Cholesterol Chemistry || What Cholesterol Level is Good?

Cholesterol is a derivative of cyclopentane poly hydro phenanthrene. As early as the 18th century, cholesterol was found in gallstones. cholesterol symptoms

In 1816, the chemist Bencher named the substance with lipid properties cholesterol.

Cholesterol is widely present in animals, especially in the brain and nerve tissue, and is also high in kidney, spleen, skin, liver, and bile.

Its solubility is similar to fat, insoluble in water, soluble in solvents such as ether and chloroform. Cholesterol is an indispensable substance in animal tissue cells.

It is not only involved in the formation of cell membranes but also a raw material for the synthesis of bile acids, vitamin D and steroid hormones.

Cholesterol can also be converted into bile acids, steroid hormones, 7-dehydrocholesterol by metabolism, and 7-dehydrocholesterol are converted to vitamin D3 by ultraviolet radiation, so cholesterol is not a harmful substance.


On October 27, 2017, the list of carcinogens published by the World Health Organization’s International Agency for Research on Cancer was initially compiled and cholesterol was listed in the list of three types of carcinogens.

Cholesterol Definition

Cholesterol is also an important indicator of clinical biochemical tests.

Under normal circumstances, cholesterol synthesized by the body in the liver and taken from food will be converted into steroid hormones or become a component of the cell membrane, and the concentration of cholesterol in the blood will be kept constant.

When the liver develops severe lesions, the cholesterol concentration decreases. In patients with jaundice and nephrotic syndrome, cholesterol levels tend to increase.

Standard Intake

Cholesterol is mainly derived from the body’s own synthesis, and cholesterol in food is a secondary supplement.

For example, a 70kg bodyweight adult has about 140g of cholesterol, about 1g per day, 4/5 of which is metabolized in the body, only 1/5 need to be replenished from food, and 200mg of cholesterol is taken from food every day. It can meet the needs of the body.

The cholesterol absorption rate of only 30%, with the increase in cholesterol content of food, the absorption rate also decreased, 200mg equivalent to about one egg cholesterol content or cholesterol uptake 3–4 eggs. Experts recommend that 50mg ~ 300mg cholesterol per day is better.

Chemical Properties

In general, lipids are mainly divided into two major categories. Fat (mainly triglycerides) is the most abundant lipid in the human body and is a major source of energy in the body.

The other type is called lipid, which is the basic component of biofilm, accounting for about 5% of body weight, including phospholipids. In addition to glycolipids, there is also a very important one called cholesterol (cholesterol).

Cholesterol is present in the blood in lipoproteins and is present in several forms including high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and very-low-density lipoprotein cholesterol.

Most of the cholesterol present in the blood is a cholesterol ester that binds to fatty acids, and only 10% of the cholesterol is present in a free state.

High-density lipoproteins help clear cholesterol in cells, and low-density lipoproteins are generally considered a precursor to cardiovascular disease. The cholesterol content in the blood is between 140 and 199 mg per unit, which is a relatively normal cholesterol level.

Cholesterol is composed of the corpus callosum and alongside the chain. The total amount of cholesterol in the human body is about 0.2% of body weight.

In every 100 grams of tissue, bone contains about 10 mg, skeletal muscle contains about 100 mg, and internal organs are between 150 and 250 mg.

The liver and skin content is slightly higher. , about 300 mg. The brain and nerve tissue are the highest, containing about 2 grams per 100 grams of tissue, and the total amount is about 1/4 of the total body.

Cholesterol Function

Bile is produced in the liver and stored in the gallbladder. It is released into the small intestine and mixed with the digested fat. The function of bile is to turn large particles of fat into small particles, making it easy to interact with enzymes in the small intestine.

In the small intestine tail, 85% to 95% of the bile is reabsorbed into the blood, the liver reabsorbs the bile acid to circulate, and the remaining bile (5% to 15%) is excreted with the feces. The liver needs to produce new bile acids to make up for this 5% to 15% loss, which requires cholesterol.

Cell Membrane

Cholesterol is an important component of the cell membrane. The cell membrane is surrounded by every cell in the body. Cholesterol is its basic component, accounting for more than 20% of the membrane lipids.

It has been found that feeding animals with cholesterol-deficient foods result in increased erythrocyte fragility in these animals, which tends to cause cell rupture.

Studies have shown that at high temperatures, cholesterol can prevent the disorder of the bilayer; when the temperature is low, it can interfere with its ordering, prevent the formation of liquid crystals, and maintain its fluidity.

