What is cholesterol?
Cholesterol is a waxy, fat-like substance found in the walls of cells in all parts of the body, from the nervous system to the liver to the heart. The body uses cholesterol to make hormones, bile acids, vitamin D, and other substances.
Why do some people have high blood cholesterol level?
Various factors can cause unhealthy cholesterol levels:
- Age and gender
- Diet - saturated fat, trans fat, cholesterol
- Physical inactivity
Where does the cholesterol come from?
Our liver produces most of the cholesterol found in our body; the rest of the cholesterol is contributed by the foods we eat.
Dietary cholesterol comes only from foods of animal origin, such as liver and other organ meats; egg yolks (but not the whites, which have no cholesterol); shrimp; and whole milk dairy products, including butter, cream, and cheese.
Are there different types of cholesterol in the blood? How can they affect me?
Cholesterol circulates in the bloodstream in packages called lipoproteins, which is a combination of cholesterol and protein. There are 2 main kinds of lipoproteins:
- Low density lipoprotein (LDL), commonly known as “bad” cholesterol because it carries cholesterol to tissues, including the arteries.
- High density lipoprotein (HDL), which is also called the “good” cholesterol because it takes cholesterol from tissues to the liver, hence removing it from the body.
If there is too much cholesterol in the blood, some of the excess can become trapped in artery walls. Over time, this builds up as ‘plaque’. The plaque can narrow vessels and make them less flexible, a condition called atherosclerosis or “hardening of the arteries”. This can happen to blood vessels anywhere in the body, including those of the heart, which are called the coronary arteries. When atherosclerosis affects the coronary arteries, the condition is called coronary heart disease or coronary artery disease.
How can I reduce my blood cholesterol level?
You can reduce your blood cholesterol level by modifying your lifestyle and diet. This includes maintaining a healthy weight through exercise and having a healthy balanced diet. If your blood cholesterol level does not achieve a desirable range despite lifestyle and diet modification, then your doctor may prescribe cholesterol-lowering medication.
- Keep total fat intake between 20 to 35 percent of calories for adults, with most fats coming from sources of polyunsaturated and monounsaturated fats.
- Consume less than 10% of calories from saturated fats and less than 300 mg cholesterol per day.
- Keep trans fat consumption minimal. It should contribute less than 1% of daily energy intake.
- When selecting and preparing meat, poultry, dry beans, and milk or milk products, make choices that are lean, low fat or fat-free. Choose fish, skinless poultry and lean meat.
- Aim for ‘2+2’ - 2 servings of fruits and 2 servings of vegetables per day1.Foods high in fibre, e.g. plant foods and wholegrains, can help reduce your risk of heart disease.
- Maintain a healthy body weight. Being overweight or obese increases your chances for having a low HDL, a high LDL and high triglycerides*.
- Exercise regularly – at least 30 minutes each day and 5 times a week or more. Regular physical activity can help you manage your weight and therefore help lower your LDL and triglycerides and raise HDL, improve the fitness of your heart and lungs, and lower blood pressure.
- Stop smoking as it raises triglycerides and lower HDL.
- Moderate alcohol intake to no more than 3 standard drinks for a man and 2 standard drinks for a woman in a day1
Triglycerides*, which are produced in the liver, are another type of fat found in the blood and in food. Causes of raised triglycerides are overweight/obesity, physical inactivity, cigarette smoking, excess alcohol intake, and a diet very high in carbohydrates (60 percent of calories or higher).
What is trans fat? Is it really bad for my health?
Trans fat is found mostly in foods that have been hydrogenated. Hydrogenation is a process in which hydrogen is added to unsaturated fat to make it more stable and solid at room temperature. Some trans fat also occurs naturally in animal fats, such as dairy products and some meat products.
The main sources of trans fat in the diet are from partially hydrogenated (hardened) oils found in foods such as cookies, crackers, pastries and fried foods. These fats are added for taste, texture and to maintain freshness or extend shelf life.
The main concern with trans fat is that it raises the risk of coronary heart disease by increasing LDL cholesterol and lowering HDL cholesterol.
What are plant sterols? Are they safe and good for me?
Plant sterols, sometimes called phytosterols, are naturally occurring chemicals found in plants. They are also found naturally in some vegetable oils, nuts, grain products, fruits and vegetables. The plant sterols used in food products are taken from soybean and tall pine-tree oils, combined with a small amount of canola oil.
Although the details are not fully understood, plant sterols have a similar chemical structure as cholesterol. Some studies have shown LDL cholesterol lowering effect. The American Heart Association’s (AHA) Therapeutic Lifestyle Changes diet2 recommends an intake of 2g of plant sterols a day for LDL cholesterol lowering effect.
Plant sterols in the form of supplements should be minimized. This is because excessive consumption of plant sterols may affect the absorption of fat-soluble vitamins.
- Health Promotion Board http://www.hpb.gov.sg
- Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III [ATP III]). NCEP Guidelines 2001