We often hear that cholesterol is bad. Sometimes, news breaks through the noise that there are two kinds and only one is bad. What is the full answer?
What Is Cholesterol?
Cholesterol is a waxy substance similar to fat. It is carried through the bloodstream and is stored in many of the body’s cells. Its biological role is to help create certain hormones and bile acids that help digest fat. It is essential for building cell walls in the brain and nerves, skin and muscles, the heart and liver, and elsewhere.
The body actually manufactures cholesterol itself, so it will be present even if none were consumed in foodstuffs. On average, about 75% of the total is made, while the other 25% comes from food.
Two Kinds of Cholesterol
Cholesterol is carried in the bloodstream by compounds called lipoproteins. There are two types: LDL (Low Density Lipoproteins) and HDL (High Density Lipoproteins). The first type, LDL, is the so-called bad cholesterol, HDL the good kind. Their reputations are gained from the different effect they have on arteries.
Arteries carry blood away from the heart, veins carry it back. But to do that efficiently, they have to be unobstructed and flexible. An obstructed artery produces higher blood pressure. Think of what happens when you put your thumb partly over the end of a hose. The water squirts farther because of the higher pressure. Arteries that are not flexible are more likely to break, just like a hose left too long in the sun that becomes stiff.
LDL (bad cholesterol) aids in the formation of plaque in arteries, causing them to narrow and harden. That condition is called atherosclerosis and is one of the main contributors to possible heart attack and stroke. HDL actually helps keep that plaque from building up on the artery walls.
How Much Is Bad?
Like anything, even bad cholesterol is only bad to one degree or another.
For an average adult, less than 200 mg/dL (milligrams per decaliter, of blood that is) total cholesterol is desirable, since the lower number correlates with a lower risk of coronary heart disease (CHD).
A number from 200-239 mg/dL is considered on the high end of the gray area. A number of 240 mg/dL is high, increasing the risk of CHD to double that of someone with a number of 200 mg/dL or below.
LDL is best kept below 100 mg/dL, with 100-129 mg/dL in the range of acceptable. Anything between 130-159 mg/dL is borderline, while 160-189 mg/dL is considered high. Anything above 190 mg/dL is very high.
But it’s possible to have too little as well, when measuring HDL.
About 40 mg/dL (for men) and 50 mg/dL (for women) is at the bottom of the good range for HDL. A number lower than this is correlated with increased risk of CHD. An HDL measurement of 60 mg/dL and above puts one into the safer range for protection against heart disease.
One reason for the relatively wide range is that there are other factors for risk of heart disease, including family history, lifestyle (such as smoking, excess alcohol, amount of exercise),and others. Another is the level of triglycerides present.
A Few Words About Triglycerides
Triglycerides are the most common type of fat in the body. Their levels are also measured whenever measuring cholesterol. Like cholesterol, they play a role in the risk of CHD and influence how risky one cholesterol level is over another.
Less than 150 mg/dL of triglycerides is normal, while 150-199 mg/dL is borderline. From 200-499 mg/dL is high, with anything above 500 mg/dL very high.
Overall, keeping the proper balance and level of cholesterol and triglycerides is one key to optimal health. The benefits are optimal blood pressure, low risk of CHD and improved odds of a healthy and long life.