What are blood lipid levels?
The most important blood lipid values include the blood levels of triglycerides and cholesterol:
Triglycerides (neutral fats) belong to the group of dietary fats. They serve the body as an energy reserve and are stored in adipose tissue until needed. Cholesterol, on the other hand, can be absorbed from food as well as produced in the liver and intestines. It is an important component of cell walls. In addition, bile acids, vitamin D and steroid hormones are produced from cholesterol.
Lipoproteins
Since fats (lipids) are insoluble in water, they must be transported in aqueous blood in the form of lipoproteins: Lipoproteins consist of the lipids (inside) and a water-soluble surface of proteins (outside). Depending on their composition and task, a distinction is made between different lipoproteins:
- Chylomicrons: transport lipids from food (such as triglycerides, cholesterol) from the intestine to the liver and adipose tissue.
- LDL (low density lipoprotein): transports mainly self-produced cholesterol from the liver to other cells of the body (as LDL cholesterol); at high blood concentrations it is deposited on the walls of blood vessels, causing or accelerating arteriosclerosis.
- HDL (high density lipoportein): transports (as HDL cholesterol) excess cholesterol from the body cells back to the liver, where it can be broken down.
LDL cholesterol is considered “bad” because it promotes the development of atherosclerosis. In contrast, the “good” HDL cholesterol can protect against vascular calcification.
When are blood lipid levels determined?
Blood lipid levels are determined, among other things, when lipid metabolism disorders are suspected and to monitor the success of a lipid-lowering therapy (for example, diet or medication).
Guide values for blood lipid values
In order for the doctor to determine the blood fat values, he takes blood samples. Since fat enters the blood through the ingestion of food, the blood sample should be taken on an empty stomach. Ideally, the patient should not have eaten anything for eight to twelve hours and should have drunk at most water or unsweetened tea.
For healthy adults without risk factors for vascular calcification, the following guideline values apply:
|
Blood lipids |
Reference values |
|
LDL |
< 160 mg/dl |
|
HDL |
Women: 45 – 65 mg/dl Men: 35 – 55 mg/dl |
|
Total cholesterol |
before the age of 19: < 170 mg/dl 20th – 29th year of life: < 200 mg/dl 30th – 40th year of life: < 220 mg/dl after 40 years of age: < 240 mg/dl |
|
Triglycerides |
≤ 200 mg/dl |
|
VLDL |
< 30 mg/dl |
In people who have no other risk factors for atherosclerosis (such as high blood pressure), the LDL/HDL quotient should be below four. In contrast, a quotient below three is recommended for people with such other risk factors, and a quotient below two is recommended for people who already have atherosclerosis, for example.
The LDL/HDL quotient has meanwhile lost some of its importance when it comes to estimating cardiovascular risk. Apparently, extremely high levels of “good” HDL cholesterol (above about 90 mg/dl) do in fact increase the risk of atherosclerosis. With HDL cholesterol, therefore, the rule is not: the more, the better.
When are blood lipid levels too low?
When are blood lipid levels too high?
If blood lipid levels are too high, this is called hyperlipidemia. The cause can be a lipometabolic disorder. In most cases, an unhealthy lifestyle causes triglycerides, VLDL and LDL to be too high and HDL to be low. Lack of exercise, a diet high in sugar and fat, and obesity often play a major role.
Chronic diseases such as diabetes mellitus, Cushing’s disease, gout and kidney dysfunction can also lead to high blood lipid levels.
Values also rise during pregnancy, but normalize after delivery.
Various medications such as corticoisteroids also increase blood lipids.
What to do if blood lipid levels change?
Since low blood lipid values are only of disease value in very rare cases, therapy is limited to regular measurement and checking the medications taken.
A healthy diet with little saturated fatty acids and sufficient exercise can lower and normalize the values. If you are overweight, you should lose weight. It is also advisable to avoid alcohol and nicotine. If these basic measures are not effective, the doctor prescribes drugs such as statins or cholesterol absorption inhibitors to lower the elevated blood lipid levels.
