LDL Cholesterol Levels Not Giving an Accurate Picture of Heart Health
The cholesterol story is getting interesting. It used to be that “high cholesterol”—meaning high total cholesterol—caused people to worry about heart health. Then they realized it was more important to look a little closer at the two types of cholesterol—the “good” and “bad” cholesterol, which actually refers to the carriers of the cholesterol rather than the cholesterol itself. LDL cholesterol is considered bad, and HDL is considered good. High LDL cholesterol levels and/or low HDL cholesterol levels are considered risks for heart disease.
Or so we thought.
What most people do not realize is that LDL cholesterol is not measured. It is simply calculated based on other measured levels. This calculation, known as the Friedwald calculation, came about because it is much less work (read: less expensive) to calculate rather than measure. The calculation uses total cholesterol, HDL cholesterol and triglyceride levels to determine LDL. So when your doctor tells you that your LDL cholesterol is high, borderline, or even low, remember that this is only a rough estimate.
A recent study published in the Journal of the American College of Cardiology is shedding some light on this topic. “In our study, we compared samples assessed using the Friedwald equation with a direct calculation of the LDL cholesterol. We found that in nearly one out of four samples in the ‘desirable’ range for people with a higher heart disease risk, the Friedwald calculation had it wrong,” stated lead researcher Seth Martin, MD.
Some people with Friedwald-calculated LDL levels thought to be protective of heart health were actually at higher risk. This was true particularly in people who also had high triglyceride levels. The researchers suggest looking at “non-HDL” levels, which includes LDL as well as VLDL and IDL levels. Non-HDL levels can be found on the standard blood tests, and so are suggested as a more accurate, yet cost-effective, marker of heart health.
These researchers are headed in the right direction. However, what we really need to be looking at is the state in which the LDL particles are in. Particle size, particle number, and LDL oxidation levels give an even more accurate view of what is really happening in the arteries when it comes to cholesterol. I cover this concept more extensively in my book, Heart of Perfect Health, which is available through my PBS show of the same name. Integrative and functional medicine doctors are familiar with these cholesterol tests. You can find one here: http://www.acam.org or http://www.functionalmedicine.org