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Blood Cholesterol/Cholesterol is a waxy, fat-like substance that’s found in all the cells in your body. Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods. Your body makes all the cholesterol it needs. Cholesterol is also found in foods from animal sources, such as egg yolks, meat, and cheese.
If you have too much cholesterol in your blood, it can combine with other substances in the blood to form plaque. Plaque sticks to the walls of your arteries. This buildup of plaque is known as atherosclerosis. It can lead to coronary artery disease, where your coronary arteries become narrow or even blocked.
Cholesterol, a major sterol in animal tissues, has a significant function in the human body. Cholesterol is a structural component of cell membranes and plays an integral role in membrane fluidity. Cholesterol is also important in the synthesis of lipid rafts which are needed for protein sorting, cellular signaling, and apoptosis [rx]. The characteristic structural feature of cholesterol is a fused four hydrocarbon ring referred to as a steroid nucleus, and a hydrocarbon tail consisting of eight hydrocarbon chain [rx]. The cholesterol ring is the precursor of steroid hormones including estrogen, progesterone, testosterone, as well as vitamin D. As a hydrophobic molecule, cholesterol is transported in the blood via spherical macromolecules in the plasma termed lipoproteins including chylomicrons, VLDL, LDL, and HDL.
What are HDL, LDL, and VLDL?
HDL, LDL, and VLDL are lipoproteins. They are a combination of fat (lipid) and protein. The lipids need to be attached to the proteins so they can move through the blood. Different types of lipoproteins have different purposes:
- HDL – stands for high-density lipoprotein. It is sometimes called “good” cholesterol because it carries cholesterol from other parts of your body back to your liver. Your liver then removes the cholesterol from your body.
- LDL – stands for low-density lipoprotein. It is sometimes called “bad” cholesterol because a high LDL level leads to the buildup of plaque in your arteries.
- VLDL – stands for very low-density lipoprotein. Some people also call VLDL “bad” cholesterol because it too contributes to the buildup of plaque in your arteries. But VLDL and LDL are different; VLDL mainly carries triglycerides and LDL mainly carries cholesterol.
Causes of Blood Cholesterol
Risk Factors– Blood Cholesterol
What health problems can high cholesterol cause?
- If you have large deposits of plaque in your arteries, an area of plaque can rupture (break open). This can cause a blood clot to form on the surface of the plaque. If the clot becomes large enough, it can mostly or completely block blood flow in a coronary artery.
- If the flow of oxygen-rich blood to your heart muscle is reduced or blocked, it can cause angina (chest pain) or a heart attack.
- Plaque also can build up in other arteries in your body, including the arteries that bring oxygen-rich blood to your brain and limbs. This can lead to problems such as carotid artery disease, stroke, and peripheral arterial disease.
Symptoms of Blood Cholesterol
Diagnosis of Blood Cholesterol
There are usually no signs or symptoms that you have high cholesterol. There is a blood test to measure your cholesterol level. When and how often you should get this test depends on your age, risk factors, and family history. The general recommendations are:
For people who are age 19 or younger
- The first test should be between ages 9 to 11
- Children should have the test again every 5 years
- Some children may have this test starting at age 2 if there is a family history of high blood cholesterol, heart attack, or stroke
For people who are age 20 or older
- Younger adults should have the test every 5 years
- Men ages 45 to 65 and women ages 55 to 65 should have it every 1 to 2 years
When looking at cholesterol levels, two different types are usually measured. The two types have different effects on cardiovascular health. In everyday language they are often referred to as “good” and “bad” cholesterol:
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HDL cholesterol – HDL (high-density lipoprotein) cholesterol levels are a measure of the proportion of “good” cholesterol in your total cholesterol. Normal to high HDL cholesterol levels are associated with a lower risk of cardiovascular disease than low HDL cholesterol levels.
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LDL cholesterol – LDL (low-density lipoprotein) cholesterol levels are a measure of the proportion of “bad” cholesterol. High LDL cholesterol levels are associated with a higher risk of cardiovascular disease.
The “total cholesterol” level is also measured. This describes how much cholesterol someone has in their blood overall. High total cholesterol levels tend to be unfavorable. It is best to measure total cholesterol and LDL cholesterol levels on an empty stomach. That is why people are asked to stop eating, and only drink water, twelve hours before being tested.