Therefore, it is conceivable that if there is no cholesterol, the cells will not be able to maintain normal physiological functions and life will be terminated.

Synthetic Hormone

The hormone is a chemical messenger that coordinates the metabolism of different cells in a multicellular organism. It participates in the metabolism of various substances in the body, including the metabolism of sugar, protein, fat, water, electrolytes and minerals.

It is very important to maintain the normal physiological functions of the human body.

Various hormones released by the adrenal cortex and gonads of the human body, such as cortisol, aldosterone, testosterone, estradiol, and vitamin D, are all steroid hormones, and the precursor substance is cholesterol.

How Cholesterol Works

There are two distinct and one-sided views on the role of food cholesterol. One view is that cholesterol is extremely harmful and cannot be eaten.

This view is one-sided because people who hold this view lack a clear understanding of the role of cholesterol in the human body.

In fact, cholesterol is a component of the cell membrane and is involved in the biosynthesis of some steroid hormones and bile acids. Because many other nutrients in cholesterol-containing foods are also abundant, if you eat too much of these foods, it is easy to cause nutritional imbalance, leading to anemia and other diseases.

It is best to use foods rich in dietary fiber in the diet, such as celery, corn, oats, etc. tea pigment in tea can reduce blood total cholesterol, prevent atherosclerosis and thrombosis, green tea is better than black tea, vitamin C And E can lower blood lipids and regulate blood lipid metabolism.

They are high in dark or green plants (vegetables, fruits) and beans. Limit high-fat foods: such as animal internal organs, vegetable oil does not eat animal oil. How Cholesterol Works

Drinking alcohol may increase the high-density lipoprotein in the blood and strengthen the prevention and treatment of hypercholesterolemia. The amount of alcohol consumed is not more than 20 grams per day (no more than 50 grams of white wine). Wine is suitable, but the intake must be strictly limited.

Foods with high cholesterol content include egg yolk, animal brain, animal liver and kidney, squid (squid), crab yellow, crab paste and so on. Crabs contain higher levels of cholesterol, 235 mg of cholesterol per 100 g of crab meat, and 460 mg of cholesterol per 100 g of crab. The content of cholesterol in pig liver is high. According to the analysis, about 368 mg of cholesterol is contained in every 100 g of pig liver.

Cholesterol Control Introduction

Low-density lipoprotein cholesterol (LDL-C) can cause damage to arteries; high-density lipoprotein cholesterol (HDL-C) has the function of clearing and clearing arteries. Here are some recommended dietary methods designed to reduce LDL-C levels in humans and increase HDL-C levels.

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Eat more fish

A study of the effects of omega-3 fatty acids (present in fish such as tuna, mackerel, mackerel, and sardines) on HDL-c showed that when the number of fish was eaten once a week or even once a day, Can effectively reduce the intake of saturated fat.

Eat more fiber-rich foods

Foods with very high fiber content such as whole grain and bread can effectively reduce the amount of LDL-c in the human body. Nutrition experts point out that in order to achieve the effect of affecting cholesterol levels, the fiber in the diet must reach 15 to 30 grams.

You can add a plate of blackberries to your breakfast, add half a bowl of lentils to your lunch, add a plate of whole wheat pasta to your dinner, and add 5 pairs of half-cut peaches as snacks.

Eat more soy products

Soy products such as tofu and puffed vegetable protein contain a natural phytochemical called isoflavones. Studies have shown that this chemical helps to remove the LDL-c that harms the arteries from the body.

Ingest a sufficient amount of vitamin C

Studies conducted at Tufts University in Massachusetts have shown that vitamin C levels in the blood are directly proportional to HDL-c levels in the human body.

Experts suggest that eating 3–4 servings of vitamin C-rich foods such as citrus fruits, potatoes, broccoli, broccoli, strawberries, papayas, and dark green leafy vegetables can increase the amount of vitamin C in human blood.

Thereby increasing the number of HDL-c in the body and ensuring the smooth flow of blood vessels.

Cholesterol is an indispensable nutrient for the human body. It is not only one of the structural components of the body, but also a raw material for the synthesis of many important substances.

Excessive consumption of cholesterol-containing foods can easily cause anemia and reduce the body’s resistance.

However, long-term intake of cholesterol is not conducive to good health, which will increase serum cholesterol levels and increase the risk of cardiovascular disease. Therefore, scientific dietary methods advocate the right amount of cholesterol.

Foods that contain no cholesterol and low cholesterol are all plant foods, egg whites, poultry, dairy, fish, etc.

