Cholesterol: Between HDL & LDL

Basically, cholesterol in and of itself is not a bad thing. It is a lipid that acts as an important building block of the cell membrane. However, if there is an excess of cholesterol, it can accumulate in the blood and on the vessel walls and lead to hardening of the vessels – the so-called arteriosclerosis. This increases the risk of circulatory disorders, thrombosis, heart attacks and strokes.

Around 80 percent of cholesterol is formed by the body itself. Only a small part is consumed through food. It is absorbed from the intestines, after which special receptors on the liver regulate the concentration in the bloodstream. The cholesterol level is continuously monitored by the liver – if it is too low, messenger substances for new formation are released. In excess, on the other hand, it develops its harmful effects.

HDL & LDL – what’s the difference?

In order to be transported in the blood, cholesterol is “packaged” in small lipoproteins. A distinction is made in the blood between total cholesterol, low-density lipoproteins (LDL) and high-density lipoproteins (HDL). LDL in particular is of particular importance when it comes to the harmful effects on the vessel walls. The following applies: the lower the LDL cholesterol levels, the lower the risk of cardiovascular disease.

What LDL target values ​​should be aimed for?

• healthy people, with low risk/no risk factors: LDL cholesterol below 116 mg/dl (<3.0 mmol/l)
• Healthy people with a moderately increased risk (e.g. overweight or slightly elevated blood pressure): LDL cholesterol level below 100 mg/dl (<2.6 mmol/l)
• Patients at high risk (e.g. people with pronounced high blood pressure, genetically caused high cholesterol levels or smokers): LDL cholesterol below 70 mg/dl (<1.8 mmol/l)
• Patients at very high risk (e.g. people with heart disease or diabetes): LDL cholesterol target value below 55 mg/dl (<1.4 mmol/l)
• Patients at very high risk who experience a second event within two years of statin therapy: target LDL below 40 mg/dl (<1.0 mmol/l)

Diet & Cholesterol

Elevated cholesterol levels often occur together with obesity – but this does not have to be the case. If those affected have a few kilos too much on their ribs, weight reduction can actually have a positive effect on cholesterol levels. Therefore, a healthy diet is considered an important factor in lowering cholesterol levels. The basis is often more vegetable and less animal fats, as this has a positive effect on the cardiovascular system. However, if the values ​​are much too high, a change in diet alone is usually not enough. The situation is different when the triglyceride levels are elevated – these can be influenced quite well through diet. A healthy lifestyle is also important: regular exercise and avoiding alcohol and nicotine can help.

A balanced diet with a positive influence on cholesterol levels includes:

• Lots of fresh fruit and vegetables and salads
• legumes
• whole grain products
• Fisch
• nuts
• vegetable oils

Statins: Drug lowering of cholesterol

Statins belong to the so-called inhibitors of HMG-CoA reductase, this enzyme is an intermediate product of cholesterol synthesis. They suppress the formation of cholesterol – this is compensated for by increased absorption from the blood plasma. Drugs such as simvastatin, atorvastatin, lovastatin, fluvastatin and pravastatin are indicated for hypercholesterolemia and also for the prevention of cardiovascular events. Therapy with statins causes a significant reduction in heart attacks and deaths.

So-called pleiotropic effects are also ascribed to this class of substances, i.e. the simultaneous favorable influence on other parameters apart from the mere reduction in cholesterol. Experts discuss improving the function and protection of the vascular endothelium as well as antioxidant and anti-inflammatory effects. Statins lower the level of the “bad” cholesterol in the blood, the LDL.

How are cholesterol-lowering drugs taken?

The dosage range for all statins is 5 to 80 mg per day as a single dose. The tablets should be taken in the evening, since the body’s own cholesterol synthesis is highest at night and can thus be inhibited. The 80 mg dose is only recommended for patients with severe hypercholesterolaemia and at high risk of cardiovascular complications, who have not met therapy goals with lower doses and where the benefits of the treatment are expected to outweigh the potential risks.

Patients being treated with simvastatin should not drink grapefruit juice during therapy. Components of the fruit inhibit cytochrome P450 enzymes in the liver, which inhibits the metabolism of the drug. Simultaneous intake is associated with an increased risk of adverse drug reactions (ADRs). Therefore, concomitant use of CYP3A4 inhibitors such as clarithromycin and ketoconazole should be avoided. It is also possible to switch to fluvastatin, which is not metabolised via CYP3A4.

What side effects can occur?

Myalgia (muscle pain) and myopathies (inflammatory or degenerative muscle diseases) can often occur during therapy with statins. Rarely, it can lead to rhabdomyolysis. This term describes a muscle cell death in the skeletal and cardiac muscles. Possible consequences are acute renal failure. The risk is dose-dependent. Other side effects are headaches, gastrointestinal complaints, exanthema and sleep disorders. Statins are contraindicated in patients with risk factors for rhabdomyolysis, liver disease, and elevated serum transaminase levels. Other interactions exist, for example, with amiodarone, verapamil, amlodipine and diltiazem.

Statins are contraindicated during pregnancy and lactation. They should only be given to women of childbearing potential if pregnancy is unlikely to occur in these patients. If a patient plans to become pregnant or becomes pregnant, the doctor should be informed immediately and the drug should be discontinued because of the potential risk to the foetus.