There is some disagreement about when cholesterol levels are “too high.” People are often diagnosed with hypercholesterolemia if their total cholesterol or LDL cholesterol is above the level that has been defined as “healthy.” HDL cholesterol levels below the threshold level are also considered to be unfavorable. These levels can be measured in two different units: either as milligrams per deciliter (mg/dL) or as millimoles per liter (mmol/L). The following levels are considered to be “good” in healthy people:
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Total cholesterol – Levels below 200 mg/dL (5.2 mmol/L)
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LDL cholesterol – Levels below 130 mg/dL (3.4 mmol/L)
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HDL cholesterol – Levels above 40 mg/dL (1 mmol/L) in men and above 50 mg/dL (1.3 mmol/L) in women
Some experts criticize the use of pre-defined threshold levels because it means that a large number of people are considered to have a health problem. Based on these definitions, a 2010 study by the Robert Koch Institute found that more than half of all Germans had high cholesterol.
Treatment of Blood Cholesterol
Nutrient Composition of Most Commonly Consumed Cholesterol-Containing Foods
| Food Item | Unit | One Egg a | Beef b | Cheese c | Chicken d | Butter e | Shrimp f | Two Eggs g |
|---|---|---|---|---|---|---|---|---|
| per | per | per | per | per | Per | per | ||
| 50 gm | 100 gm | 100 gm | 100 gm | 100 gm | 100 g | 100 gm | ||
| Nutrients | ||||||||
| Energy | kcal | 72 | 674 | 393 | 215 | 714 | 62 | 143 |
| Protein | g | 6.28 | 8.21 | 25 | 18.6 | 12.56 | ||
| Total lipid (fat) | g | 4.75 | 70.9 | 32.14 | 15.06 | 78.57 | 13.27 | 9.51 |
| Carbohydrate, by difference | g | 0.36 | – | – | – | – | 0.88 | 0.72 |
| Fiber, total dietary | g | – | – | – | – | – | 0 | |
| Sugars, total | g | 0.18 | – | – | – | – | – | 0.37 |
| Minerals | ||||||||
| Calcium, Ca | mg | 28 | 26 | 714 | 11 | – | 53 | 56 |
| Iron, Fe | mg | 0.88 | 0.72 | – | 0.9 | – | 0.32 | 1.75 |
| Magnesium, Mg | mg | 6 | 5 | – | 20 | – | – | 12 |
| Phosphorus, P | mg | 99 | 61 | – | 147 | – | – | 198 |
| Potassium, K | mg | 69 | 96 | – | 189 | – | – | 138 |
| Sodium, Na | mg | 71 | 26 | 607 | 70 | – | 566 | 142 |
| Zinc, Zn | mg | 0.65 | 0.82 | – | 1.31 | – | – | 1.29 |
| Copper, Cu | mg | 0.04 | 0.03 | – | 0.048 | – | – | 0.072 |
| Manganese, Mn | mg | 0.01 | – | – | 0.019 | – | – | 0.028 |
| Selenium, Se | µg | 15.3 | 6.6 | – | 14.4 | – | – | 30.7 |
| Fluoride, F | µg | 0.6 | – | – | – | – | – | 1.1 |
| Vitamins | ||||||||
| Vitamin C, total | mg | – | – | – | 1.6 | – | – | – |
| Thiamin | mg | 0.02 | 0.03 | – | 0.06 | – | – | 0.04 |
| Riboflavin | mg | 0.23 | 0.04 | – | 0.12 | – | – | 0.457 |
| Niacin | mg | 0.04 | 1.44 | – | 6.801 | – | – | 0.075 |
