Most people regard cholesterol as a harmful fat that clogs blood vessels. It frequently makes headlines, and changing medical guidelines can be confusing. Should cholesterol be lowered? If so, to what level? The reality is that all of us have cholesterol in our blood. Cholesterol is an essential component of cell membranes and is required for the production of hormones and vitamin D.
After a meal, excess energy is stored as fat. Between meals, this stored fat is gradually released to provide fuel for the body’s organs, particularly the liver and muscles. Problems arise when excessive amounts of fat circulate in the bloodstream.
Blood is primarily water-based, and fats do not dissolve easily in water. When cholesterol levels become too high, it is deposited along the inner walls of blood vessels, forming yellowish accumulation called plaques. Over time, these plaques narrow and harden the arteries, restricting blood flow.
As the arteries narrow, the heart must pump harder to deliver blood to vital organs. Blood pressure rises, and the blood vessels become less elastic. The heart may eventually weaken and fail. Reduced blood flow to the kidneys can impair their function, leading to the accumulation of waste products in the body.
Peripheral arteries supplying the arms and legs can also become narrowed. As a result, the limbs may feel cold, and minor injuries may heal slowly. In severe cases, blood flow becomes so poor that tissues die, leading to gangrene.
The coronary arteries that supply oxygen-rich blood to the heart muscle are particularly vulnerable. If these vessels become blocked, parts of the heart muscle may be deprived of oxygen and die, resulting in coronary artery disease or a heart attack. A major heart attack can lead to sudden death.
Similarly, narrowing of the arteries supplying blood to the brain can cause strokes. Depending on the area affected, a stroke may result in memory loss, confusion, speech difficulties, paralysis, or permanent disability. Vascular dementia may also develop as blood flow to the brain declines.
Despite widespread awareness campaigns, many people never have their cholesterol levels checked. High cholesterol is often called a “silent killer” because it causes no symptoms for years. Many individuals discover their elevated cholesterol levels only after a heart attack, stroke or during a routine health check-up. Occasionally, fatty deposits around the eyes, known as xanthelasma, may provide a clue to the diagnosis.
The only way to diagnose and evaluate “high lipids” is to do a blood test called a lipid profile. It evaluates cholesterol and fat levels. Ideally, the sample should be taken after a 9–12-hour fast, during which only water is consumed. Food, milk, fever, infection, inflammation and pregnancy can alter the results.
The current guidelines for screening are
- Once between 9 and 11 years of age
- Again between 17 and 21 years
- Every 4–6 years thereafter
People with diabetes, hypertension, obesity, kidney disease, or a strong family history of heart disease require more frequent testing.
Desirable lipid levels
Test desirable
Total cholesterol < 200 mg/dL
Triglycerides < 150 mg/dL
HDL cholesterol > 60 mg/dL
LDL cholesterol < 100 mg/dL
Cholesterol/HDL ratio < 4.0
Cholesterol travels through the bloodstream attached to proteins called lipoproteins.
- LDL (Low-Density Lipoprotein) is known as the ‘bad’ cholesterol because it deposits cholesterol on artery walls.
- HDL (High-Density Lipoprotein) is the ‘good’ cholesterol. It acts as a scavenger, removing excess cholesterol from the bloodstream and transporting it back to the liver for disposal.
Several medical conditions can also raise cholesterol levels, including:
- Diabetes
- Hypothyroidism
- Chronic kidney disease
- Chronic liver disease
l HIV/AIDS
These conditions should be treated alongside cholesterol management.
High cholesterol may be inherited. Certain genetic conditions impair the body’s ability to remove LDL cholesterol from the blood.
More commonly, however, high cholesterol may appear to be genetic and run in families, but it is the result of unhealthy lifestyle habits shared and propagated by entire families.
If cholesterol levels are high:
- Eat a diet rich in fruits, vegetables, whole grains, legumes and lean proteins.
- Reduce sugar, refined carbohydrates and excess salt.
- Limit saturated fats and avoid trans fats.
- Choose healthy fats from fish, nuts, olive oil and canola oil.
- Restrict cooking oil consumption to about 500ml per person per month.
- Maintain a healthy body weight.
- Exercise for at least 30 minutes on most days of the week.
- Stop smoking.
- Limit alcohol intake to no more than one drink a day for women and two drinks daily for men.
Medication
Lifestyle modification remains the foundation of treatment, but if this fails and lipids are persistently elevated, medication may be required especially if cardiovascular or a stroke risk is significant.
- Statins are the most commonly prescribed drugs and are highly effective in lowering LDL cholesterol.
- Fibrates such as fenofibrate and gemfibrozil are useful for lowering triglycerides.
- Omega-3 fatty acids help reduce triglyceride levels.
- Niacin may lower LDL cholesterol, although it is now used less frequently.
- Recent advances in gene-editing technology have shown promise in correcting some of these inherited defects by targeting genes such as PCSK9.
High cholesterol becomes increasingly common after the age of 40, but it can affect younger people as well. Because it produces no symptoms until serious complications occur, regular screening and timely treatment are essential. Detecting and controlling abnormal lipid levels can prevent heart attacks, stroke, kidney disease and premature death.
The writer is a paediatrician and author of Staying Healthy in Modern India