On Thu, 14 Jun 2001, Dori Zook wrote:

> >how does it work ? (carb reduction = hypertension control)
>
> Here's the role of carb reduction in the lowering of cholesterol levels,
> something in the same ballbark (for any newbies):

I think the main reason why carb reduction helps many (not all)
to achieve normal blood pressure is that it has a diuretic
effect.  For some people, the extra sodium and water retention
caused by a higher-carb diet is enough to elevate blood pressure.

> Q: Won't all that meat and eggs raise my cholesterol?
> A: No, unless you eat a diet that's also high in sugar and starch.  Of the
> cholesterol in your blood, only about 15 to 20% comes from your diet-your
> body, primarily the liver, makes the rest.  The signal to make cholesterol
> comes from the hormone insulin.  When it's high in the blood, the body makes
> cholesterol.  Insulin rises in response to dietary carbohydrate-starch and
> sugar-not dietary fat or cholesterol.
> (source: press kit, Drs. Michael & Mary Dan Eades - info from them, worded
> by my firm, i.e. me)

While this is all true, I am mildly annoyed by the fact that they
fail to mention the effect of certain saturated fats, such as
palmitic acid, on hepatic LDL receptors.  You see, the
*production* of cholesterol is not the only thing that affects
serum levels; the rate at which it is removed from the blood also
matters, and the LDL receptors control this.  It is well
documented that palmitic acid and some other saturates
downregulate these receptors, and this can and does affect serum
LDL levels.

It's not just insulin.

To make matters more complicated, I recently read Batmanghelidj's
analysis of elevated cholesterol as a symptom of dehydration.
The science makes sense, to a layman at least, and he has
published some of his theories in peer-reviewed journals.
Anyway, what interests me about this is the fact that people on
lowcarb diets are actually *more* at risk for dehydration,
precisely because of the diuretic effect of carb reduction.  If
Batmanghelidj is right, this could be yet another reason why a
signficant number of people find that their LDL goes up when they
sharply reduce carbs (Just reading the messages at
http://eatprotein.com is enough to establish that).  He says, for
example, that urine should be pale in color, or clear.  I
generally drink the recommended four pints a day, but to have
paleo or clear urine I need to drink a minimum of six, I've
discovered.  Batmanghelidj claims that dark urine is the simplest
test to determine that one needs more water.

And as the Eades and others (Phinney, for example) point out,
people on ketogenic or near-ketogenic diets are at risk for
electrolyte depletion, again because of the diuretic effect.
They need more salt, potassium, etc.  Electrolyte depletion can
be dangerous.

Todd Moody
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