The researchers also found that not smoking, drinking a little alcohol, and exercising several times a week to improve heart function are the three key factors to increase the amount of HDL-c in the body.

Eat less fatty foods

Animal liver, eggs, beef and mutton, and other red meats, foods with higher LDL-c content, often eat these foods, is not conducive to reducing the amount of cholesterol in the human body.

Nancy Ernst, a staff member at the National Heart, Lung, and Blood Institute in Maryland, points out that in any diet designed to lower cholesterol, the number of calories from saturated fat should be reduced to an all-day diet. 10% of the total amount of heat.

Because excess saturated fat can increase the burden on the body responsible for clearing the cholesterol system, leading to blockage of the arteries.

Redistribution of intake ratio

The body’s daily intake of fat is roughly divided into saturated fat (mostly found in meat and other foods), a variety of unsaturated fats (mostly found in vegetable oils) and single unsaturated fats (present in rapeseed oil and olive oil).

Experts suggest that changing the ratio of the above three fat intakes in the daily diet can reduce the amount of LDL-c in the human body.

For people with higher cholesterol levels in the body, the optimal ratio of the three fats is 7:10:13. In other words, the number of calories from saturated fat should be reduced to less than 7% of the total intake. the number of calories from a variety of unsaturated fats should be reduced to less than 10% of the total intake. The number of calories in a single unsaturated fat can be increased to more than 13% of the total intake.

Doctor reminds:

Patients diagnosed with high cholesterol should be regularly monitored and treated by a doctor.

Do not take anticoagulant drugs while taking vitamin E supplements.

The daily demand for vitamin E is 30 IU (International Unit of Vitamins). However, when doctors recommend taking vitamin E supplements to help lower cholesterol, doctors usually recommend at least 100 IU per day.

Although the expert’s opinion is that the dose of vitamin E is less than 600 IU, it is safe and harmless; but the experts also stressed that the specific amount, method, time and precautions to be taken must be in accordance with the doctor’s advice.

In general, there are two reasons for low cholesterol. First, secondary hypocholesterolemia, more common in hyperthyroidism, liver damage such as hepatitis, cirrhosis and so on.

The other is primary hypocholesterolemia, which is caused by an unbalanced diet, long-term vegetarian diet, partial eclipse, and low cholesterol intake.

Cholesterol Levels

High cholesterol is not good for the body, but low cholesterol can affect health. Cholesterol is involved in the composition of the cell membrane in the body and maintains and nourishes the cell membrane, maintaining the stability of the cell membrane.

If the blood cholesterol level is too low, the stability of the cell membrane will be weakened, resulting in a decrease in cell membrane elasticity, resulting in an increase in brittleness of the blood vessel wall.

In addition, cholesterol is an important raw material for the synthesis of steroid hormones in the body. It can be converted into progesterone after metabolism in the body, and then corticosteroids, progesterone, androgen, and estrogen can be synthesized from progesterone.

These hormones have important effects on the regulation of stress, immune function, and metabolism of water, fat, and protein.

If the cholesterol level is too low, it will lead to a decrease in the synthesis of corticosteroids, resulting in weakened stress, weakened immunity, weakened normal disease resistance, or reduced sex hormone synthesis, affecting normal sexual function, which is not conducive to human health.

After excluding the possibility of other diseases, to maintain the normal level of blood cholesterol, you must develop a balanced diet. When cholesterol is low, you can eat more fish, animal offal, eggs, and other foods.

High cholesterol food

Animal foods (fish, eggs, milk, etc.) generally contain cholesterol, while plant foods generally do not contain cholesterol. The following daily foods contain a lot of cholesterol and should be highly regarded:

