Cholesterol is a cheesy substance that coats the inner lining of blood vessels. It is carried in the blood as microscopic particles. The body needs cholesterol to build healthy cells.
For example, nerve cells have high fat content, but high levels of cholesterol can increase the risk of heart disease.
Eventually, these fatty deposits grow eating up the inner diameter of the vessel making it difficult for enough blood to flow through the arteries. Sometimes, those deposits can break suddenly and form a clot that causes a heart attack or stroke.
High cholesterol is often the result of unhealthy lifestyle choices, which makes it preventable and treatable.
A healthy diet, regular exercise and sometimes medication can help reduce high cholesterol. High cholesterol has no symptoms. A blood test is the only way to detect if one has it. Occasionally, people with high cholesterol have abnormal fatty deposits on the eyelids and tendons.
Factors that can increase the risk of bad cholesterol include:
Poor diet: Eating saturated fats that are found in animal products and trans-fats, which are found in some baked cookies, crackers and microwave popcorns, raise cholesterol levels.
Red meat and full-fat dairy products may also increase cholesterol.
Sedentary lifestyle: Exercises help boost the body’s ‘good’ cholesterol while increasing the size of the particles that make up ‘bad’ cholesterol, which makes it less harmful.
Obesity: Having a BMI (body mass index) of 30 or more puts one at a risk of high cholesterol.
Age: The body chemistry changes as one ages thus the risk of high cholesterol climbs. As one ages, the liver becomes less able to remove bad cholesterol.
Diabetes: High blood sugar contributes to higher levels of a dangerous cholesterol, which can also damage the lining of the arteries.
Smoking: Cigarette smoking damages the walls of the blood vessels, making them more prone to accumulate fatty deposits.
The following are the foods to avoid with fats:
•Trans-fats: They not only increase levels of bad cholesterol but also lower levels of good cholesterol. They are the most harmful fats.
Examples of trans-fats include: packaged cookies, cakes, doughnuts, pastries, potato chips, commercially fried foods, baked foods that contain shortening, buttered popcorn and any products that contain partially hydrogenated or hydrogenated vegetable oils.
•Saturated fats: They mostly are in meat and dairy products. They instruct the liver to produce more bad cholesterol. Examples of saturated fats include: fatty beef, lamb, pork, poultry with skin, lard and shortening, dairy products made from whole or reduced-fat milk, saturated vegetable oils such as coconut oil, palm oil and palm kernel oil.
Other foods that contain cholesterol and may be best avoided include: red meat, sausage, bacon and organ meats such as kidney and liver.
Complications of high levels of cholesterol
High cholesterol can cause a dangerous accumulation of cholesterol and other deposits on the walls of the arteries (atherosclerosis). These deposits (plaques) can reduce blood flow through the arteries which can cause complications such as:
Chest pain: If the arteries that supply the heart with blood (coronary arteries) are affected, one may develop chest pain (angina) and other symptoms of coronary artery disease.
Heart attack: If plaques tear or rupture, a blood clot forms at the plaque-rupture site blocking the flow of blood or breaking free and plugging an artery downstream.
If blood flows to any part of the heart stops a heart attack occurs, commonly manifested as severe crashing chest pain.
Stroke: A stroke occurs when a blood clot blocks blood flow to any part of the brain.
Healthy eating to avoid heart disease
A completely fat-free diet can also be harmful because it would deplete the levels of good carbohydrates, impair normal nerve and brain function and possibly increase inflammation.
The following are foods to include:
Fibre: Fibre is important for a healthy heart. Below are some cholesterol-friendly fibre options to consider. They include: fatty fish such as salmon, trout, albacore tuna, sardines, nuts, seeds, legumes, the skins of fruit, non-tropical natural vegetable oils such as olive oil, avocado oil, canola, and sunflower oil, oats, oat bran, chia, ground flaxseeds, beans, barley, psyllium, oranges, blueberries and Brussels sprouts.
Leaner cuts of meat and smaller portions, as well as low-fat or fat-free milk and yoghurts.
Treatment for cholesterol induced heart disease
The first line of defence against high cholesterol is lifestyle changes such as exercising and eating a healthy diet.
If the cholesterol levels remain high after the lifestyle changes then the doctor might recommend medication. The choice of medication or combination of medications depends on various factors which include: personal risk factors, age, health and possible drug side effects. The common choices include:
•Statins: They block the most important enzyme in the liver necessary for the synthesise of cholesterol. This causes the liver to remove cholesterol from the blood. Statins can also help the body reabsorb cholesterol from built-up deposits on the artery walls, potentially reversing coronary artery disease.
•Bile-acid-binding resins: The liver uses cholesterol to make bile acids, a substance needed for digestion. The medications cholestyramine, colesevelam and colestipol lower cholesterol indirectly by binding to bile acids. This prompts the liver to use excess cholesterol to make more bile acids, which reduces the level of cholesterol in your blood.
•Cholesterol absorption inhibitors: The small intestine absorbs the cholesterol from the diet and releases it into your bloodstream. The drug ezetimibe helps reduce blood cholesterol by limiting the absorption of dietary cholesterol.
Cholesterol is the second most important modifiable risk factor (after tobacco cessation) to prevent heart attack and stroke.
Dr Ngunga is a consultant interventional cardiologist at Aga Khan University Hospital, Nairobi