The Confusion About Cholesterol


By Syd Baumel (Dealing with Depression Naturally, McGraw-Hill, 2000)
For years, scientists have been squirming over a body of data that just
can't be. Low blood cholesterol is supposed to be good for you. It keeps
your arteries clear. Yet in most clinical trials it has also meant
slightly, but significantly, more depression, more suicide, more fatal
accidents, and more death by homicide. The patient killed himself, but
boy were his arteries clean!
There is no relief in the epidemiological literature. In study after
study, low cholesterol has kept popping up in people with a history of
violence, early-onset alcoholism, depression, and other psychobehavioral
dysfunctions.
These are precisely the kinds of aberrations one would expect to see in
people with serotonin deficiency. And this is exactly what scientists
believe is happening.
In the brain, cholesterol is an abundant and integral component of neuron
membranes, helping serotonin bind to the synaptic receptors that heed its
laid back call. Raising or lowering the cholesterol content of monkeys'
diets correspondingly boosted or lowered the serotonin activity in their
brains, in a 1994 study by Jay Kaplan et al. It had the same effect -- in
reverse -- on the monkeys' disposition to impulsive behavior and
violence.
Psychologists would call this a classic example of "cognitive
dissonance." How can we reconcile the cholesterol we love to hate with
these dissonant findings?
We can start by remembering that cholesterol is a chemical that our
livers go out of their way to make. It is from cholesterol that all the
steroid hormones in our bodies are synthesized, including such mood
regulators as estrogen, progesterone, testosterone, pregnenolone, and
DHEA. The brain sucks up cholesterol like a sponge, for good reason.
It's possible that for some people whose livers aren't up to producing
enough cholesterol (alcoholics, perhaps?), something like a "recommended
daily allowance" of dietary cholesterol might actually be a good thing.
Conceivably, for some depressives who suffer from signs of low serotonin
syndrome -- impulsiveness or poor self-control, violent outbursts, early
onset alcoholism -- adequate cholesterol could mean the difference
between merely having impulses that lead to depressing consequences and
acting upon them.
But there could be a somewhat different explanation. Only a tiny fraction
of our body's cholesterol -- the portion that flows in the bloodstream --
gives the rest a bad name. And of that portion, it's only the "bad,"
low-density lipoprotein cholesterol, or LDL-C, that plugs our arteries.
And then only if it's been oxidized, because we haven't bathed our blood
with enough antioxidants, like vitamins C and E. The "good," high-density
lipoprotein cholesterol, or HDL-C, in the bloodstream actually lowers the
risk of cardiovascular disease. Yet many cholesterol-lowering drugs and
diets indiscriminately lower both the good and the bad.
I've noticed a trend for clinical trials in which HDL-C is raised (as
with niacin and the statins) not to be plagued by the low serotonin
curse. In keeping with my suspicions, in a study of suicide attempters by
G. Engstrom et al., high blood levels of HDL-C meant high brain
serotonin; high LDL-C didn't. In a study by A. S. Wells et al., a low fat
diet put healthy volunteers in a rather angry, hostile, "low serotonin"
mood. But the only cholesterol it lowered was the good kind. In a study
of 300 healthy Swedish women by M. Horsten et al., while very, very low
total cholesterol levels were indeed associated with more symptoms of
depression, high HDL-C was significantly associated with fewer symptoms.
In yet another study by Maes et al., while patients with major depression
had lower cholesterol than normal controls, their HDL-C levels were lower
still. In fact, the very lowest HDL-C levels were found in men who had
attempted suicide -- violent suicide is practically synonymous with low
serotonin. In apparent contrast, however, in a study by Papassotiropoulos
et al., higher cholesterol meant less acute suicidality in psychiatric
inpatients. But only total cholesterol was measured.
And then we come to niacin and aerobic exercise.
Megadoses of niacin are a well-established treatment for high
cholesterol. But while niacin lowers LDL-C, it substantially raises
HDL-C. And as we've seen in the chapter on vitamins, it seems to make
people less depressed and suicidal, not more.
For its part, moderate aerobic exercise is not only the optimal physical
activity for lowering bad cholesterol and raising good, it's an
exceptionally well-documented ward against depression and other kinds of
malaise.
So the research tends to suggest it's not low cholesterol per se that's
the problem, but low HDL-cholesterol -- low good cholesterol.
There is at least one stark exception: Jay Kaplan et al.'s monkey study,
mentioned earlier. In it, a heavily cholesterol-supplemented high-fat
diet, when compared to an identical diet with no added cholesterol,
nearly tripled total blood cholesterol and cut HDL-C in half. Yet it
nearly doubled the monkeys' brain serotonin, making for a mellower group
of monkeys.
Joseph Hibbeln and Norman Salem Jr. believe they have a
counter-explanation -- if not for Kaplan's carefully controlled study,
then at least for many others. They note that, historically, low
cholesterol diets have been of the high vegetable oil and margarine kind,
the kind that results in a major increase in the dietary ratio of omega-6
to omega-3 fatty acids. But omega-3's are the only EFAs that raise HDL-C.
And, as we've seen, they're the best EFAs for building supple synapses
for neurotransmitters like serotonin.
For the monkeys on Kaplan et al.'s high fat, low omega-3 diet, the extra
cholesterol may have been a kind of necessary evil. But on a diet with an
optimal omega-3/omega-6 balance, perhaps it is safe, after all, to keep
"watching our cholesterol" without worrying that we'll wind up in a post
office some day, all sweaty and disgruntled, with a knapsack full of
ammo.
References: http://www.mts.net/~baumel/References.html





Jay Banks

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Success is the journey...
not the destination