  1. The pig brain (other animals have similar brains) contains a lot of cholesterol, which is a champion. Every 100 grams of pig brain contains 2571 mg of cholesterol (the sheep brain is 2004 and the bovine brain is 2447). Fortunately, eating pig brains is not common. If you eat the animal brain, it is better to not exceed one or two times a year.
  2. Animal internal organs, such as pig kidney, pig liver, pig lung, pig spleen, pig intestine (bovine, sheep, chicken, fish and other animal internal organs are also the same) contain more cholesterol, the approximate content is 200 ~ 400 mg of cholesterol per 100 viscera. Therefore, the internal organs of animals should be eaten as little as possible. If you want to eat animal internal organs, it should be no more than 2 times a month.
  3. Egg yolk eggs (other eggs such as duck eggs, goose eggs, quail eggs, etc.) contain a lot of cholesterol and are mainly concentrated in the egg yolk. One egg (in 50 grams) contains 292.5 mg of cholesterol. Therefore, the Chinese Dietary Guidelines 2007 issued by the Chinese Nutrition Society recommends that ordinary adults eat 0.5 to 1 egg per day. For patients with hyperlipidemia, do not exceed 2 or 3 eggs per week (yellow).
  4. Squid (or squid) contains 268 mg of cholesterol per 100 g of squid (fresh weight, moisture content 80.4%). If you want to eat squid, it is better to not exceed one or two times a week.
  5. Shellfish, such as fresh shellfish, scallops, oysters, scallops, abalone, alfalfa, snails, etc. usually contain more cholesterol, and its content is generally 100~200 mg/100 g. These foods are expensive, have limited resources, and have low consumption.
  6. Others, animal fats such as butter, butter, sheep oil, lard, and butter contain more cholesterol. Moreover, the saturated fatty acids in these oils can also promote the liver to synthesize more cholesterol. Therefore, animal fats should be avoided.

Cholesterol-rich foods are as described above. Of course, controlling cholesterol intake is only one of the measures to prevent elevated blood cholesterol and lower elevated cholesterol, not all.

Although cholesterol intake in the diet is not the main source of cholesterol in the blood, controlling the intake of cholesterol in the diet (avoiding excessive cholesterol intake) is still preventing and treating dyslipidemia, hypertension, coronary heart disease, atherosclerosis, etc. An important measure of cerebrovascular disease.

Reduce cholesterol

  1. Eat less or not eat foods such as animal viscera, egg yolk, and other high cholesterol, control the intake of cholesterol in the diet (less than 300 mg per day). The main cholesterol in the blood (70%) is synthesized by the liver, and only a small part (30%) is derived from food. Therefore, relying solely on reducing cholesterol intake does not fundamentally treat high cholesterol, but it controls the cholesterol intake in food. Lowering cholesterol is still helpful. According to the standards recommended by the American Heart Association, the daily intake of cholesterol should be less than 300 mg or less, and the cholesterol in one egg yolk is 250–290 mg; 100 grams of boiled pork has higher cholesterol in the liver. Mg.
  2. Eat less fat and oyster sauce to reduce the intake of saturated fat. Saturated fat is widely found in meat, eggs, and dairy foods, especially in fat, oyster sauce, and viscera. Saturated fat has the effect of promoting the growth of blood low-density lipoprotein cholesterol (LDL-C), which is even more effective than cholesterol itself.
  3. Eat more fruits, vegetables, and algae, such as konjac, fungus, kelp, wakame, onions, pumpkins, sweet potatoes, etc. These foods are rich in dietary fiber to help cholesterol excretion. The main way for the body to excrete cholesterol is through bile, the liver uses cholesterol to synthesize cholic acid, and bile acid is excreted into the gastrointestinal tract to participate in fat digestion. After that, a portion of the bile acid metabolite is reabsorbed back into the blood “waste utilization”, another part the cholic acid metabolite is excreted with the feces. The role of dietary fiber is to adsorb more bile acid metabolites and discharge them instead of recycling them. In this way, the liver “has to use” more cholesterol to synthesize cholic acid to supplement the loss of bile acid. Numerous studies have confirmed that increasing dietary fiber intake has a clear effect on lowering cholesterol.
  4. Monounsaturated fatty acids contained in olive oil, tea oil, corn oil, and rapeseed oil have the effect of lowering low-density lipoprotein cholesterol (LDL-C). It can be mixed with a vegetable oil such as soybean oil and peanut oil in daily diet.
  5. Fish oil and lecithin has the effect of lowering blood lipids, but their effect is mainly on the increase of triglyceride, and the effect of lowering cholesterol is small (of course, it is still useful).
  6. Vitamin C, vitamin E, and other anti-oxidant ingredients cannot directly reduce the cholesterol in the blood, but help to reduce the harm of cholesterol to blood vessels.

Drug example

Lipid-lowering drugs for improving cholesterol metabolism disorders

For example, the fourth generation of Junshan Jiangzhi Ning Granules, Shuxin Jiangzhi Ning tablets, the former is more widely used and the curative effect is more precise.

