includes cholesterol and triglycerides. The main cause of serious harm is abnormal cholesterol, especially high LDL-C (low-density lipoprotein). Studies have shown that an increase in triglycerides has failed to show an association with an increased relative risk of coronary heart disease and ischemic cardiovascular disease. And if there is too much LDL in the blood, which is deposited in the walls of the arteries, atheromatous plaques can form. The narrowing or rupture of blood vessels with plaque directly leads to acute heart attack, stroke and even sudden death. Therefore, LDL cholesterol is by far the most important indicator of lipid testing, not triglycerides.
Misconception three
No “arrows” in the physical examination test is normal. Many people today pay extra attention to the cholesterol indicators in their physical exam results, but few people find themselves with abnormal cholesterol problems because no “arrows” are found on their labs. Why are the statistics from epidemiologists so high? Professor Zhou Yujie said that the lipid treatment and target values for the general population and patients with coronary heart disease or diabetes, or who have had heart attacks or strokes, are different from the normal values shown on the test sheets. Their lipid target values are more stringent and should be lower than the reference value on the lipid panel, i.e., the “bad” cholesterol LDL-C should be less than 80 mg/dL or 2.1 mmol/L. The key groups, i.e., men over 40 years old, menopausal women, obese, yellow tumors, dyslipidemia, and family history of cardiovascular disease The cholesterol index for men over 40 years of age, menopausal women, obese women, those with yellow tumors, dyslipidemia, and a family history of cardiovascular disease should not just refer to the “not more than 3 mmol/L” index on the test. If possible, such people should have their blood lipids tested once a year.
Misconception 4
Abnormal cholesterol is a chronic problem, and even if it does not meet the standard, it will not be a problem. Cholesterol abnormalities are seen by many people as a chronic problem, just like high blood pressure and diabetes, and will not cause major health problems for a while. In fact, cardiovascular diseases, mainly coronary heart disease, are often inextricably linked to atherosclerosis, which is characterized by chronic progression, acute mutations, and inflammation throughout. The “bad” cholesterol is slowly deposited in the inner walls of the arteries to form atherosclerotic plaques, narrowing and blocking the blood vessels. Moreover, these plaques are like an “untimely bomb” that may rupture at any time, leading to acute heart attacks and strokes. If not controlled as early as possible, young patients will also suffer the same bad consequences of plaque rupture. In recent years, there are many young people who have suffered from sudden cardiovascular disease among movie stars. In a report published in 2004, in just 15 years, the rate of death due to coronary heart disease increased by 111% among male residents of Beijing between the ages of 35 and 44, and by 40% among women between the ages of 45 and 54.
Myth No. 5
Health care products can soften blood vessels and lower blood viscosity, and there are no side effects when taken. For patients with persistent hyperlipidemia, the medical profession recognizes that statins are the leading drugs for cholesterol-lowering treatment, and under the close guidance of clinicians, the efficacy and safety of statins are guaranteed. They prevent the absorption of bile acid or cholesterol from the intestine and promote the excretion of bile acid or cholesterol in the feces. Inhibit the synthesis of cholesterol in vivo, or promote the conversion of cholesterol, promote the expression of LDL receptors on cell membranes, and accelerate the breakdown of lipoproteins. Activate lipoprotein metabolizing enzymes to promote the hydrolysis of triglycerides. Blocking the in vivo synthesis of other lipids, or promoting the metabolism of other lipids.
1. High cholesterol is bad, the lower the cholesterol the better.
A: Wrong, cholesterol is mainly divided into low-density lipoprotein cholesterol (hereinafter referred to as LDL), and high-density lipoprotein cholesterol (hereinafter referred to as HDL), LDL higher than normal is bad, but HDL higher than 3.0 is greatly good, he is the scavenger of lipids. HDL can transfer excess cholesterol in the blood to the liver, where it is broken down into bile acid salts and excreted through the bile duct, thus forming a specialized pathway for lipid metabolism, also known as the “reverse transport pathway”.
2.Low density lipoprotein cholesterol (LDL) is the main cause of atherosclerosis.
A: The description is not entirely accurate. Under normal circumstances, LDL exists in a non-oxidized state, and non-oxidized LDL does not easily cause atherosclerosis (a thin porridge-like change in the wall of small arteries), but the latest 7th edition of Internal Medicine has clearly stated that LDL is oxidized into (Ox-LDL), and these oxidized LDL will be deposited in the inner wall of blood vessels, leading to atherosclerosis. If we think of LDL as a car running on the road, oxidized Ox-LDL is a rusty and faulty car, and HDL is like a trailer clearing roadblocks. If all the cars are in good condition, even if there are more cars, the traffic is still smooth, but the problematic, rusty cars on the road broken down will certainly be easy to cause traffic jams. That’s the reasoning.
3.As long as LDL-C is normal, other cholesterol should be left alone.
A: Wrong, even if LDL cholesterol (LDL) is normal, it does not exclude LDL is partially oxidized, which will still lead to atherosclerosis. In 1975, Dr. Miller and his research group found eight patients with normal lipid levels who had severe coronary heart disease (CHD is a representative disease of cardiovascular disease).