| Pantothenic acid | mg | 0.77 | 0.16 | – | 0.91 | – | – | 1.533 |
| Vitamin B-6 | mg | 0.09 | 0.11 | – | 0.35 | – | – | 0.17 |
| Folate, total | µg | 24 | – | – | 6 | – | – | 47 |
| Choline, total | mg | 147 | – | – | 59.7 | – | – | 293.8 |
| Vitamin B-12 | µg | 0.45 | 0.73 | – | 0.31 | – | – | 0.89 |
| Vitamin B-12, added | µg | – | – | – | – | – | – | – |
| Vitamin A, RAE | µg | 80 | – | – | 41 | – | – | 160 |
| Carotene, beta | µg | – | – | – | – | – | – | – |
| Carotene, alpha | µg | – | – | – | – | – | – | – |
| Cryptoxanthin, beta | µg | 4 | – | – | – | – | – | 9 |
| Vitamin A, IU | IU | 270 | – | – | 137 | 2857 | 177 | 540 |
| Lycopene | µg | – | – | – | – | – | – | |
| Lutein + zeaxanthin | µg | 252 | – | – | – | – | – | 503 |
| Vitamin E (alpha-tocopherol) | mg | 0.53 | – | – | 0.3 | – | – | 1.05 |
| Vitamin E added | mg | – | – | – | – | – | – | – |
| Tocopherol, beta | mg | 0.01 | – | – | – | – | – | 0.01 |
| Tocopherol, gamma | mg | 0.25 | – | – | – | – | – | 0.5 |
| Tocopherol, delta | mg | 0.03 | – | – | – | – | – | 0.06 |
| Vitamin D (D2 + D3) | µg | 1 | 0.3 | – | 0.2 | – | – | 2 |
| Vitamin D3 (cholecalciferol) | µg | 1 | 0.3 | – | – | – | – | 2 |
| Vitamin D | IU | 11 | 14 | 10 | – | – | 82 | |
| Vitamin K (phylloquinone) | µg | 3.4 | – | 1.5 | – | – | 0.3 | |
| Lipids | ||||||||
| h Fatty acids, total saturated | g | 1.56 | 29.5 | 19.64 | 4.31 | 50 | 0 | 3.126 |
| Fatty acids, total monounsaturated | g | 1.83 | 30.9 | – | 6.24 | – | – | 3.658 |
| Fatty acids, total polyunsaturated | g | 0.96 | 2.56 | – | 3.23 | – | – | 1.911 |
| Fatty acids, trans | g | 0.02 | – | 0.097 | – | – | 0.038 | |
| i Cholesterol | mg | 186 | 99 | 107 | 75 | 214 | 124 | 372 |
| Amino Acids | ||||||||
| Tryptophan | g | 0.08 | 0.05 | – | 0.207 | – | – | 0.167 |
| Threonine | g | 0.28 | 0.33 | – | 0.767 | – | – | 0.556 |
| Isoleucine | g | 0.34 | 0.37 | – | 0.924 | – | – | 0.671 |
| Leucine | g | 0.54 | 0.65 | – | 1.35 | – | – | 1.086 |
| Lysine | g | 0.46 | 0.69 | – | 1.509 | – | – | 0.912 |
| Methionine | g | 0.19 | 0.21 | – | 0.493 | – | – | 0.38 |
| Cystine | g | 0.14 | 0.11 | – | 0.249 | – | – | 0.272 |
| Phenylalanine | g | 0.34 | 0.32 | – | 0.721 | – | – | 0.68 |
| Tyrosine | g | 0.25 | 0.26 | – | 0.597 | – | – | 0.499 |
| Valine | g | 0.43 | 0.41 | – | 0.902 | – | – | 0.858 |
| Arginine | g | 0.41 | 0.53 | – | 1.169 | – | – | 0.82 |
| Histidine | g | 0.15 | 0.26 | – | 0.544 | – | – | 0.309 |
| Alanine | g | 0.37 | 0.5 | – | 1.089 | – | – | 0.735 |
| Aspartic acid | g | 0.66 | 0.75 | – | 1.659 | – | – | 1.329 |
| Glutamic acid | g | 0.84 | 1.23 | – | 2.714 | – | – | 1.673 |
| Glycine | g | 0.22 | 0.5 | – | 1.223 | – | – | 0.432 |
| Proline | g | 0.26 | 0.39 | – | 0.911 | – | – | 0.512 |
| Serine | g | 0.49 | 0.32 | – | 0.657 | – | – | 0.971 |
| Hydroxyproline | g | 0.09 | – | – | – | – | – |
