Re: Beware of the rabbit with clogged arteries!

I make it a point to investigate every point made by those who think
that they have discovered some "study" that demonstrates something
substantially different from what I have been saying here for a long
time (and what many scientists have been saying for an even longer
time). One critic seems to really find these rabbit clogging studies
powerful evidence, though on close inspection, they are basically
laughable. I found a couple more (many are older and the abstracts are
not available on the internet, just the citations, but the first one
must have been an early one (1959) that hit the media during the
so-called heart disease epidemic of that period.
My comments are in brackets after the studies.

(Circulation Research. 1959;7:779.)
© 1959 American Heart Association, Inc.

Regression Studies with Safflower Oil and Sitosterol in Rabbit
Atherosclerosis
JONATHAN P. MILLER PH.D.1, G. FREDERICK LAMBERT PH.D.1, DOUGLAS V.
FROST PH.D.1

1 Nutrition Research Department, Abbott Laboratories, North Chicago,
Ill.

Hypercholesteremia with atherosclerosis was induced in male rabbits by
feeding hydrogenated coconut oil as the only lipid in a purified diet.
Replacing the hydrogenated coconut oil by safflower oil produced a
profound fall in plasma cholesterol in rabbits. Supplementing the
safflower oil with sitosterol at 3 per cent of the oil weight caused an
even greater decrease in plasma cholesterol. Although in both cases the
further development of aortic atheroma was arrested, there was no
detectable regression of existing lesions, over 24 weeks. Hydrogenated
coconut oil feeding produced high plasma and liver cholesterol levels
in rabbits. When small amounts of safflower oil were fed in addition to
the hydrogenated coconut oil, the elevation of plasma or liver
cholesterol was much less.

[so it seems that high cholesterol levels is the key - what they
should have done is to feed cholesterol in the diet, along with
safflower oil, to get the cholesterol level to be the same as it would
be if fed the HCO, then we would know if it is the cholesterol-raising
effect of the HCO that is causing the "atherosclerosis," though we
still would not know if overall mortality was effected, which would be
nice to know]




Br J Exp Pathol. 1985 Feb;66(1):35-46.

Hyperlipoproteinaemia and atherosclerosis in rabbits fed low-level
cholesterol and lecithin.

Hunt CE, Duncan LA.

Dutch-Belted rabbits were fed for 18 months an atherogenic semipurified
gel diet containing 14% hydrogenated coconut oil and 0.06% cholesterol
(approximately 0.15 mg/kcal) or a non-atherogenic basal gel diet
containing the same ingredients but with no coconut oil or cholesterol.
Rabbits fed atherogenic diet developed hypercholesterolaemia (means 733
mg/dl at 16 months) and plasma lipoprotein (LP) distribution shifted
from a pattern in which high-density lipoproteins (HDL) predominated to
one in which very-low-density lipoproteins (VLDL) were predominant.
Total cholesterol/triglyceride ratio in d less than 1.006 LP changed
from 0.3 to 1.8. Plasma cholesterol and LP distribution returned to
normal in rabbits fed atherogenic diet for 18 months followed by
atherogenic diet plus 3% soya lecithin for an additional 4 months.
Rabbits fed atherogenic diet for 18 months had extensive, usually full
circumference fibromuscular plaques in main branches of coronary
arteries and all portions of aorta which compromised lumen area by
almost 50%. These lesions were modified in rabbits fed atherogenic diet
plus lecithin. The plaques lacked foam cells and cholesterol clefts,
were less cellular with a distinct fibrous surface and occupied less
space. Animals fed basal diet did not develop hypercholesterolaemia
(means 86 mg/dl at 16 months), although distribution of plasma LP
shifted slightly in favour of increased low-density lipoproteins (LDL)
and decreased HDL compared with rabbits fed standard commercial diet.
Basal diet rabbits had no coronary atherosclerosis and only minimal
focal foam cell lesions in proximal aorta. Liver injury including fatty
change, cholangitis and portal fibrosis occurred in animals fed
atherogenic diet. Thus, rabbits fed appropriate diets low in
cholesterol accumulate cholesterol-enriched LP in their plasma and
develop lesions in abdominal aorta and main branches of coronary
arteries which are similar to those in man. Also, in this experimental
model, dietary lecithin promotes a return to normal of the LP
distribution profile and removal of lipid from established
atherosclerotic plaque.

