If you have cholesterol, you’d know there are two types: LDL (low density lipoprotein) or the bad guy, and HDL (high density lipoprotein) or the good guy. Why is HDL cholesterol known as “good cholesterol”? Because it moves fat out of the arterial wall, and, thus, prevents or even helps stem diseases of the arteries. Now, one should keep in mind that this is not the only way in which fat can be moved out of the arteries. Tests done on mice, which lack HDL cholesterol, have proven otherwise.
Medical science uses non-HDL cholesterol to gauge arterial thickening. This is achieved by subtracting HDL cholesterol from the total cholesterol, and what one is left with is non-HDL cholesterol. We know that higher good cholesterol levels are associated with better heart health.
HDL can be raised by decreasing the intake of carbohydrates, weight loss, eating soluble fibre, aerobic exercises, and removal of transfats from the diet and by mild to moderate alcohol intake and smoking cessation. However, raising total HDL by using pharmacological drugs does not result in any benefits for the heart.
There is also the theory that people with larger than average cholesterolcarrying molecules are better off than those that have small dense particles.. This is similar to LDL or bad cholesterol, where larger molecules are less dangerous than small dense molecules. This concept was borne out by a study in Copenhagen of 100,000 people. The study showed an increase in all-cause mortality in men with HDL above 97 and in women with HDL above 135 mg.
In the normal course an HDL lower than 40 mg is bad news, and is associated with heart disease. A study in the Journal of the American College of Cardiology, which involved over 630,000 people, revealed that the risk of death, other than from heart disease, was higher in men who have more than 70 mg% and women who have more than 90 mg% of HDL. I must admit it, however, that the study addressed death from issues other than heart disease.
Researchers term the increased HDL as dysfunctional HDL. So, in essence, should one look just at the level of HDL? Perhaps not. It is the number of particles of HDL that one should focus on. The greater their number, the less is the chance of heart and other cardiovascular diseases.
Now, there is this emerging view that the level of HDL depends on your lifestyle. If you exercise, lose weight, and don’t smoke, you have a higher level of HDL. But I’d think one should not simply go just by the level of HDL. Instead, one should measure how effective your HDL is. The New England Journal of Medicine actually has an excellent article that talks about how the capacity of HDL to remove cholesterol can be measured, and that, I think, should be the ultimate test. But such tests are not yet commercially available.
Alot of research on cholesterol in the last decade has been an eye-opener, and better awareness would deter people who take medicines, some of which have severe side effects, in order to get the better of cholesterol. While the focus is now on looking at HDL function, and that higher levels of HDL may be dysfunctional, the right way to look at it is that it is the size of the particle that matters more. Because, like with LDL, it is believed that large particles are less dangerous than small dense particles, but I am yet to come across commercial tests that measure particle size in LDL. Much of this has been inferred indirectly by the level of triglycerides in the blood.
Are we then testing for the sake of testing? I have patients who can’t contain their joy when they show me their low LDL levels, and yet others who keep trying to raise their level of HDL. Perhaps, tests do not reveal a lot, because, if you ask me, tests are only effective when we can actually measure LDL size and HDL capacity to remove LDL cholesterol from the arteries.
