Re: Low Hdl

[Guest guest]

on HDL

Jouirnal Of The American Dietietic Association

April 2004 * Volume 104 * Number 4

Research: commentary

Was Dr Atkins right?

Dean Ornish, MD* [MEDLINE LOOKUP]

What about HDL? TOP

The reduction in HDL-C that may occur on a low-fat diet is another example of a

half-truth that is confusing to many people. HDL returns cholesterol to the

liver for metabolism, a pathway known as reverse cholesterol transport. Most

Americans consume a diet high in saturated fat and cholesterol, so those who are

able to increase HDL-C in response to this diet are at lower risk than those who

cannot, since they will be more efficient at metabolizing excessive dietary fat

and cholesterol. In simple terms, those with higher HDL-C levels have more

" garbage trucks " (HDL) to get rid of the " garbage " (excessive fat and

cholesterol).

However, reducing dietary fat and cholesterol may cause a decrease in HDL-C

because there is less need for it. This does not confer the same risk of

atherosclerosis as in Americans with low HDL levels who are consuming a high-fat

diet (41). In other words, when you have less garbage, you need fewer garbage

trucks to remove it, so a reduction in HDL on a low-fat diet is not harmful.

There are no data showing that the physiologic reduction of HDL-C levels with a

low-fat diet is detrimental, especially in that LDL-C usually decreases more

than HDL-C (42). In locations such as Asia, where a low-fat diet has been the

norm, HDL-C levels are low, yet the incidence of CVD is among the lowest in the

world (43). In rural China, for example, the average LDL is less than 95 mg/dL.

In contrast, someone who increases the amount of fat and cholesterol in their

diet (eg, an Atkins diet) may increase their HDL-C because their body is trying

to get rid of the extra garbage (fat and cholesterol) by increasing the number

of available garbage trucks (HDL). Eating a stick of butter will raise HDL-C in

those who are able to do so, but that does not mean that butter is good for the

heart. HDL-C is predictive of relative heart disease risk only in populations in

which everyone is eating a similar high-fat diet, such as the Framingham

population.

To understand better the mechanism of this phenomenon, Breslow and colleagues

studied the turnover of HDL apolipoproteins (apo) A-I and A-II in 13 subjects on

two contrasting metabolic diets. Upon changing from high to low intake of

saturated fat and cholesterol, the mean HDL-C decreased 29%, whereas apo A-I

levels fell 23%. Mean apo A-II levels did not change. The fractional catabolic

rate (FCR) of apo A-I increased 11%, whereas its absolute transport rate

decreased 14%. The decrease in HDL-C and apo A-I levels correlated with the

decrease in apo A-I transport rate but not with the increase in apo A-I FCR. In

contrast, within each diet, the HDL-C and apo A-I levels were inversely

correlated with apo A-I FCR both on the high- and low-fat diets but not with apo

A-I transport rate (44).

Therefore, diet-induced changes in HDL-C levels correlate with and may result

from changes in apo A-I transport rate. In contrast, differences in HDL-C levels

between people on a given diet correlate with and may result from differences in

apo A-I FCR. The mechanism of the effects on HDL-C levels of changing from a

high- to low-fat diet differs substantially from the mechanism explaining the

differences in HDL-C levels between individuals who are eating a high-fat diet.

In summary, decreases in HDL-C due to a low-fat diet have a very different

prognostic significance than someone who cannot raise HDL-C as much on a

high-fat diet.

Raising and lowering HDL-beneficial or harmful? TOP

An example of the half-truth of saying that anything that raises HDL-C is

beneficial whereas anything that lowers it is harmful came at the November 11,

2003 annual scientific session of the American Heart Association. A paper was

presented from Tufts University titled " One Year Effectiveness of the Atkins,

Ornish, Weight Watchers, and Zone Diets in Decreasing Body Weight and Heart

Disease Risk. " The researchers concluded " All diets resulted in significant

weight loss from baseline and all but the Ornish diet resulted in significant

reductions in the Framingham risk score " (45). This study was widely reported

and caused many to say, " See, another study showing that the Atkins diet is good

for your heart. " It sounds good, but it is not true.