[From these two studies, it again seems most likely that rabbits are
very sensitive to cholesterol, and if they were fed the usual dry,
processed/refined food (which is what they seem to have been fed),
instead of what they would eat in nature, they would lack antioxidant
protection against cholesterol oxidation. Moreover, we don't know if
much of the cholesterol they were fed was already oxidized. Blaming
HCO is epiphenomenal, in that the main problem is that at least this
breed of rabbits don't handle cholesterol well, and may handle
oxidized cholesterol very badly (compared to humans). Since they
don't eat cholesterol naturally, as rats often do, the interesting
question is, why would anyone choose rabbits when rats are available
and cheaper and just as easy to deal with?

However, I'd like to see a rabbit study in which the rabbits are fed
safflower oil and a lot of cholesterol of the form that these rabbits
were given, along with the dry, processed food. The underlying
mechanism, that is, free radical damage to cholesterol, would then be
obvious, if it were the mechanism in rabbits as well as humans. Since
this does not happen in humans who consume large amounts of fresh
coconut oil, one wonders why they are so concerned with rabbit
atherosclerosis. Once again, the desire to "prove" something that
does not seem to be the case from a scientific perspective appears to
be rearing its confused and possibly conflicted (as in conflicts of
interest) head. If one were to feed rats diets high in non-oxidized
cholesterol (as in boiled eggs) and either fresh coconut oil or
commonly available refined safflower oil, I would put my money on the
safflower oil group dying at younger ages. Again, if anyone wants to
take me up on one of my experimental offers, let's talk details. The
refined safflower oil, which is highly peroxidizable, will oxidize the
cholesterol and cause the animals problems beyond
"atherosclerosis." The fresh coconut oil will protect the
cholesterol in the eggs from in vivo lipid peroxidation.]

.

Relevant Pages

  • Re: high dietary cholesterol = high blood cholesterol?
    ... > But my dear, while those people's LDL goes down, their TG raises, try to do ... responsible for most cases of low HDL cholesterol levels in persons ... HDL cholesterol does not confer the same risk of atherosclerosis as do ... metabolize the fat and cholesterol that they eat. ...
    (sci.med.nutrition)
  • Re: Homo erectus, city dweller and sailor
    ... cholesterol poison by a loving hand don't increase cholosterol levels, ... The rabbits were divided into groups and fed a diet designed to raise ... Doug Weller -- ... just beginning to know what our brains are capable of doing. ...
    (sci.archaeology)
  • Re: Is the diet heart hypothesis really still alive.
    ... ::: that high levels of blood cholesterol are associated with high ... :: replace saturated fats with olive oil, canola oil and with a rape ... There are other studies of Mediterranean diets, ... Mediterranean diet have been replicated in other countries and populations ...
    (sci.med.cardiology)
  • Re: Please pray for the deeply troubled soul of dear convicted neighbor Cary Kittrell.
    ... Inhibition of intestinal absorption of cholesterol by ezetimibe or ... SR-BI/apoE double knockout mice exhibit many features of human ... occlusive coronary atherosclerosis, cardiac hypertrophy, myocardial ... intestinal cholesterol absorption inhibitor that lowers ...
    (sci.med.cardiology)
  • Re: Is the diet heart hypothesis really still alive.
    ... The quality of dietary fats is important, ... that high levels of blood cholesterol are associated with high ... subjects were adviced to replace saturated fats with olive oil, ... Thank you Juhana for drawing my attention to the Lyon study. ...
    (sci.med.cardiology)
Loading