So called "good" cholesterol is
transported by high-density lipoproteins (HDL, consisting of lipids
attached to a protein carrier, hence the name) to the liver, to be
disposed of. In a recent study on 3700 British men and women (Singh-Manoux
et al.) the researches established possible link
between low level of "good" cholesterol and increased risk
of memory decline by the age of 60.
Both, researchers and the news
headline put it as "good" cholesterol being possibly protective
against age-related deterioration of memory. If true, it would
further solidify the current view of "good" cholesterol
being, generally, health protective.
But - something
doesn't add up here. If the body benefits from something being taken
out of the system more expeditiously, that "something" can only be
bad, correct? This oxymoron is more than just semantics. It reflects
misunderstanding - or ignorance - of what is actually the role of
cholesterol in our bodies and, consequently, the meaning of specific
nominal levels and relative balance between "good" and "bad"
"Good" cholesterol cannot protect your memory, or
anything else, simply because it is something being taken out of
your system. The significance of the nominal levels and the ratio of
"good" to "bad" cholesterol is that they give
indication of what is
taking place inside your body.
And we can get a good idea of what it
could be by looking back on what is it that the body uses
cholesterol for. Sounds logical, doesn't it?
After genetics, thyroid or
fat metabolism malfunctions
are ruled out, the relative increase in cholesterol supply ("bad"
vs. "good" cholesterol), indicates that the body needs and
uses more of it than usual. Also, it indicates an ongoing cholesterol
buildup within the body.
And vice versa, the relative increase in blood
cholesterol due to higher rate of cholesterol disposal ("good"
cholesterol) indicates that the body gets by without the need for
chronically higher use of cholesterol.
The question is,
it that the body uses cholesterol for?
In other words, what are the possible causes,
tissues/organs and consequences of cholesterol accumulating within
the body. We won't go
into incredibly complex details of body metabolism in general, and
cholesterol metabolism in particular, but we can establish some
useful general leads.
Let's begin with where most of body's cholesterol
is: cellular membrane.
Cells use cholesterol to fine-tune their membrane fluidity;
incorporating more cholesterol into the membrane makes it more
stiff, generally more resistant to everything entering the cell - or
attempting to - from the outside, and vice versa. It is quite
probable that damaged, or threatened cell would respond by
stiffening its membrane, trying to protect its integrity. In other
words, by using up more cholesterol.
The three primary agents inflicting
damage to the cellular membrane are free radicals,
trans fatty acids. Each of them can -
and usually does - trigger inflammatory response. Thus, the buildup
of cholesterol indicates that there is
portion of body
cells suffering oxidative damage, bio-attack, toxic exposure and/or
From this point on, it is only a matter of appropriate
tests to find out where are the focal points of this process, and
design the appropriate therapy.
Cells forming the inner
blood vessel lining
are probably among the most exposed to these damaging agents - to
which here we can also add
homocysteine - since it is the blood
where these agents first arrive from the intestine and lungs. Obviously, inner
intestinal and bronchial tube linings are also highly exposed, and so
are the organs filtering the blood - liver and kidneys.
explain why, for instance,
probiotic intestinal bacteria, by
reducing degree of intestinal toxicity/inflammation, as well as
reducing toxicity of the blood due to (probable)
leaky gut, can be helpful
in normalizing cholesterol levels.
And how does memory protection play into this?
Well, the brain is
organ with the highest lipid concentration in general, and highest
cholesterol concentration in particular. As such, it is
particularly vulnerable to fat-soluble toxins, which the body
cannot entirely eliminate. Consequently, they accumulate - you guess
right - in body's fatty tissues.
Now, "good" cholesterol, being
withdrawn out of the body, has no role in any of it; it is only
"bad" cholesterol, the one supplied to the body, that the brain
attempt to use in order to protect themselves by stiffening the
At the same time, the rate of release of cholesterol from
cell membranes is, for the same reason, likely to decrease, lowering
body's cholesterol output ("good" cholesterol).
So, the first thing you should be concerned about
if your cholesterol levels are elevated, and your good-to-bad
worsened, is possible - and probable -
excessive oxidative, inflammatory and/or
toxic damage to your cells,
especially those in the above mentioned most
exposed/vulnerable tissues and/or organs, and within the organ with
the highest cholesterol concentration - your brain.
If it is
going on inside your blood vessels, it will result in buildup of
repair proteins (fibrinogen), cholesterol and calcium, causing
atherosclerosis and cardiovascular disease. If it is affecting the
brain, it will likely cause some degree of damage to its function,
including possible accelerated memory decline.
rather common source of elevated cholesterol is getting too much of
it from the diet,
either directly (preformed), or as a result of excessive caloric
intake. Consuming excessive amounts of
animal fats will raise body cholesterol levels, unless the body
adjusts its own production accordingly.
Such adjustment takes place in about 2 in every
three individuals, on the average; so the chances that you are
not significantly affected by your dietary cholesterol intake are good, but you can't
count on it. Replacing cholesterol-containing animal fats in your
diet with unsaturated plant fats could lower your "bad" (supply)
caloric intake and following metabolic breakdown of
even proteins results in the build-up of 2-carbon acetates in the liver,
used by it for cholesterol production; thus eating too much by
could stimulate the liver to produce more cholesterol.
Yet another source of excess cholesterol is
chronic stress. Since
the body needs cholesterol to synthesize stress hormones, it does
stimulate cholesterol production ("bad" cholesterol). As these
elevated stress hormones are metabolized (broken down) in the liver,
they are transformed/transferred into the bile, and excreted into
intestines. If, however, the intestinal fiber content is very low, nearly
all of the bile - including cholesterol - will be reabsorbed
and returned to the bloodstream.
Thus degree to which chronic stress
elevate body's cholesterol levels depends - just like about every
possible negative impact on health - on the quality of your
Stress also depletes the body of
including detox and
immune nutrients, as well
as antioxidants, fueling by that
oxidative, inflammatory and toxic damage to the cells. In addition,
it negatively affects the efficiency of immune system in suppressing
cellular damage inflicted by pathogens. This, in
turn, tends to draw in more ("bad") cholesterol from the liver, and slow down
the pace at
which the body disposes of it.
Of course, all cholesterol that body channels into
the bile, not only the small portion coming from metabolized stress hormones,
would be reabsorbed in the absence of dietary fiber.
adrenal hormones, like cortisone, are also also needed to regulate
inflammatory process. These hormones are also made of cholesterol. This is one more mechanism through which
inflammation - and therefore excessive cellular exposure to
oxidative, toxic or pathogen exposure as well - tends to stimulate liver cholesterol production,
contributing to elevated cholesterol levels (as many of us know, suppressing
inflammation is one of the common purposes of cortisone injections).
These are only brief outlines of some of the main
possibilities of a meaningful
interpretation of the causes and health effects of
body's cholesterol levels. Hopefully, both media and (some)
researchers will move beyond the point of skin-deep interpretations,
such as, for instance, stating that "good" cholesterol "protects
this", or "has a role in that". It is good to know what is actually
taking place in your body.