The Framingham risk score is calculated from age, sex, total cholesterol, HDL,

smoking, and systolic blood pressure (46). Only total cholesterol and HDL

changed in this study, so these were the only factors in determining the risk

score. Total cholesterol decreased much more on the Ornish diet than on any of

the other diets. However, HDL increased more on the other diets, so the

differences in the Framingham risk score were due primarily to changes in HDL.

The abstract did not mention that people lost the most weight on the Ornish

diet, it was the only one to significantly lower LDL-C, and it was the only one

to significantly lower insulin (even though one of the main premises of the

Atkins and Zone diets is their purported effect on insulin). Also, C-reactive

protein and creatinine clearance were significantly lowered only on the Ornish

and Weight Watchers diets.

As stated earlier, a low-fat, whole foods diet has been proven to reverse heart

disease using actual measures of coronary atherosclerosis and myocardial

perfusion, whereas none of the other three diets has been shown to do so. It was

terribly misleading when this abstract made it appear as though the Atkins diet

is better for your heart. This is especially incongruous when, as mentioned

earlier, the only study to examine blood flow on the Atkins diet found that it

actually worsened (35).

[Guest guest]

Thanks, Jeff,

Very nice. I like it because I am a low HDL person ever since they started measuring my cholesterol.

My 81yo bro has very nearly the same.

One comment I can attest to, is that a low sodium intake <1500 mgs can change the measuring stick.

I usually go in fasted for the bloodwork, and that combined with a low fluid volume, will change things like Ca, cholesterol measurements, and PSA.

The test standards have to change for Ornish users and for low sodium types. If I don't remind my doctor, I'll be getting a new drug, like zetia when I eat very little cholesterol.

Regards.

----- Original Message -----

From: Jeff Novick

Sent: Monday, May 09, 2005 4:39 PM

Subject: RE: [ ] Low Hdl

on HDLJouirnal Of The American Dietietic AssociationApril 2004 * Volume 104 * Number 4 Research: commentaryWas Dr Atkins right?Dean Ornish, MD* [MEDLINE LOOKUP] What about HDL? TOP The reduction in HDL-C that may occur on a low-fat diet is another example of a half-truth that is confusing to many people. HDL returns cholesterol to the liver for metabolism, a pathway known as reverse cholesterol transport. Most Americans consume a diet high in saturated fat and cholesterol, so those who are able to increase HDL-C in response to this diet are at lower risk than those who cannot, since they will be more efficient at metabolizing excessive dietary fat and cholesterol. In simple terms, those with higher HDL-C levels have more "garbage trucks" (HDL) to get rid of the "garbage" (excessive fat and cholesterol).However, reducing dietary fat and cholesterol may cause a decrease in HDL-C because there is less need for it. This does not confer the same risk of atherosclerosis as in Americans with low HDL levels who are consuming a high-fat diet (41). In other words, when you have less garbage, you need fewer garbage trucks to remove it, so a reduction in HDL on a low-fat diet is not harmful.There are no data showing that the physiologic reduction of HDL-C levels with a low-fat diet is detrimental, especially in that LDL-C usually decreases more than HDL-C (42). In locations such as Asia, where a low-fat diet has been the norm, HDL-C levels are low, yet the incidence of CVD is among the lowest in the world (43). In rural China, for example, the average LDL is less than 95 mg/dL.The abstract did not mention that people lost the most weight on the Ornish diet, it was the only one to significantly lower LDL-C, and it was the only one to significantly lower insulin (even though one of the main premises of the Atkins and Zone diets is their purported effect on insulin). Also, C-reactive protein and creatinine clearance were significantly lowered only on the Ornish and Weight Watchers diets.As stated earlier, a low-fat, whole foods diet has been proven to reverse heart disease using actual measures of coronary atherosclerosis and myocardial perfusion, whereas none of the other three diets has been shown to do so. It was terribly misleading when this abstract made it appear as though the Atkins diet is better for your heart. This is especially incongruous when, as mentioned earlier, the only study to examine blood flow on the Atkins diet found that it actually worsened (35).