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Tuesday, November 21, 2006

Speaking of Diet and Heart Disease....

I gave a 30-minute presentation this morning for the cardiology department at my hospital on vegetarian diets and heart disease. I've given similar talks before, but to lay people, not to cardiologists.

An important point was brought up, and it's a source of frustration for me as well: There are hundreds of randomized controlled trials of various drugs and devices for heart disease, but there isn't a single large, randomized controlled trial on vegetarian diets and heart disease.

There's evidence that a plant-based diet is good for the heart, including a small randomized controlled trial by Dean Ornish (published in Lancet in 1990) and a small observational study by Caldwell Esselstyn (Journal of Family Practice, 1995) that showed that patients on a low-fat vegetarian diet have fewer repeat cardiac events. Epidemiologic studies demonstrate that cultures with plant-based diets have very low rates of coronary disease.

But, no one is going to do a large, randomized trial of vegetarian diet and heart disease. It isn't profitable -- what pharmaceutical company would sponsor it? And even though the data that is out there strongly supports a vegetarian diet for prevention of heart disease and cancers, there will still be skepticism for lack of a large randomized-controlled trial.


jameshkoler said...

This BLOGS are very fine and all the parts are very good.
So i also give a segation-

OkraMary said...

Sounds like someone needs to get a wealthy, veg-friendly philanthropist on board to fund a study.

Lakshmi said...

So, why does it have to be a pharmaceutical company? Does't Birdseye have deep pockets? How about Big Farm? :-D

Anonymous said...

Are you familiar with Dr McDougall's work or Dr Esselstyn? Dr. Esselstyn has done research on Heart Disease and a Vegan Diet. I suggest you look at this website (if you are not already familiar with it)

VeganDoc said...

I'm very familiar with their work, especially Dr. Esselstyn's -- see the original post. Thank you for the link to Dr. Esselstyn's web site; I will link it to my blog.

Anonymous said...

Doc, Tell me what you think about the following abstract which reviews randomized controlled trials related to CHD and cholesterol. I got the reference from one of Dr. Joel Fuhrman's newsletters. Even if there aren't a lot of vegans being studied, the relationship between saturated fat, cholesterol, and CHD is, and we know that vegan diets are low in saturated fat and favorable to our cholesterol levels:

Semin Vasc Med. 2002 Aug;2(3):315-23.
Cholesterol, coronary heart disease and stroke: a review of
published evidence from observational studies and randomized
controlled trials.

Huxley R,
Lewington S,
Clarke R.
Department of Public Health Sciences, University of Oxford,
Oxford, England.

In observational epidemiologic studies, lower blood cholesterol is
associated with a reduced risk from coronary heart disease (CHD)
throughout the normal range of cholesterol values observed in
most Western populations. There is a continuous positive
relationship between CHD risk and blood cholesterol down to at
least 3 to 4 mmol/l, with no threshold below which a lower
cholesterol is not associated with a lower risk. Observational
studies suggest that a prolonged difference in total cholesterol of
about 1 mmol/l is associated with one-third less CHD deaths in
middle age. Evidence from large-scale cholesterol lowering trials in
patients at high-risk of CHD have demonstrated that much of the
epidemiologically predicted difference in CHD risk associated with
differences in cholesterol was achieved within a few years of
treatment. Moreover, these trials have demonstrated that such
therapy was not associated with increased non-CHD mortality.
Total cholesterol is transported in blood as low-density lipoprotein
cholesterol or LDL cholesterol (about 70%) and as high density
lipoprotein cholesterol or HDL cholesterol (about 30%). Since these
two cholesterol fractions have opposing effects on vascular risk, a
1 mmol/l reduction in LDL cholesterol is likely to be associated
with 40 to 50% lower CHD risk. The size of the absolute reduction
in CHD produced by lowering total and LDL cholesterol is
determined by an individual's overall risk rather than their initial
cholesterol level. Consequently, the benefits of drug treatment to
lower LDL cholesterol are greater in those at higher absolute risk of
CHD rather than at high cholesterol levels. Dietary saturated fat is
the chief determinant of total and LDL cholesterol levels. Replacing
60% of the intake of saturated fat by other fats and reducing the
intake of dietary cholesterol could reduce blood total cholesterol
levels by about 0.8 mmol/l (that is by 10 to 15%), with four fifths of
this reduction being in LDL cholesterol.
PMID: 16222621 [PubMed - indexed for MEDLINE]

heart disease said...
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