Cholesterol's connection to heart disease
By Clare E. Urwin
SURABAYA (JP): What exactly is cholesterol anyway? Well, for a start, it's the one component in our diet which causes more debate and argument than almost anything else. Even the word brings fear to some. We are constantly bombarded by advice and warnings about cholesterol, while at the same time most modern food advertising seems to claim that it's free of the stuff.
Middle-aged men are urged from all sides to watch their cholesterol in order hopefully to lower it, and thereby reduce their risk of a heart attack. With almost religious zeal we are told to stop eating egg yolks and to start taking fish oil supplements. What's going on?
The cholesterol controversy is complicated. Even though it's such a serious concern for many people, numerous unresolved issues still remain. One day the media seems filled with reports of new findings and declarations, yet the next day there appears just as many counterclaims. It's not surprising we are confused.
Most people know that too much cholesterol is in some way connected to heart disease. It is. But the belief that by using drugs or limiting fat intake we can lower blood cholesterol and easily reduce heart attacks is now questioned.
High cholesterol continues to be regarded as a risk factor in heart disease, but so is smoking, high blood pressure, lack of exercise, genetic predisposition and a bad diet. Risk factors are complex and individual. There are no simple answers.
Nevertheless, the fact remains that in heart disease, certain issues are understood well enough to make recommendations. Keeping cholesterol levels in check is one of them. So it seems to be common sense to play it safe and do exactly that.
So, what is cholesterol and what is its connection to heart disease?
Contrary to the negative publicity surrounding it, in reality cholesterol is essential to maintaining life. It's a soft waxy substance, naturally occurring in the body and produced by the liver in varying quantities.
Cholesterol is needed to build cell membranes and to form sex hormones. It is required for the synthesis of Vitamin D and is an important structural part of the protective covering of our nerves.
The liver makes all the cholesterol the body normally needs, but there are many dietary sources of it too. A major point of confusion is the difference between dietary cholesterol, what you eat in foods, and blood or serum cholesterol, which circulates in the blood. When a doctor says watch your cholesterol, he or she is referring to the level in your blood.
Eating high-cholesterol foods may have a small relationship to blood cholesterol level, but it's far less important than saturated or trans fat intake. For instance, cholesterol is only found in animal products, but some highly saturated fats from plants, such as coconut and palm oil, do raise blood cholesterol levels in humans.
Cholesterol is found in foods such as eggs, shellfish, meat and dairy products. People with coronary heart disease, raised blood levels or who have high risk factors are probably wise to avoid too many cholesterol-rich foods.
However don't become overzealous. Eggs may contain cholesterol but they are a very healthy food and the yolks contain the valuable Omega 3 essential fatty acids, which actually protect the heart.
There are two types of cholesterol in the blood -- low density lipoprotein (LDL) and high density lipoprotein (HDL). A surplus of LDL (commonly called "bad" cholesterol) is a risk factor in "furring" the arteries and forming the plaques which lead to atherosclerosis, heart disease and stroke.
On the other hand, HDL (often called the "good" cholesterol) actually helps to remove cholesterol from the tissues and deliver it to the liver for excretion. The ratio between the two should ideally be 3:1 in favor of the HDL.
However, many of us have raised levels of LDL and reduced HDL, upsetting the ideal balance and allowing potential harmful cholesterol to build up in the body.
The facts are clear: LDL cholesterol levels are increased by a high intake of saturated fats. These fats are found in red meat, full-fat dairy products and fried foods. The more of these foods that we eat, the higher our cholesterol levels are likely to be.
But even more damaging are the trans fats (hydrogenated fats) found in many commercial margarines and cooking oils, and the foods made from or cooked with them. They raise the bad LDL, but also reduce HDL, the good cholesterol. This means that junk food is far worse for you than butter!
Having a high blood count is often determined more by good luck than by good management. Some families are genetically blessed with low total cholesterol and high HDL levels, regardless of diet or lifestyle. Others have hereditary problems that significantly increase the risk of high cholesterol.
A blood test to determine blood cholesterol levels is now fairly routine when having a medical checkup. There will be three typical readings, expressed in milligrams per deciliter. Total cholesterol, HDL cholesterol and Triglycerides.
Triglycerides are another type of fat found in the blood, and evidence suggests that higher than normal levels can also contribute to an increased risk of heart disease, particularly in women, diabetics and older people.
Often a reading for LDL will be included in your test, as well as a figure for the ratio of total cholesterol to HDL. Total cholesterol below 200 is considered normal, 250 or more is high.
HDL should be above 35 for a man and above 45 for a woman. With the ratio, the lower the number the better. For men, 4.2 to 7.3 is average; for women it's 3.9 to 5.7.
The recommendations for lowering your blood cholesterol level echo the advice for having a healthy heart. Adopt a low-fat diet, lose weight if necessary, exercise regularly, manage stress sensibly and if you smoke -- stop. Eating more of the foods that seem to lower production of LDL or increase production of HDL will also help. (See today's Q&A)
Fish oils have the effect of lowering blood triglycerides and cholesterol. The Omega 3 fatty acids found in oily fish such as mackerel, herring, sardines, tuna and salmon will also thin the blood and help prevent blood clots. Try to eat some twice a week.
Moderate diet and lifestyle changes can usually reduce cholesterol levels or keep them in a desirable range. The controversy really starts when cholesterol reducing drugs are prescribed. However, that, as they say, is another story.
Play it safe and use your common sense. Watch your cholesterol levels, by all means, but don't become obsessed with them. Good luck.
-- The writer is a nutritionist and health adviser based in Surabaya. Please feel free to ask the writer questions through her e-mail address: email@example.com.