Lipid-lowering drugs based on lowering plasma cholesterol


1 Bile acid sequestrants: such as cholestyramine (cholestyramine) and colestipol (nothing).

2 statins, HMG-CoA reductase inhibitors, are currently the most widely used lipid-lowering drugs in clinical practice. They have been used clinically with lovastatin, simvastatin, pravastatin, fluvastatin. Defects can cause rhabdomyolysis, especially when combined with fibrates.

The main drugs to prevent cholesterol from being oxidized are

Astaxanthin, lutein, b-carotene, CoQ10, anthocyanin, Ganoderma spores, tea polyphenols, etc. among which astaxanthin is the strongest, clinical studies have also confirmed that when volunteers take 1.8, 3.6, 14.4 per day After 2 weeks of 21.6 mg astaxanthin, the LDL oxidation time was prolonged by 5.0%, 26.2%, 42.3%, and 30.7%, respectively, thereby preventing the occurrence of atherosclerosis.

Those who receive estrogen insulin or certain drugs (such as niacin, vitamin E, heparin, etc.) can also increase, astaxanthin can significantly increase human high-density lipoprotein cholesterol.


Lipid refers to lipids in plasma, including four categories:

(1) Triglycerides and a small amount of diglyceride monoester;

(2) Cholesterol and cholesterol esters;

(3) Phospholipids, mainly phosphatidylcholine;

(4) Free fatty acids.

Clinical hyperlipidemia refers to a concentration of fasting plasma triglycerides or cholesterol that exceeds the normal range.

In fact, the blood lipids in the human body exist in the form of various types of lipoproteins, which are also divided into four categories:

(1) Chylomicrons, the main component of which is triglyceride.

(2) Very low-density lipoprotein, accounting for about 5% to 10%, the main component is triglyceride;

(3) Low-density lipoprotein accounts for about 25%, and the main component is cholesterol;

(4) High-density lipoprotein accounts for about 45% to 50% of the main components are phospholipids and cholesterol.

There are two units for measuring cholesterol. One unit is mmol/l, and the total cholesterol measurement is 5.2 mmol/L or less. The other unit is mg/dl, and the total cholesterol measurement of 200 mg/dl or less is normal.

The Reason

Improper diet

Excessive consumption of foods containing high cholesterol, such as heart, liver and other animal internal organs. Excessive intake of cholesterol in the body causes high total cholesterol, which is one of the common causes of high total cholesterol.

Obstructive jaundice

At this time, due to obstruction of bile discharge, lipoprotein-X and hypersecretion of intrahepatic cholesterol were observed in the blood, and the increase in free cholesterol was dominant. It causes high total cholesterol, so obstructive jaundice is one of the reasons for the high total cholesterol.

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When cholesterol is consumed intensively, it causes hypercholesterolemia, which leads to the so-called “rich disease” such as coronary atherosclerotic heart disease.

US researchers reported on the 17th that their experiments with experimental mice showed that high levels of cholesterol in the blood would accelerate the growth of prostate cancer. A large-scale study has shown that controlling elevated cholesterol levels not only reduces the risk of heart disease but also helps prevent kidney disease such as kidney failure.

Researchers at the Blyham Women’s Hospital in Boston, USA, conducted a study of 4,48 healthy men. The creatinine test confirmed that these men did not have any kidney disease at the beginning of the experiment. After 14 years of follow-up, it was found that for those with total cholesterol values. for high and low HDL cholesterol values, their creatinine values were significantly increased more than twice the upside than the common people during this period occurs, which indicates that they are suffering from kidney failure and the like kidney disease risk was significantly increased.

In addition, the glomerular filtration rate (GFR) of these people usually shows a corresponding decline, and the reduction of GFR itself means that the kidneys have abnormal effects on the filtration of poisons or metabolic wastes in the body.

Researchers suggest that controlling healthy people’s abnormal cholesterol levels through a healthy diet may help the kidneys stay normal. At the same time, people with a risk of kidney dysfunction and high cholesterol levels should discuss the use of lipid-lowering drugs with their doctors.

According to the Asia-Pacific Cardiovascular Disease and Stroke Survey, for every unit of cholesterol (1mmol/L) in Asians, the risk of death from cardiovascular disease increases by 35%, and the risk of blood vessel-related stroke increases by 25%. According to the survey, the life expectancy of men with high cholesterol is four to nine years shorter than those with lower cholesterol.

The researchers observed the participants for a short period of 16 years and a long period of 34 years. Cholesterol is known to block or narrow the heart to the heart, and for men and women, it can be said to be the main cause of heart disease.

Sanjay Bhandari

Hello Friends, My name is Sanjay Bhandari. I am a chemistry Teacher.

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