How To Interpret Cholesterol Test Results
Marks Daily Apple
by Mark Sisson: Setting
Yourself Up to Win: A Body By Science Approach
Before we get
into the big job of interpreting cholesterol numbers, let's review
what cholesterol actually is.
is cholesterol: a waxy steroid of fat that serves as an essential
structural component of cellular membranes and in the production
D, and bile acids. Contrary to what the terminology indicates,
there's actually only one "type" of cholesterol in the human body,
and it's called, quite simply, cholesterol. What we think of when
we use the word "cholesterol" is actually a lipoprotein
a fatty conglomerate of protein and lipids that delivers cholesterol
and fat-soluble nutrients to different parts of the body. It's not
just free cholesterol floating around in your blood; it's cholesterol
bound up by lipoproteins.
So LDL, HDL,
VLDL, all those (in)famous measurements we get at the doctor's office
are just different types of lipoproteins. They're not actually cholesterol.
I discussed this briefly a couple
years back, and there's always Griff's
big primer in the forum, so take the time to go check out both.
And also take a peak at The
Definitive Guide to Cholesterol for review.
talk about the most commonly bandied-about cholesterol numbers:
LDL-C and HDL-C. What do they really mean? What are they actually
what these numbers mean, let's play the freeway analogy game. Both
LDL-C and HDL-C, the standard, basic readings you get from the lab,
do not reflect the number of LDL or HDL particles the number of
lipoproteins in your serum. Instead, they reflect the total amount
of cholesterol contained in your LDL and HDL particles. Hence, the
"C" in LDL/HDL-C, which stands for "cholesterol." Measuring the
LDL/HDL-C and then making potentially life-changing health decisions
based on the number is like counting the number of people riding
in vehicles on a freeway to determine the severity of traffic. It's
data, and it might give you a rough approximation of the situation,
but it's not as useful as actually counting the number of vehicles.
A reading of 100 could mean you're dealing with a hundred compact
cars, each carrying a single driver, or it could mean you've got
four buses carrying 25 passengers each. Or it could be a couple
buses and the rest cars. You simply don't know how bad (or good)
traffic is until you get a direct measurement of LDL and HDL particle
Say you go
ahead and get those particle numbers directly measured. You're still
limited, because that is just a single datapoint from a specific
time in your life/day/week. Analogies are fun and helpful, I think,
so let's take this traffic and freeway stuff further. To get an
accurate idea of traffic, you need constant updates, right? Imagine
you counted the number of cars on the freeway at 12:05 on a Saturday
afternoon four weeks ago. That's great, but what does it tell you
about traffic at 5 PM on a Thursday? Even though it's the same stretch
of asphalt/artery, we can't divine much at all from that single
measurement. You need more data points. That traffic fluctuates
wildly is entirely uncontroversial. Any southern Californian could
tell you that. But did you know that LDL, HDL, and total cholesterol
readings in the same person can fluctuate
just as wildly, oftentimes enough to move that person from "desirable"
to "high risk" and back to "desirable" lipid status without any
nutritional or lifestyle changes in the span of a few mere weeks?
a single snapshot rarely, if ever, tells the whole story. Who woulda
But just because
the standard cholesterol test is but a snapshot of a dynamic system
in flux doesn't negate the potential usefulness of getting your
checked. As much as Conventional
Wisdom has gotten things wrong when it comes to cholesterol
and heart disease, the two do have a relationship together. There
is a connection; contrary to what the AHA might think, we just don't
have it ironed out yet. In my opinion, the most persuasive hypothesis
about the real causes of atherosclerosis and heart disease comes
from Chris Masterjohn and is highlighted in his recent AHS talk,
Disease and Molecular Degeneration," and on his
blog. It's a synthesis of the two prevailing notions regarding
cholesterol and heart disease the one which says elevated blood
plays no causal role in heart disease and the one which says elevated
blood cholesterol is the primary cause of heart disease and it
goes something like this:
normally "receive" LDL particles and remove them from circulation
so that they can deliver nutrients and cholesterol to cells, and
fulfill their normal roles in the body.
If LDL receptor
activity is downregulated, LDL particles clear more slowly from
and spend more time in the blood. Particles accumulate.
When LDL particles
hang out in the blood for longer stretches of time, their fragile
fatty membranes are exposed to more oxidative forces, like inflammation,
and their limited store of protective antioxidants can deplete.
When this happens,
the LDL particles oxidize.
LDL particles are taken up by the endothelium a layer of cells
that lines the inside of blood vessels to form atherosclerotic
plaque so they don't damage the blood vessel. This sounds bad (and
is), but it's preferable to acutely damaging the blood vessels right
So it's the
oxidized LDL that gets taken up into the endothelium and precipitates
the formation of atherosclerotic plaque, rather than regular LDL.
OxLDL, poor receptor activity, and inflammation are the problems.
But since measuring oxidized LDL in serum is difficult (oxidized
LDL gets taken up out of serum and into the endothelium rather quickly)
and expensive, we need other, more realistic, more obtainable methods.
We need to work with what we've got. It would be great if a doctor
could quickly order up an "LDL receptor activity" test, but I don't
see that happening anytime soon.
Enter the various
First up is
your basic lipid panel, the standard test the average doctor is
going to order for a patient. If you go this route, you'll typically
get four measurements: total cholesterol (TC); high density lipoprotein
cholesterol (HDL-C); low density lipoprotein cholesterol (LDL-C);
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December 22, 2011
© 2011 Mark's Daily Apple
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